Insulate Britain! Yes, but by how much?

If you are confused about what to do about retrofit, you are probably not alone. There is so much mixed and conflicting messaging. Often statements are made in the media that are untrue and go unchallenged.

Some experts say we need to insulate our homes so well they will hardly need any heating! Others say we need to get off gas as fast as possible by installing heat pumps.

Who is right?

Part of the confusion is that commentators can have different objectives in mind when expressing their opinions:

  • To reduce household bills;
  • To improve comfort;
  • To reduce reliance on gas;
  • To lower risks to future bills, from volatile gas markets;
  • To reduce the carbon footprint of heating.

Or some combination of these. But these assumptions are often not made clear, and homeowners can be led down different paths depending on who they talk to.

Now, in the face of the climate emergency, everyone is saying that the last of these is something they care deeply about, but the pathway to getting to net zero in heating is something that is hotly debated.

We don’t have much time to get this right, and as Voltaire once noted, the best should not be the enemy of the good. We need a pragmatic way forward.

Energy Performance Certificates

Householders will often be further confused when they look at the Energy Performance Certificate (EPC) of their home or one they want to buy. EPCs are increasingly seen as unfit for purpose in the effort to decarbonise heating. The Country Land and Business Association (CLA) stated (as quoted in an Historic England report from 2018).:

“The EPC confounds cost-effectiveness, energy efficiency and environmental performance, giving an inadequate estimate of all three. … it must focus solely on one of .. [to] be an effective baseline for policy interventions”

An EPC in its current form has never recommended a heat pump as a primary measure, because of in-built biases against heat pumps. If we really want to encourage ‘whole house’ retrofit that includes a sufficiency of insulation work and displacing gas (or oil or LPG) boilers with heat pumps, we will need instruments that are fit for purpose (see Updates A.)

So what to do?

Householders will naturally ask: How much will it cost? How fast can it be done? Who can I get to advise me? What is the carbon reduction? Who can do the work to a good standard?

Is ‘deep retrofit’ required?

The Committee on Climate Change (CCC) in their 6th Carbon Budget stated (based on very detailed modelling of scenarios, costs and risks):

‘By 2030 37% of public and commercial heat demand is met by low-carbon sources. Of this low-carbon heat demand 65% is met by heat pumps, 32% district heating and 3% biomass. By 2050 all heat demand is met by low-carbon sources of which 52% is heat pumps, 42% is district heat, 5% is hydrogen boilers and around 1% is new direct electric heating.’

for their ‘balanced pathway’, and they did not assume deep levels of retrofit (p.113):

‘Energy efficiency and behavioural measures in our Balanced Pathway deliver a 12% reduction in heat demand to 2050’,

which implies quite modest fabric retrofit. This, on average, requires an estimated budget (see p. 297) of just £10,000 per household. This is far below what is the estimated ‘deep retrofit’ budget of nearly £40,000 [1].

The CCC are clearly working on the basis of pragmatic or sufficient levels of insulation and other fabric measures, not ‘deep’ retrofit.

The Retrofit Academy is devoted to training to improve the quality of assessments and implementation of ‘fabric’ measures (insulation, air quality, etc.), which is to be applauded. It is however concerning that they essentially marginalise heat pumps [2]:

“Deep extensive retrofit and fabric first approach needs to be the main focus of reducing carbon emissions before we will be able to move to low carbon heating technologies 100%”.

There is clearly a problem here, as this is not an isolated opinion.

The ‘retrofit community’ generally have established an article of faith that ‘deep retrofit’ is essential. This is a belief that has very deep roots and predates concerns about the climate emergency. Key organisations in the public and private sector promote this belief.

Their motivation is to create greater comfort in homes and to lower heating bills, and who can argue with this?

The problem is that it isn’t a realistic strategy for reaching net zero in the fastest time possible [3].

The benefits in financial terms for householders do not favour a deep retrofit approach [4], but suggests that buyers do value heat pumps [5].

The Retrofit Academy justify their position on heat pumps based on the belief that that the grid cannot cope.

This is the same kind of argument that is often used for why we can’t adopt Electric Vehicles (EVs): because there aren’t enough charging points. On that basis we’d never have replaced horse-drawn carriages with petrol cars, or indeed any technology that displaces an old technology. In all such cases, the infrastructure is developed in parallel with the adoption of the technology in use. You don’t wait till you have a fully developed charging network and beefed-up electricity grid (particularly at its periphery) before you start selling EVs.

The electrification of much of our energy use is an inevitable strategic transformation of the energy system for many reasons, not least of which is the end-use efficiency improvements that technologies like EVs and heat pumps deliver. The other strategic game changer is that the end-use of energy does not care where the electricity comes from: a wind farm in the North Sea; the solar PV on a householder’s roof; a community solar scheme; a nuclear power station; or even, fusion energy (if it ever becomes a commercial reality). Electrification completely future proofs our energy system (even those parts of the economy like Aviation that need ‘chemistry’ to decarbonise, can get synthetic fuels from renewable electricity).

As for the grid, the issue has been overstated. There will be some strengthening of the grid required but a whole host of measures mitigate peaks in demand, including energy storage (at multiple scales), demand shifting, smart metering, etc. These will ensure that the grid can readily cope with future demand. No one is expecting that we have a 100% switch to heat pumps overnight, any more than petrol cars replaced horse-drawn carriages overnight. It is a multi-track transformation of energy generation, distribution and use. Local generation can have a remearkable impact on the scaling up of renewables as discussed here.

A Net Zero Toolkit for Retrofit

Retrofit assessors need to take an holistic and pragmatic view of the problem of decarbonising heating.

The ‘Net Zero Toolkit’ [1] is an encouraging document because it takes an approach which is very much along these lines. This document reiterates what PAS2035 is trying to achieve:

PAS 2035 follows two core principles:

  • A ‘fabric first’ approach to reduce the heat demand of a building as much as possible and to ensure newly airtight homes are well ventilated and avoid issues with damp and humidity.
  • A ‘whole house approach to retrofit’ to ensure retrofit plans for homes consider improvements to the fabric, services and renewable energy generation in a coherent way to minimise both risks and carbon emissions.

In other words, we need to consider fabric measures and getting off gas (or other fossil fuels) in parallel.

It also takes a ‘risk’ based approach, recommending that assessors consider the possible hurdles not only the benefits of different courses of action.

For a 90m² home (the average floor area for UK houses) the ‘Net Zero Toolkit’ provides costing for a both ‘shallow’ and ‘deep’ retrofit. Including all the potential measures it comes to a total cost of £14,770 for ‘shallow’ and £54,220 for ‘deep’ retrofit. But a heat pump is only included in the ‘deep’ retrofit case, so this is still pursuing the view that deep fabric measures are required before including a heat pump.

Leaving heat pumps till later, after the retrofit budget has potentially been blown on fabric measures, is not the answer. So while the ‘Net Zero Toolkit’ is a great improvement on the apparent Retrofit Academy position, it could go further.

In terms of actual measures recommended, I feel it still falls short of recognising that heat pumps need to be included much earlier in the conversation.

If we include only those measures related to ‘fabric’ (i.e. exclude heating systems and solar energy) the costs are reduced to £10,970 and £38,720, respectively.

How many 90m² floor area home owners have £38,000 to spend, and still have money and appetite left over to do the heat pump project?

‘Fabric first’ can easily become ‘Fabric only’ on this path.

We still have a lack of recognition of the urgency of getting off gas.

What does the Government say?

The Department of Business, Energy and Industrial Strategy (BEIS) in a recent study have findings that completely contradict the position of the Retrofit Academy. BEIS conclude:

‘This project shows that Great Britain’s homes can convert to electric heating at a cost far lower than the accepted wisdom. This can be achieved with no threat to comfort, and greenhouse gas emissions will fall very dramatically as a result.’

In answer to the question on what should be ‘the balance of heating technologies to insulation measures’ they conclude:

‘The work focused on total costs of ownership over 15 years. For most house types and most electric heating systems, the cost-optimal packages of measures have very limited fabric improvements – most commonly just draught-sealing and top-up loft insulation. High-cost improvements, like internal or external wall insulation, hardly ever repay the capital costs over 15 years.’

This is in part why the Government and Climate Change Committee are following a pragmatic approach and see a combination of heat pumps and district heating as cornerstones of heating decarbonisation.

Why heat pumps must be considered at the start of a retrofit conversation

If we focus on avoiding dangerous global warming, the single biggest thing a householder can do to reduce their carbon foot print is to install a heat pump.

Yes, it must be a fair transition and poorer families need help with grants or other measures to switch away from fossil fuels, but the direction of travel is clear.

I previously illustrated this (see here ), using data from the Energy Saving Trust, plotting the capital cost of different measures versus the carbon saving of those measures per year. I am including this graphic below.

Air-Source Heat Pumps (ASHPs) are now so efficient they compete very favourable with Ground-Source Heat Pumps (GSHPs), and at half the project cost, so we focus on ASHPs, which are likely to dominate the market [6].

An ASHP is the single best way for a householder to reduce their carbon footprint, by a long way.

A retrofit assessor may say,

‘Yes, but we have to consider comfort too. That bay window is poorly insulated so, whether it is a gas boiler or heat pump heating the home, sitting by the window will feel cool and only fabric measures can fix that’.

This is true and a householder needs to express their requirements clearly, and be presented with the options and costs. They can then judge which measures they ‘value’, in terms of the different criteria – comfort, capital costs, running costs and carbon reduction.

Different people with exactly the same situation may arrive at different conclusions.

But if they say that carbon saving is their number one priority, and secondly, they’d like to keep running costs similar, then a heat pump and modest fabric measures is an option that will score extremely well (or should do, if the assessment tools are fit for purpose).

Maybe, instead of the mantra ‘Fabric first’, we need ‘Efficiency first’, because it is that which delivers lower carbon emissions.

How do we deal with hard to treat homes?

The conversation often centres on old leaky homes, of which the UK famously has many. The Buildings Research Eastablishment (BRE) estimated a while ago that the UK had over 10 million ‘hard to treat’ homes (and there are nearly 30 million homes with gas boilers in the UK). About half of these buildings (about 5 million) were built before 1900.

These 10 million are often but not exclusively larger homes with high gas heating bills. So addressing the needs of this 1/3rd of the retrofit challenge would make a disproportionately large contribution to decarbonising heating in the UK.

But whether it is Roger Harrabin reporting on the BBC, or many others who count themselves as ‘green’, we hear it stated repeatedly (without reference to evidence) that householders must have high levels of retrofit before even considering a heat pump.

Some will even repeat the myth that you cannot heat old ‘leaky’ buildings with a heat pump. This is one of the myths that is addressed here.

Heat pump scepticism is wrong for several reasons:

  • you can heat any building with a heat pump that can be heated with a gas boiler (you just need to size the heat pump and the emitters/ radiators correctly);
  • with the efficiency of modern heat pumps and quite modest insulation, a heat pump can match or even reduce the running costs of the boiler it is replacing, as shown here;
  • because the electricity grid is getting greener and greener every year, once a heat pump is installed the heating gets greener and greener with every year that follows (as illustrated in the graphic earlier).

But the questions remain: how do we deal with hard to treat homes? How much insulation do we do before we get rid of the old gas boiler?

The heat demand of a building is an important measure of its efficiency, but how do you compare the thermal efficiency of a large 6-bedroom detached house with a 3-bedroom semi? The fair way to do it is to divide the heat demand by the floor area of the house, which gives a measure – the heat demand per unit area – that is a universal measure of the ‘efficiency’ of the building’s fabric.

In the UK, the average home has an annual heat demand, using this measure, of about 130 kilowatthours (thermal energy) per square metre per annum (or 130 kWh/m².a for short). A new build, highly efficient ‘PassivHaus’ requires only 15 kWh/m².a. The Association of Environmentally Conscious Builders (AECB) have a target of 50 kWh/m².a when carrying out a (fabric) retrofit project, but they will relax this (e.g. for a Listed Building) to 100 kWh/m².a in some case, because some measures (like wall insulation) may prove impractical or impossible to include.

The implementation of retrofit on old buildings needs to be done with considerable experience and care, as a report by the Sustainable Traditional Buildings Alliance (STBA), in part sponsored by Historic England, explored.

Let’s start with a 90-100m² home with solid walls that is poorly insulated and ‘hard to treat’, and requires nearly 200 kWh/m².a to heat it currently with its gas boiler.

The following sequence considers a sequence of options (A-E) for when to install an Air-Source Heat Pump (ASHP), alongside increasing levels of ‘fabric’ retrofit measures. As we move from left to right on the bottom axis, fabric measures are added that reduce the heat demand of the building. That in turn will reduce the cost of the heat pump project.

Because we still need hot water and some heating, the drop in the cost of the heat pump project is less dramatic than the rise in the cost of the fabric measures, and there will be a cross-over point where the cumulative cost of the fabric measures is equal to the cost of installing a heat pump (at that level of building efficiency). Let’s run through the options.

A. Doing nothing on fabric or gas means bills will escalate

This is the start – the ‘do nothing’ option.

There is a serious risk that such a home will have lower resale value in the future, and will of course not contribute to lowering the carbon footprint of the home.

By starting to think about retrofit (including getting off gas), home owners might find themselves doing things they have put off for years, like clearing the loft (ready for insulation), and fixing that leaky front door.

B. Getting off gas early prioritises planet, without bills needing to rise

In this case, the householder installs an ASHP early in their retrofit journey, alongside limited fabric measures, such as loft insulation to modern standard, and seals / brushes for doors and sash windows to deal with drafts.

It may be a surprise to people that getting off gas early prioritises planet, without bills needing to rise. The reasons for this are:

  • A 25 year old, 70% efficient gas boiler wastes energy, so the net cost of a unit of ‘heat energy’ delivered is greater than 3p (the nominal unit price for a kWh of gas in July 2021), so 3p/0.7 = 4.3p per kWh of heat delivered/ required.
  • The nominal cost of electricity to run the heat pump (at July 2021 rates) is 15p per kWh. Taking a performance of 300% for a modern properly installed heat pump over the seasons, the householder would be paying 15p/3.0 = 5p per kWh of heat delivered.
  • Assuming that the limited measures taken mean that heat demand reduces by 20% less then we would paying effectively 4p instead, which is lower more than old unit cost (4.3p)
  • As levies on electricity move over to gas in coming years (as the Government has indicated), the running costs of the ASHP will lower further (and will rise for the gas).
  • As the electricity grid gets greener and greener, so does the heat pump, without the householder having to do anything, so the carbon reductions delivered improve year on year.
  • It is crucial that the house has a proper heat loss assessment done, and the heat pump is sized correctly, and that radiators are also assessed and upgraded where necessary on a room by room basis.

This refutes the belief that early adoption of a heat pump is a no-go area for hard to treat homes.

C. Further pragmatic fabric measures lower heat demand and bills

In this case a householder installs an ASHP, and in addition to limited fabric measures – loft insulation to modern standard, and seals / brushes for doors and sash windows to deal with drafts – installs:

  • pragmatic window measures (replacing some windows with double or triple glazing but prioritising lower cost secondary glazing, particularly in conservation area), and;
  • for one or two rooms, additional measures for cold walls or floors where possible, for comfort reasons if nothing else, and;
  • might add localised mechanical ventilation and heat recovery (MVHR) for a specific room or two (kitchen and shower) to deal with condensation issues.

Alongside reducing bills, these fabric measures can deliver improved comfort (such as in key problem areas like bay windows).

D. More fabric measures reduce bills, but can delay getting off gas

The householder installs an ASHP late after extensive and often disruptive retrofit measures to many rooms, including double or triple glazed new windows throughout and insulation for some floors and walls, and extensive MVHR (Mechanical Ventilation and Heat Recovery) recommended to deal with moisture that would otherwise be trapped.

Older buildings are used to ‘breathing’ and that prevents the build up of moisture. As we greatly reduce leaks in these buildings, and add insulation, there are significant risks of harm to the traditional underlying fabric of the building due to moisture. Historic England has documented many cases where harm has been done in old buildings, and they recommend the use of breathable insulation materials to minimise such risks. Moisture can give rise to health issues if mould results.

That is why PAS2035/ PAS2030 aims to deliver improved skills in doing more extensive fabric retrofit. I am concerned that the skills required to effectively assess and implement these more extensive measures, and the costs, will deplete a house owners ‘retrofit budget’ to the extent that there is no money left to switch off gas and install a heat pump.

This is also problematic because a householder will rarely implement fabric measures in a single short-term project. In practice it can take many years to implement a wide range of measures; especially where householders are living with the work.

Often, debates on retrofit fail to take account of these real-world issues of limited budgets, extended timelines, and risks of poor delivery of deeper retrofit. Conversely, the challenges of fitting heat pumps are overstated by comparison. We need a much better balance in these debates.

E. Further fabric measures very difficult to justify

A householder installs an ASHP very late after an extensive and disruptive building project:

  • Removing problematic fabric and replacing with energy efficient materials for walls (internal or external), floors and windows;
  • Possibly going below ground floor level at walls to eliminate thermal bridging issues with floor insulation, and;
  • Full external cladding of building, or internal wall insulation;
  • Installs MVHR throughout the house.

These measures would greatly increase comfort and minimise bills. Heating requirements theoretically become minimal (although hot water would still be required, and specialised heat pumps dedicated to hot water are available).

However, in practice, such levels of fabric retrofit are not achievable for hard-to-treat homes at reasonable levels of cost and disruption. And for Britain’s housing stock, this is not achievable on a timescale commensurate with the climate emergency. This point seems to be lost on advocates for deep retrofit.

People talk about the lack of heat pump engineers, but I would argue that training these up is a relatively simple task when compared with the breadth of knowledge required to deal with a large range of historic and current building materials and how to use them in a way that avoids creating problems.

Pragmatic ‘save the planet’ Retrofit

So these are the householder options:

A) Doing nothing on fabric or gas means bills will escalate;

B) Getting off gas early prioritises planet, without bills needing to rise;

C) Further pragmatic fabric measures lower heat demand and bills;

D) More fabric measures reduce bills, but can delay getting off gas;

E) Further fabric measures very difficult to justify.

And for me, concerned about the urgency to limit dangerous global warming, options B or C are the pragmatic way forward in many cases.

‘Insulate Britain! Yes, but by how much?‘ House owners are asking.

‘By enough’ is the answer, and far less than is the received wisdom of those calling for ‘deep retrofit’.

It certainly needs to be at a level that leaves enough in the budget to get off burning fossil fuels. For many or most householders, that means installing an Air-Source Heat Pump [7].

Anything less is not treating the climate emergency with the urgency it requires.

(c) Richard W. Erskine, 2021


[1] ‘Net Zero Carbon Toolkit’ by Levitt Bernstein, Elementa, Passivhaus Trust and Etude,

This toolkit was commissioned by West Oxfordshire, Cotswold and Forest of Dean District Councils, funded by the LGA Housing Advisers Programme. It is licensed under Creative Commons Licence 4.0 International (CC BY-NC-SA 4.0). Licence Deed:

[2] Guide to Heat Pumps,

[3] Consider a householder who spent £25,000 on a new kitchen 7 years ago and is advised that they need to insulate the back wall of the kitchen and the floor. This would require the kitchen to be removed and expensive and disruptive work must be done to accomplish the work, even assuming the kitchen can be refitted. In practice, many of those who do attempt ‘deep’ retrofit do so only over an extended period rather than as a ‘big bang’ project.

[4] Lucien Cook of Savills was on BBC Radio 4’s ‘Your and Yours’ (8-11-21), quoting from research done by Savills, said that to get from EPC D to C, a householder would need to spend £6,500 but would only reduce energy bills by £180 per year (which would take 36 years to break even).

[5] Lawrence Bowles of Savills, commenting on research on valuations of homes:

‘By analysing average values of homes transacted between 2018 and 2020 we found that homes with newer, cleaner, methods of energy demand a much higher price tag. Across England and Wales, buyers purchasing a home with a heat pump fitted are paying on average 68 per cent more for the offer of cleaner energy.’

[6] As the Renewable Heat Incentive (RHI) ceases at the end of March 2022, with a much higher grant for GSHPs than ASHPs, to be replaced (it has been signalled) by an upfront grant with an expected marginal uplift for GSHPs, the likelihood is that the great majority of heat pump installations will be air source (even for the minority of home homeowners that have the land area for laying the slinkies required; and bore holes are even more costly and risky for a single householder to attempt).

[7] For those who live in flats or dense dwellings in towns and cities an ASHP may be problematic because of lack of space for a cylinder, for example (although small systems are being developed). For such case, and for office buildings, low carbon District Heating will often be the preferred alternative, as the Climate Change Committee recognises. But remember that District Heating refers to a heat distribution network, which still needs a heat source. The heat source may itself be a large scale heat pump, such as the water-source heat pump planned for Stroud District Council. Since towns and cities are typically close to rivers or the sea – carrying huge quantities of thermal energy – this is likely to be a popular approach that is already being implemented, to decarbonise heating in many urban settings.


A. Published 8th November 2021: A Progress report on improving Energy Performance Certificates (EPCs) in the UK. This is positive news. The devil will be in the detail, of course, but encouraging.

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Filed under Uncategorized

Is 2°C a big deal?

Alok Sharma, President for COP 26, told a recent meeting:

“Every fraction of a degree makes a difference”

Reported by  Shaun Spiers, Executive Director of Green Alliance UK, on Twitter (@ShaunSpiers1, 5th October 2021.  

Alok Sharma talked powerfully of the real impact of climate change across the world. Richer countries have a moral duty to act, and it’s in their self interest. 

Roger Harrabin, the BBC’s Energy & Environment Analyst since 2004, responded:

“This is such a hard concept to get across. @AlokSharma_RDG is right – every fraction of a degree really does matter. But how to you explain that to the public who may not even take off a layer of clothing for  two degrees?”

I would direct Roger and anyone else seeking an answer to Katharine Hayhoe, who is the supreme master of communication on such questions. Her short video “What’s the Big Deal With a Few Degrees?” answered the question in a very accessible way.

1°C is already big deal

As Katharine Hayhoe concludes, the Earth is already “running a temperature”, and on Twitter said:

“Using our body temperature is one simple and surprisingly relevant analogy. A fever of 2°C has significant, noticeable, and if sustained long-term, dangerous impacts on our health & well-being.”

The Earth System is very complex, and so is the human body. Part of this wonderful complexity is the ability to self regulate. Under normal conditions this manifests itself as a stable system in equilibrium, albeit with minor variations and cycles (such as the seasons and mentrual cycles).

Since the end of the last ice age, the concentration of carbon dioxide in the atmosphere, and hence the global averaged temperature of Earth (not to be confused with weather), has remained remarkably stable, despite large flows of carbon associated with the carbon cycle (which tend to cancel each other out). Human civilisation and its agriculture have emerged over 10,000 years, benefiting from this largely stable climate.

Human emissions since the industrial revolution about 200 years ago have now increased carbon dioxide concentrations in the atmosphere by 1/3rd from 280 parts per million to 414 ppm [1]. This is level is more than at any time in the last 2 million years [2]. 

This is already causing a major disruption in the delicate balance that has existed in pre-industrial times, and we are already seeing the impacts in the increasing frequency and severity of extreme weather events. Each fraction of a degree is important in limiting the damage.

To explain what seems at first to be such a surprising consequence from such a small change is important to realise a few things:

  • the land on Earth is under 30% of the total surface area, and the ocean’s temperature is moderated by the heat capacity of a large volume of water, so land is proportionally more affected.
  • as was predicted in 1967 [3], there is proportionally more warming as you move towards the poles.  This not only warms high latitude regions, but disrupts the jet streams that help drive weather patterns at lower latitudes.
  • the rises in temperature are not evenly spread around the world and in a cruel twist, many regions which are the poorest and least responsible for emissions will face the worst impacts.
  • a shift in the averaged temperature hides a massive increase in the chance of weather extremes.
  • at both extremes of the hydrological cycle (dry regions and wet regions) there is a tendency to magnify these extremes (dry regions get drier, wet regions wetter).
Adapted from Hansen & Sako (2016, 2020)

Even with ‘just’ a 0.9°C increase (relative to pre-industrial, this is a 1.2°C increase) in a global mean surface temperature between the 1951-1980 average, and 2009-2019 average, Hansen and Sako have  shown [4]: 

  • hot summers on land in the Northern Hemisphere already occur twice as often and, 
  • extremely hot summers (like 2003) already at least 200 times more often   

As Katharine Hayhoe explained, a 1°C rise in GMST is an enormous amount of energy. 

The difference between a 1.5°C rise and a 2°C rise is highly significant. The IPCC’s 1.5°C Special Report [5] [6] showed a number of ways in which the impacts of 2°C are significantly magnified compared to 1.5°C:

“At 1.5 degrees Celsius warming, about 14 percent of Earth’s population will be exposed to severe heatwaves at least once every five years, while at 2 degrees warming that number jumps to 37 percent.”

Humanity has left it so late to act that avoiding 1.5°C is now well nigh impossible (according to the IPCC), but we can still decide and act to keep below 2°C, and must avoid the increasingly dangerous higher temperatures.

We are warming very fast

Climate change is happening in a mere flick of the fingers on geological timescale.

Going back as far as the emergence of Homo Sapiens less than 300,000 years ago, the rate of increase in carbon dioxide levels has never been this fast, and the global mean surface temperature has never risen this fast.

It got me thinking about how to articulate why the current rate of change is truly unprecedented.

It is important to note that there is usually an initiating cause of a global warming episode in Earth’s deep past – such as orbital changes that provide the drum beat for ice ages, or even earlier, extreme volcanism. But the main cause of the warming has without exception, since life has existed on Earth, been the release of greenhouse gases. These have been principally carbon dioxide and methane released over thousands of years (short on geological timescales).

Our current situation is quite different for 3 reasons:

  • The initiating cause and the main cause are one and the same: human caused emissions of carbon dioxide from fossil fuels (3/4 of the problem) and emissions of greenhouse gases from agriculture (1/4 of the problem).
  • The period over which this is occurring is an instant in geological terms, just 200 years or so since the start of the industrial revolution,
    • whereas for the exit from the last ice age, it took 8,000 years [8]
    • another analogue to the current fast warming is the PETM (Paleocene–Eocene Thermal Maximum) with an initial burst of greenhouse gases and warming over a period of between 3,000 and 20,000 years [9]
  • Human choices are the ultimate cause, and we can stop it.

Currently we have warmed by about 1.2°C in less than 200 years. 

The rate of increase in carbon dioxide concentrations is a useful indicator of risk, because it is the doubling of concentrations that give rise to an increment of warming of about 3°C. Only by stopping emissions can we stop further warming.

The rise in CO2 concentrations averaged over 200 years is 0.67 part-per-million per year (ppm/yr), which is unprecedented. The PETM higher rate of rise of 0.42 ppm/yr comes close, but the exit from the last ice age is much slower, at a rate of 0.01 ppm/yr.

If we continue on the high emissions path we are on, we could reach 4.4°C of warming (3.3°C – 5.7°C range, relative to pre-industrial) [10]. 

This results from a further increase on carbon dioxide concentrations at a rate of 9 ppm/yr [11], which would far exceed even the upper estimates of the rate of increase during the PETM.

I have summarised all this in the following table.

Rate of change of carbon dioxide concentration currently compared to prior events (Richard Erskine, 2021)

I wonder how anyone can imagine we are not in a climate emergency looking at this table.

(c) Richard W Erskine, 2021.

[correction – I transcribed the wrong numbers from the table to the narrative for duration of PETM pulse – now fixed]

. . . o o O o o . . .


  1. See atmospheric Carbon Dioxide (CO2) levels, 1800–present,  (original sources NOAA and NASA).
  2. The IPCC states “In 2019, atmospheric CO2 concentrations were higher than at any time in at least 2 million years” (in Ref. A, section A.2.1)
  3. Manabe and Wetherald in 1967 published results using the first full model of the greenhouse effect including radiative, convective, and other key aspects, to model the greenhouse effect on earth (Manabe having received a share on the 2021 Nobel Prize in Physics for his contributions)
  4. James Hansen and Makiko Sato published estimates in 2016 (Ref. B). These have now updated in 2020 in, see 
  • Hansen and Sato use baseline 1951-80, which is 0.3°C above the accepted Pre-industrial baseline. So the 0.9°C of warming to date, is equivalent to 1.2°C relative to pre-industrial.
  1. See IPCC Reference C, and and useful summary by NASA, Reference D.
  2. Global Warming of 1.5C, A Special Report by the IPCC 
  3. During a much earlier period in geological history, about 56 million years ago, when the world was already warm and ice free, there was an event that lead to extremely fast (in geological terms) warming. It is called the Paleocene–Eocene Thermal Maximum (PETM). This is described by the IPCC as follows (Ref. A):

“A geologically rapid, large-magnitude warming event at the start of the Eocene when a large pulse of carbon was released to the ocean-atmosphere system, decreasing ocean pH and oxygen content. Terrestrial plant and animal communities changed composition, and species distributions shifted poleward. Many deep-sea species went extinct and tropical coral reefs diminished.”

  1. The Last Glacial Maximum was 23-19 thousand years ago (Reg. A). The current period of interglacial temperatures has lasted 10-11 thousand years. I take 19-11=8 thousand years are the period of exit from the last ice age.
  2. For PETM, numbers taken from IPCC (Ref. A) are: 900->2,000 ppm CO2 (sect; 0.04-0.42 ppm CO2/yr(Table 2.1) and estimate of 5°C (4°C – 7°C  range) globally averaged warming (sect Although a new study (Inglis (2020) suggests greater warming.
  3. The SSP5-8.5 high emissions scenario gives rise to a warming of 4.4°C [3.3°C – 5.7°C range] relative to pre-industrial by 2100 (see Table SPM.1 in Reference A).
  4. Box TS.5 in Ref. A indicates SSP6-8.5 would have cumulative emissions of 11,000 GtCO2. But Figure SPM.7 has 38% of these emissions absorbed by ocean and land/biosphere, so 0.62*11,000=6,820 GtCO2 CO2 remains in atmosphere (for a long time). Now Mackay noted “A useful way to calculate things is to remember that 127 part per million (ppm) of CO2 in the atmosphere equates to 1000 GtCO2”, so 6,820 GtCO2 equates to 6.82 * 127 = 866 ppm CO2. We need to add that to the pre-industrial level of 280, giving a total 1146 ppm CO2. Now, dividing this by 80 years (2020 to 2100) gives 9 ppm CO2 per year on average. Note that this case includes high GHG emissions, but also incorporates a reduced level of take up of greenhouse gases in the oceans, land and biosphere (something that many who criticise this scenario as ‘pessimistic’ fail to grasp).


A. IPCC, 2021: Summary for Policymakers. In: Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Masson-Delmotte, V., P. Zhai, A. Pirani, S. L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M. I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T. K. Maycock, T. Waterfield, O. Yelekçi, R. Yu and B. Zhou (eds.)]. Cambridge University Press. In Press.

B. James Hansen and Makiko Sato (2016) Environ. Res. Lett. 11 034009

C. Global Warming of 1.5C, A Special Report by the IPCC

D. Alan Buis, A Degree of Concern: Why Global Temperatures Matter, NASA, 19th June 2019

. . . o o O o o . . .

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UK Hydrogen Strategy

The UK’s first hydrogen strategy was issued this week. It caused a lot of heated debate.

This is in the context of the latest IPCC Report. Commenting on it Dr Emily Schuckburgh noted in Carbon Brief:

“Ever more certain, ever more detailed. That’s the brief summary I would give the AR6 WG1 summary for policymakers (SPM). Once again it provides a comprehensive chronicle of extreme weather induced by climate change and the risk of catastrophic future impacts. It estimates the remaining carbon budget from 2020 for a reasonable chance (67%) of limiting warming to 1.5C is 400bn tonnes of CO2 (GtCO2). With global emissions in 2020 of 40 GtCO2, this re-emphasises that this decade is critical”.

There is no dispute that hydrogen will play an important role in decarbonising some areas of the economy, especially hard to deal with ones like steel and fertiliser production.

But the report is a little disappointing in sitting on the fence on a number of issues, notably transport and heating, where there is doubt as to the role hydrogen will play. The report says (p. 62):

“Before hydrogen for heating can be considered as a potential option to decarbonise heat in buildings, we need to generate further evidence on the costs, benefits, safety, feasibility, air quality impacts and consumer experience of using low carbon hydrogen for heating relative to other more established heat decarbonisation technologies.”

And (p. 65):

“We recognise that the longer-term role for hydrogen in transport decarbonisation is not yet clear, but it is likely to be most effective in the areas where energy density requirements or duty cycles and refuelling times make it the most suitable low carbon energy source. 

But despite these sensible cautionary words, the report goes on to try and give the impression that domestic heat and transport are still in play, given more research. But are they?

In the area of cars, many car manufacturers have halted or are cutting back R&D on hydrogen fuel cell cars. One of the issues is the relative inefficiency compared to Electric Vehicles (EVs), but building out the infrastructure is another concern.

“You won’t see any hydrogen usage in cars,”

said Volkswagen chief executive Herbert Diess, speaking to the Financial Times, adding that the idea of a big market for hydrogen fuel cell vehicles is …

“very optimistic … not even in 10 years, because the physics behind it are so unreasonable,”

For heating, if we were to use ‘Green Hydrogen’ (created via electrolysis using renewables) to heat our homes, it would require nearly 6 times as many wind turbines compared to directly using the electricity to power heat pumps (which harvest ambient energy in the environment, and so are much more efficient) [1]

The Committee on Climate Change rather highlighted this in their 6th Carbon Budget where they state (for their ‘balanced pathway’):

“By 2030 37% of public and commercial heat demand is met by low-carbon sources. Of this low-carbon heat demand 65% is met by heat pumps, 32% district heating and 3% biomass. By 2050 all heat demand is met by low-carbon sources of which 52% is heat pumps, 42% is district heat, 5% is hydrogen boilers and around 1% is new direct electric heating.”

Or as Professor Cebon said in the Financial Times:

“Hydrogen should be used only as a last resort for sectors that have no option to electrify … Directing public funds towards hydrogen in sectors that have  more effective alternaive solutions is a mistake”.

In other news, Octopus Energy will soon be making a major announcement on heat pumps (they have been teasing the market on Twitter), and are expected to offer a much reduced cost for components and services, to provide a mass market offer. If the Government comes through with an up front grant of several thousand pounds for installation of heat pumps (air source), to replace the Renewable Heat Incentive (which expires in March 2022), this could be a game changer (in terms of mass adoption).

It has been a turbulent week for hydrogen. 

Chris Jackson, chair of UK Hydrogen & Fuel Cell Association Chair has stepped down owing to the Government’s continued support for ‘Blue Hydrogen’ (derived from natural gas, and which involves burying a by product, carbon dioxide, using a method called ‘carbon capture and storage’ that has not yet been proven at scale, but is being pushed by fossil fuel companies like Shell). Chris Jackson said:

“I would be betraying future generations by remaining silent on that fact that blue hydrogen is at best an expensive distraction, and at worst a lock-in for continued fossil fuel use,” 

It feels like the debate over hydrogen will continue, just as it has been for decades, with fossil fuel interests continuing to try to shape the debate in their favour, with arguably far too much influence in policy circles.

In the meantime we need to decarbonise fast, and we don’t have time to waste – just 10 years to put a serious dent in emissions as the IPCC has indicated. Do we really have the time to keep kicking the hydrogen can down the road?

They say the market will decide.

The good news is that for both cars and heating we have electrification solutions (EVs and heat pumps) available, and they are growing in popularity.

Maybe the market already has decided.

(c) Richard W. Erskine, 2021


[1] “Hydrogen: A decarbonisation route for heat in buildings?”, LETI, February 2021,

Figure from the above report. For ‘Green Hydrogen’ we would need a factor of 270%/46% more renewables generation to match the heat provided by heat pumps, that is, nearly 6 times as many off-shore wind turbines operating in winter when we need the heat, for example.

. . o o O o o ..


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Is individual behaviour the solution to climate change?

The short answer is: no and yes.

There is a lot of debate about the role of individual actions in relation to climate change. Allegra Stratton was rightly mocked for suggesting people should refrain from rinsing plates before they are put in the dishwasher. Michael Mann makes a much more serious point, saying that fossil fuel interests – having moved on from climate science denial – are,

“trying to convince people that climate change is not the result of their corporate policies but of our own individual actions” (Scientific American, January 12, 2021)

And of course, Michael Mann does not say that behaviour change is unimportant, but it should not be used to distract us from the much bigger actions that large organisations (especially fossil fuel ones), supply chains and Governments must take.

Whilst others stress the importance of systems change, and the coupled role of behaviour change. Lloyd Alter writes that behaviour change is important:

… because we have to stop buying what the oil and car and plastics and beef companies are selling; If we don’t consume, they can’t produce. It makes a difference; I vote every four years, but I eat three times a day.” (Treehugger, May 11, 2021)

And we have to recognise there are limitations to personal actions when not supported by the system. If I want to ditch the car and take an EV bus to go to work 10 miles away, I cannot do that if there is no EV bus (and maybe no bus at all, at the times I need them).

So, at whatever scale we look at it, and through whatever ‘lens’ we choose, we see the connectedness of actions by individuals, businesses, public institutions, local government, national government and multi-nationals.

I want to show at the scale of a town, how we might think about the power that resides in the hands of individuals; and they can possess multiple persona. Yes, they are consumers, but they are so much more. They are voters, employees, church-goers, parents, children, neighbours, and so much more.

If we break the silence and talk about climate change – not the science but what it can mean in terms of progressive action – it’s amazing how easy it is to start a conversation.

We need to think about the ‘agency’ that individuals possess, within the network of actors in a local community. The influence they have is much more than the narrow framing of consumerism. We see a richer systems view of influence and reinforcing feedbacks, with multiple actors involved, and individuals taking on a variety of personas. Here is a little illustrative doodle I created:

Each of these actors can be self-reinforcing too. The householder can influence a neighbour, just by chatting over the fence (I left out these little looped arrows, to avoid making the schematic too busy).

A climate action group (not shown) can – if it is being effective – engage with all the actors in this schematic by various methods and channels, by networking, engaging, and promoting interactions between them.

For example, holding a fair on house retrofit, and inviting relevant businesses, community groups, councillors and the local member of Parliament. If you don’t ask, you don’t get, my mother used to say!

This does not mean that personal action is unimportant – far from it – but when it can be seen as part of a collective goal to promote changes throughout the system, it is far more powerful. While personal actions today might only impact a fraction of the UK’s carbon footprint directly, indirectly it can have a much greater impact. System change (access to low carbon transport, help with decarbonising heating, etc.) together with personal choices is of course where we need to get to for a high impact on emissions.

The individual will also begin to realise the agency they have to promote not just change, but system change.

(c) Richard W. Erskine

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When does it make sense to switch to a heat pump?

Chris Mason on BBC News at Ten (tonight, on 9th August 2021, the day that the IPCC published the science part of their 6th Assessment Report) stated that (in relation to heat pumps):

“you need lots of insulation to make them work”.

This is completely false: you can heat any building with a heat pump that you can with a gas boiler. Why do BBC reporters keep repeating these myths?

In fact, and in the context of the IPCC report, if one’s main concern was the household carbon footprint, a heat pump would be the first thing anyone would do, as I showed here (given the diminishing carbon intensity of the UK’s electricity grid).

The counter argument commonly used is that the costs of running a heat pump (given today’s unit price for electricity) is unaffordable unless there is huge levels of insulation. Of course if we had a fair fight between gas and renewables, electricity prices would come down relative to gas.

But simple maths shows that even at current gas and electricity prices, if one were to replace an old 70% efficient gas boiler with a modern air-source heat pump (ASHP), then the running costs would not be any greater, with only modest insulation measures, as shown here.

A heat pump can heat any home that a gas boiler can. But it makes no sense to try to heat a barn – with a heat pump or a gas boiler! Insulation and draught reduction make sense – and help improve the comfort of a building – and so ‘fabric first’ is an important message. This leaves open the question: how much insulation a householder considers before they invest in a heat pump?

Depending on how an individual wants to spend their retrofit budget, there will be a cross-over point where acquiring an ASHP will trump any further increment in fabric spending. Adding fabric measures will reduce the size of the heat pump required, but only to a point, as there are some base costs for the system, and we need hot water whatever the state of the fabric.

There are small and large houses, well insulated ones and leaky ones. How do we make sense of the numbers?

A useful metric is the heat energy required to heat one square metre of a home per year (this is measured in kilowatthours per metre square per annum, or kWh/m².a). The average UK house – because our historic housing stock is quite leaky – requires about 130 kWh/m².a. The Association of Environmentally Conscious Builders (AECB) aims, when insulating homes, to reduce this measure to 50 kWh/m².a, although might accept as much as 100 kWh/m².a in the case of (say) a Listed Building. A new build Passivhaus aims to achieve just 15 kWh/m².a.

It is easy to work out what figure currently applies to your house.

Look at your annual energy bills. If heated by gas look at the kWh total for the year. Make a guesstimate for how much of this is space heating, say 80% in the current case. Now divide this figure by the floor area of the home. The question then to think – with the help of a retrofit assessor – how far you can reduce this number.

If you currently have poor loft insulation, then fixing this is relatively cheap and has great pay back. Similarly for cavity wall insulation, and for reducing draughts from doors and windows. You don’t need to rip out your sash windows and replace with double glazing; window brushes, and secondary glazing can make a great contribution with a modest investment. Pragmatism is often required, when assessing where you can get the ‘biggest bang for your buck’.

The other key idea is to think in terms not of ripping out things, but taking opportunities when they arise. So, if a new kitchen is being fitted, then why not use the opportunity to insulate that cold back wall, and maybe even consider underfloor insulation and heating? This is why retrofit can often best be seen as a journey to be followed over a number of years.

What follows is an illustrative schematic showing the balance between the money spent on fabric measures (solid line) and what would need to be spent on an ASHP system at a given level of heat demand. As the heat demand reduces (as a result of fabric spend), so does the cost of the ASHP system (including the heat pump and radiators). The schematic envisages a 4-bedroom semi-detached house with solid walls and poor insulation that is hard to treat, and starts (at the left hand side of schematic) with a terrible figure of 200 kWh/m².a [the numbers are illustrative only – each house is different]:

We then start to move from the left towards the right. Spending even modest money on fabric will mean that the size (and cost) of the heat pump system you might buy progressively reduces (e.g. there is a big drop if one moves from a cascade heat pump system to a single heat pump).

At some point, the marginal cost of incremental insulation will rise above the cost of an ASHP (when the solid line cross the dashed line). For example, replacing all the windows with double or triple glazing is a non-trivial expenditure.

And of course, to try to turn a leaky Victorian house into a Passivhaus makes little sense, so there are natural constraints in how far one goes, depending very much on house and site specific factors.

Some people may decide to adopt the ASHP early for a number of reasons (they need to replace an old gas boiler and care about the climate future, or they live in a house in a conservation area where measures like external wall insulation will not be accepted). They may live on a terrace and external wall insulation for one house without the whole terrace joining in, would meet a lot of resistance (including from the planning department). For whatever reason they make their choice, I call these, ASHP ‘eary adopters’.

On the other hand, they may live in a house that can absorb a lot of retrofit insulation measures – perhaps as new owners wanting to start with a ‘blankish’ canvas – and with the help of a retrofit assessor/ expert, strive to get to the AECB 50 kWh/m².a figure. Let’s suppose they don’t have constraints such as conservation issues to deal with. We might call them ASHP ‘late adopters’.

In practice, householders will be somewhere on a spectrum between these two example – in a decision spread zone. A whole set of factors may come into play in their decision making: wish to improve comfort, or reduce carbon emissions, or concern over gas prices in the future, to name just a few.

It therefore makes no sense to say “you need lots of insulation to make them work”.

No, you need “a sufficiency of insulation” to make the running costs “fit your expectations”, and everyone may arrive at different expectations.

But don’t try to heat a barn, with a gas boiler or a heat pump.

(c) Richard W. Erskine, 2021.


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Fantasy maths from the National Farmers Union

Soil carbon is important but it is staggering that both Minette Batters and Prince Charles have made unchallenged statements on @BBCr4today (14th July 2021): That some (livestock) farms are already carbon neutral and that soils could take up 70% of the world’s emissions.

This is all in an effort to promote sustainable livestock farming. Like Graham Harvey in his book ‘Grass-Fed Nation’ they have been seduced by the claims of Allan Savory; but these have been thoroughly debunked by the Food Climate Research Network (FCRN)

The fallacy rests on a confusion between fast and slow carbon cycles, between carbon stocks and flows, which with a little bit of naive maths creates a myth that now permeates the NFU’s PR on the future of farming.

We need better soil health to reduce net carbon release in a warming world, but it is no good using this as a ploy to retain high levels of meat consumption; and we need a massive reduction in the consumption trend.

Godfray et al [1] show the path we are on:

Good soil health will help create sustainable arable farming, but not as a silver bullet to cancel our fossil fuel emissions. Massive reductions in meat production mirrors the same reversal that is needed in all sectors of our economy, and it is a fantasy to suggest otherwise.

Efficient land use is also an issue. Today, over 50% of the UK’s land is devoted to livestock (and this does not include the foodstock we import to supplement their diet), and we import over 40% of our food. To be more self reliant, we have to make a radical shift in diet and land use, as the Centre for Alternative Technology clearly demonstrates in their report Zero Carbon Britain: Rising to the Climate Emergency from which the following Figure is taken:

Livestock reduce the efficiency of calories produced per hectare [2], which is a major issue when it comes to feeding the world.

In the context of the climate emergency, the other issue is that livestock makes a high and increasing contribution to our carbon emissions [1]:

Trying to hide these emissions amongst some warm aspirational words about regenerative livestock farming in idyllic English countryside, is pure delusion (as well as being heavily funded PR), with no scientific basis.

It is such a shame that the NFU (National Farmers Union) are promulgating junk science to advance their meat-first agenda, and it seems that Prince Charles is also on board. 

. . . o o O o o . . .

Science references:

[1] Godfray et al., ‘Meat consumption, health, and the environment’, Science 361, 243 (2018)

[2] Cassidy et al., ‘Redefining agricultural yields: from tonnes to people nourished per hectare’, Environ. Res. Lett. 8 (2013) 034015

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My First Oil

Having worked with acrylics, watercolours and pastels for some years, I decided, finally to take the plunge and start to use oils. The scene is the view across to the River Severn and Wales from Selsey Common.

I’m still pinching myself that I managed to pull this off. 

The foreground gave me the heebie-jeebies.

Grasses were quite straw like with subdued green, and there was lots of undulations.

I remembered to use a little red to ‘knock back’ the greens, and then added combo of yellow ochre and white to progressively lighten it; and some raw sienna in the other direction (to darken), maybe a smidgen of red too in places.

Also, some slightly larger brush strokes in the foreground to suggest more resolved grass.

I remembered to ‘think tonally’ to observe and think about light and dark – there was a huge range to cope with here. I used some Prussian Blue to help with the deep shadows.

The distant fields was just a kind of noodling around trying to get a sense of distance – so cooler, more muted and less defined the further away.

Wales is just a light purple sliver beyond the Severn, which itself is just a hint of reflected light.

The two fields on the right were compositionally crucial to me as they helped establish a near-ground scale beyond the foreground.

Some flecks of white on the mid distance right for buildings – never forgetting the power of gestalt to allow the viewer to see what their mind reconstructs based on the tiniest of visual clues.

The sky was a struggle – I miss the dynamism of working with acrylics or watercolour, so need to practice my skies – but the good thing is that the dark clouds suggest a darkening of the distant land below, and the few yellowy green bright streaks suggestive of sun breaking through on some fields. A little green in the sky is another fully transferrable trick of the trade.

The foreground is in full sun with slopes facing the sun almost white.

The pros of oils are also the cons.

You can keep fiddling for days if you want (although I finished this over 5 hours on and off); so blending on canvas, and wiping away sometimes, is all possible. Acrylics allow for multiple layers and drying in between, with spraying and all sorts of jiggery-pokery; but the palette needs constant attention to stop it drying out. I think they are both wonderful – its like trying to choose a favourite dish – why choose?

I think I’m going to fall in love with oils … just like I did before with acrylics, watercolours and pastels!

(c) Richard W. Erskine, 2021

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Are Air Source Heat Pumps (ASHPs) a Silver Bullet?

According to the Committee on Climate Change heating our homes makes up 40% of our energy use and 20% of our carbon footprint. While there have been dramatic improvements in building standards since 1970 there remains a legacy of poorly insulated homes.

Retrofitting our often old housing stock to reduce heat loss is crucial, but we also need to stop using natural gas as the source of heating if we are to have any chance of meeting our goal of halting global heating. 

It got me thinking about this question – if someone asked about retrofitting their house, and was motivated by the desire to reduce the carbon footprint of heating their home: 

what is the first thing they should do?

It may seem a somewhat artificial question, because in any real world situation, several measures are likely to be advisable, but bear with me.

Many retrofit professionals repeat the mantra “fabric first”, which means, focusing on insulating the building, dealing with leaks, and so forth. This sounds like good advice, given that the cost of some measures, like insulating a loft, are relatively cheap and deliver big savings in carbon emissions.

However, in many cases this is expressed in stronger terms, like “deep retrofit”, which can mean doing everything possible to reduce the heat loss of a building. This could include external wall insulation to homes with solid walls (which cannot benefit from cavity wall insulation), new windows, and dealing with associated issues related to moisture, for example. This school of thought suggests that we should only consider using a heat pump after deep retrofit is complete [Note 1]. 

The mantra “fabric first” then effectively turns into fabric only, because it is not difficult to exhaust a householder’s retrofit budget with changes to the fabric of a building. 

So why should we be considering heat pumps alongside changes to the fabric of a building? 

A heat pump harvests the ambient energy outside a house – either from the air, the ground or water. This ambient energy comes from the sun (when the ground is used as a source it is never deep enough to harvest energy from the core of the Earth, even with a bore hole, and is simply extracting energy from the ground that has been warmed by the sun and stored there). 

For every unit of electrical energy put in to drive the heat pump, it is able to deliver at least 3 units of heat energy into the home. A nice simple explanation of this process is provided here.

Professor David Mackay wrote in his seminal 2010 book Sustainable Energy without the hot air (p.151):

“Let me spell this out. Heat pumps are superior in efficiency to condensing boilers, even if the heat pumps are powered by electricity from a power station burning natural gas. … It’s not necessary to dig big holes in the garden and install underfloor heating to get the benefits of heat pumps”

He was calling for the adoption of Air Source Heat Pumps (ASHPs). He didn’t use the words ‘silver bullet’ but it is clear he was a big fan and frustrated at the low level of take-up. As he wrote 

“heat pumps are already widely used in continental Europe, but strangely rare in Britain”.  

I thought about how to present some information to help explore the question I have posed, and compare fabric related measures to an ASHP. I took data from the Energy Saving Trust website for a typical semi-detached house and plotted the capital cost of different interventions against the annual carbon saving that would result.

The capital costs are indicative and include the parts and labour required.

The only change I made to the Energy Saving Trust data was I reduced the savings for an Air Source Heat Pump (ASHP) from about 4.5 tonnes of CO2 to about 3, because that better reflects the carbon intensity of the national grid in the UK in 2020.

I also indicate the level of disruption involved with colour coding, because this can be a factor in a householder’s decision making. The graph is based on the data tabulated in the Table at the end of this essay [Note 4] (click on image to see higher resolution):

This householder is aiming for the highest carbon saving, and there is only one answer glaring out at you from this graph: the ASHP.

If I change the question slightly we get a more nuanced answer:

what is the first thing they should do, based on carbon reduction ‘bangs for your buck’?

The ratio of the annual carbon saving to the capital cost is a measure of ‘bangs for your buck’.  On this criterion, it makes sense to do the low hanging fruit of loft insulation and fixing drafts, but then once again the ASHP scores very well (this allows for the fact that typically more than half the radiators will need to be upgraded [Note 2], and are included in the cost estimate).

Whereas external wall insulation would typically be similar in cost to an ASHP, but deliver only a third of the annual carbon saving and be a much more disruptive intervention; and in many cases not one that is practical to implement.

A counter argument would be that if we did manage (for a solid walled home) to do all the fabric related measures, we would achieve about 2,400 kgCO2/yr carbon saving (over half the current emissions of 4,540 kgCO2/yr) for an outlay of about £18,500; and then the ASHP could be added and would then ‘only’ need to deal with the remaining half, and that could mean that a lower capacity heat pump could be installed, reducing its cost somewhat.

Each situation will be different and depend on what interventions are possible. If a building is listed and external installation is prohibited (and the alternative of internal insulation dismissed), then the fabric related measures would then total 1,500 kgCO2/yr, leaving two thirds of emissions to be dealt with. 

In either case, in order to maximise the emissions reduction one would require a heat pump.

My argument is not that you must fit a heat pump first, but that you should consider all the available options and to think about a plan (possibly over a number of years). 

I went on to plot another graph where I included the following additional features:

  • To show the ‘best’ reasonable case fabric interventions (which would raise the cost of say, wall insulation, but at the same time increase the carbon saving). 
  • To include a Ground Source Heat Pump (GSHP) option, either with horizontally laid slinkies, or using vertical bore hole(s).
  • To show what happens as the UK electricity grid moves from 2020 carbon intensity levels to being 100% green.

The following illustrative graph was the result:

There are a number of interesting observations based on this graphic.

  • Firstly, as the arrows show, we can increase the carbon savings for each fabric related measure, but these improvements come at extra cost. There will be some trade off for each householder situation as to how far they can go.
  • Secondly, once you have a heat pump, the annual carbon saving will increase every year as the grid gets greener (as it has been in the UK), without the householder having to lift a finger.
  • Thirdly, while a GSHP may have a better performance than an ASHP, it is likely to be quite limited [Note 3], and as Paul Kenny said in his talk to Carbon Coop ‘Heat Pumps – Learning and experiences from Ireland’, if you have extra money spare, why not do the easy thing and spend it on further upgrades to radiators, when you can achieve a target COP without the major disruption and risks associated with a GSHP project (assuming that is even an option).
  • Fourthly, a borehole GSHP is even more costly, and more risky. There are significant risks associated with, for example, drilling into water tables, but the real killer is the cost. For a single householder it makes little sense. Of course, one can imagine scenarios where several houses could share the costs, but these are likely to be exceptional projects; not the basis for mass roll-out of heat pumps.

Some will argue that an ASHP requires supplementary heating during very cold spells in winter. However, in the same talk referred to above, Paul Kenny used data from a significant number of retrofits in Ireland that had ASHPs, using a design parameter of -3°C for cold winters. When the beast from the east came and these houses experienced -6°C, they were all fine and did not require supplementary heating. He wrote a piece on LinkedIn about this experience, which flies in the face of much of the ‘received wisdom’ in the retrofit community.

And in the UK, without the much larger grant that GSHPs enjoy, as compared to ASHPs, it is doubtful there would be anything other than a marginal role for GSHPs. It will be no surprise if ASHPs dominate the heat pump market in coming years and for some installers, this is already the case.

So, are Air Source Heat Pumps a silver bullet to decarbonising the heating of homes? 

One has to say in many ways they are!

But of course, in reality, it makes sense to consider them in the mix of other retrofit measures, and to carry out some improvements to the fabric of a building as part of a ‘whole house’ plan.

We just shouldn’t let the ‘deep retrofit’ mantra put people off considering an ASHP; maybe even as one of the first things you do.

(c) Richard W. Erskine, 2021


1. While I am a huge fan of PassivHaus and similar standards, we must remember that these standards cannot easily be applied to existing stock, and would be hugely expensive. 80% of the homes in 2050 already exist, so 80% of the problem of decarbonising heat in homes is already there; and BRE estimates there are 9 million ‘hard to treat’ homes in the UK.

2. Upgrading radiators is usually required to increase the effective surface area. This is needed because heat pumps operate at a lower flow temperature, and the heat delivered is a function of the temperature of the radiator and its surface area. The surface area can be increased by using 2 or more panels with fins sandwiched between them. This can also help reduce height and width of the radiator that would otherwise be necessary, while making the radiator somewhat deeper / fatter.

3. A GSHP has a better Coefficient of Performance (COP) in winter, an ASHP could do better in Spring and Autumn. The overall Seasonal COP for a GSHP will probably be higher but unlikely to be higher than 15%. We need real world studies to get a good figure here. But the cost of a GSHP using slinkies in 1.2m trenches (for those unusual cases where householders have sufficient land to achieve the area necessary) is something like double that for the ASHP. 

4. Table of Typical three bedroom, solid walled, semi-detached house


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Small Is Beautiful – local renewables and storage can catalyse the greening of grid

Governments of all shades, and energy utilities, tend to believe that large, centralised solutions are the most cost-effective because of the economies of scale. There is a belief  that local solutions will increase costs. 

Ground-breaking work by an energy modelling company in the USA (Vibrant Clean Energy (VCE)) has turned this argument on its head, and this could, or should, have profound implications for any strategy to decarbonise the power grid in any country, including the UK, with renewables playing a dominant role in the future.

VCE summarise some key conclusions:

The present study finds that by including the co-optimization of the distribution system, the contiguous United States could spend $473 billion less on cleaning the electricity system by 95% by 2050 and add over 8 million new jobs. … The findings suggest that local solar and storage can amplify utility-scale wind and solar as well as provide economic stimulus to all regions across the contiguous US.

The study finds that wind, solar, storage and transmission can be complements to each other to help reduce the cost to decarbonize the electricity system. Transmission provides spatial diversity, storage provides temporal diversity, and the wind and solar provide the low-cost, emission-free generation.

We understand that what is true for USA can be true of the UK. 

Now, in the UK, various groups have already published reports based on modelling of the grid to show that net zero is achievable. The Centre for Alternative Technology (CAT) produced a report ‘Zero Carbon Britain – rising to the climate emergency’ that showed how this could be achieved. They used granular weather data to help model supply and demand at national scale. Energy storage was included at utility scale (using excess energy on windy/ sunny days to produce synthetic gas that could be used to generate electricity during periods when both wind and solar were too low to meet total demand).

VCE have gone much further in the sophistication and granularity of the modelling:

  • Firstly, they have modelled the dynamical behaviour of the grid at all scales – with 5 minute intervals and 3km square spatial grid over a minimum of 3 calendar year (and for planning reserves up to 175 years hourly at 30km grid). There was always a suspicion with other models that even if the national supply and demand appear to match up at a point in time, the grid will experience issues at particular points in the grid, particularly at local pressure points. VCE have addressed these weaknesses.
  • Secondly, the economics of how the roll-out of the capacity is achieved is key to policy. The modelling includes economic aspects to show the marginal cost of each new tranche of generating capacity; and so modelling the evolution of the network, not just an assumed end point. VCE have modelled the period between ‘now’ and future end dates to see what impact different scenarios have on the marginal and net costs. 

The astonishing result that VCE have found is that local renewables with local storage – even at only 10% of the total generating capacity – make a disproportionate impact on the speed and cost of further roll out of associated utility scale renewables. This is because it creates flexibility in the grid and relieves pressure points.

VCE note that this was an emergent behaviour of the system, which the modelling revealed, and certainly not obvious to energy specialists, because its only emerges when the model reaches a sufficient level of sophistication. 

The bottom line is that we should see local renewables (including community energy schemes) not as marginal additional capacity in the transition to a greening of the grid, but as a key ingredient to both speed up – and lower the cost of – the transition. We should see small and big as beautiful, working collaboratively, to accelerate the greening of the grid.

This may seem quite a technical point for those who are not students of the energy system, but it is truly remarkable and transformative, and from a policy perspective, it highlights the need for Governments to continue to promote and invest in large, utility scale renewables, but also to assist in the roll out of local renewables and associated storage.

UK Treasury, please take note!


“Why Local Solar For All Costs Less: A New Roadmap for the Lowest Cost Grid”, Vibrant Clean Energy (VCE), December 2020, 


VCE define emergent behaviour as follows:

Emergent behavior is characterized by properties and behavior that is not dependent on individual components, but rather the complex interactions and relationships between those individual components. Therefore, it cannot be fully predicted by simply observing or evaluating the individual components in isolation.


Filed under Renewables, Transition to Low Carbon

Nuclear weapons and me

Remembering Hiroshima – the dead, the survivors and the blight that nuclear weapons have brought on this world – on this day, 75 years after the first nuclear weapon was used against a civilian population. A weapon, remember, that was developed because of a fear that Nazi Germany would develop it.

Joseph Rotblat, a scientist who I admire so much, left the project to develop a nuclear weapon when it became clear to him that Germany would not be able to develop it. Few if any others on the project possessed his moral vision and authority.

In 1981, Professor Mike Pentz, who led the formation of the OU (Open University) science department, founded Scientists Against Nuclear Arms (SANA). I was at Bristol Uni. doing a Post Doc at the time.

I went to hear him speak. What an amazing and inspiring speaker he was; I signed up on the spot. The cruise missile crisis was in full swing.

Within months it seemed I was on the National Coordinating Committee of SANA.

It kind of killed my passion for science, something I’d been in love with since a young boy. I had a lab when I was just 12.

I left my research in computational quantum chemistry.

I went into the world of industry and in my spare time spent a lot of the 80s working in the background helping to develop tools for the anti-nuclear movement.

This included a Program to assess the impact of nuclear attacks, which I managed to squeeze onto an Amstrad PCW 8256 – with no hard disc and a memory of just 256K! Or 0.25Mb, or 0.00025Gb.

This program was given free to local authorities. 

During this time I had also married the beautiful nurse who I met in Bristol, and we brought up two girls. So Bristol always has a special resonance for me, on so many levels.

Eventually I was pretty burnt out and stepped back from nuclear activism – after all, we got rid of cruise. Job done, right?

If only.

SANA evolved into SGR, Scientists for Global Responsibility, a great organisation that is still going strong and doing good work.

Nevertheless, it might explain why it took a while for me to realise there was another great elephant in the room – global warming. 

This time, it was Naomi Klein, and specifically her book This Changes Everything which was the kick up *** I needed. I have a signed copy from when she spoke at the Cheltenham Book Festival.

Now I spend a lot of my time in retirement on climate change matters, but focusing my efforts on local community action.

I never lost my love for science, even if things turned out different to my boyhood dreams.

But damn you, nuclear weapons, and damn you fossil fuels, and you, the same old, same old vested-interest apologists.


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Angry Weather

Dr Fredi Otto is the Acting Director of the Environmental Change institute and an Associate Professor in the Global Climate Science Programme where she leads several projects understanding the impacts of man-made climate change on natural and social systems with a particular focus on Africa and India.

Her new book, Angry Weather: Heat Waves, Floods, Storms, and the New Science of Climate Change published by Greystone Books is due out on 17th September in the UK (and 2 days earlier in USA), and I for one, can’t wait to read it.

She was interviewed about the book in The New Scientist

Credit: Rocio Montoya

Here’s a short review by Kirkus.

The attribution work Dr Fredi Otto has helped pioneer is extremely important and here’s why …

We need to be able to move beyond the general global trends that have tended to dominate the conversation on climate change. These demonstrate beyond doubt that human greenhouse gas emissions are the dominant factor in creating a warmer world, where extreme weather events are an expected outcome.

What has been harder to assess is the ability to pin a particular extreme weather event on man-made global warming.

I am hoping that this book will help me – and maybe you? – on a journey of discovery, to learn more about advances in our understanding of how to make that link (I am ordering my copy through my local bookshop The Yellow Lighted Bookshop, not Amazon, because (a) I support local businesses whenever I can and (b) YLB are just brilliant!)

In a previous era when smoking and lung cancer cases first began to appear in the courts, the tobacco companies would use the defence that nobody could be sure if this or that particular case was due to smoking or would have happened anyway. It was just bad luck!

No matter that the bad luck was rising exponentially amongst smokers.

The fossil fuel companies can and will use the same cynical defence.

Sir Richard Doll and collaborators did pioneering work to demonstrate the link between smoking and lung cancer in 1950, using novel statistical methods to overcome the charge that ‘correlation does not mean causation’. In this case it most certainly did. Remember, that this long ago, the underlying biochemical mechanisms were not that well understood, and it was 3 years before we had even the basic structure of DNA established, in that seminal year when I was born 🙂

So, climate attribution science – the ability to pin man-made climate change on particular extreme weather events – is a complete game-changer.

The advantage here is that the underlying physical mechanism are extremely well understood, relying on 200 years of accumulated fundamental science. No need here for any new fundamental physics.

But once again, statistics is the hurdle that must be overcome.

Because while at a global level, the uncertainties as to the human causation for global climate change have now essentially decreased to the point where humanity’s fingerprints are all over man-made global warming, as one gets to smaller and smaller scales, the uncertainties mount up, for quite basic statistical reasons.

Once again, innovations are required in order to demonstrate the link at the level of a Hurricane Sandy, or the recent extreme Australian Fire season.

But imagine the implications of being able to make these connections.

We would then be in a position to hold businesses and politicians to account for their inaction, and put a price on the consequential damage, at least in the narrow sense of the quantifiable impact on property; something they at least understand [1].

As Dr Otto says:

“If governments don’t do their job and don’t do enough to put a stop to climate change, then courts can remind them of their purpose.”

So, far from being about some dry technicalities regarding climate attribution and statistical analysis, this book could become part of the tool-kit of everyone involved in action to limit the extent and severity of man-made global warming.

I really hope it does.

(c) Richard W. Erskine, July 2020


[1] It is tragic that we seem – at least in the Anglo-Saxon culture – to put so much more weight on loss of property than loss of habitat or life even, but that bias can be turned to our advantage.

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The Green Electrification Sceptic

I have had a number of conversations over the last few years with friends and associates working in climate and green groups who are sceptical about the focus on electrification in decarbonising our energy. They are, for want of a better phrase, green electrification sceptics. 

They will argue that only massive reductions in the consumption of energy is the way forward, while of course they agree that we should stop using fossil fuels and are not opposed to electrification per se.

They are neither climate deniers nor renewables deniers (those two being birds of a feather). But they do represent a significant strand of opinion that believes the UK electricity grid won’t be able to cope, within the required timescale, with the demands of transport (Electric Vehicles) and heating homes (using Heat Pumps), because of the huge amount of energy we currently use nationally in the form of gasoline and natural gas.

They would instead argue for a modal shift towards walking and cycling, and public transport and – for many homes – deep retrofit. This should be the focus they would argue, instead of trying to do the same things we do today – with all the wasted energy that involves – and try to decarbonise that.

Well, I agree with this sentiment. 

Driving a few miles to a shop to get a loaf of bread when we could have walked or cycled; heating our homes with gas boilers with upstairs windows half open; and all this with no price paid for the damage done by our carbon emissions.

It’s crazy and I agree with that.

However, people do need to move around, and for some in rural areas at least cars are unavoidable, even with improved public services. We certainly should not need 30 million cars in the UK in 2050 or even 2030, but zero is also not the right answer. And we need to heat our homes in winter, and we are not going to apply PassivHaus levels of retrofit to the (according to BRE) 9 million ‘hard to treat’ homes in the UK – at least on that timescale. We need a plan, and the numbers that back up the plan must have a sound basis.

This is where I want to challenge green electrification sceptics, because I see a tendency to bolster their arguments with information that doesn’t stack up. This helps no one, because it doesn’t get us to a realistic plan we can all work towards. And we need to scale up whatever we do pretty damn quick, with solutions that we already have to hand (techno-futurism is a tactic used by the denialists to delay action, and we shouldn’t fall for it).

A Typical Argument

The following figure is from the July 2017 issue of Energy Consumption In the UK from BEIS, and used for illustrative purposes only. 

BEIS 2016 energy equivalents

Electricity in 2016 was about 20,000 ktoe (Kilotonnes of oil equivalent – a unit of energy) and (natural) gas plus petroleum was about 150,000 ktoe. 

So, the argument goes, we’d need to increase the electricity energy generated by at least 7 times to displace the gas and petroleum, and this doesn’t sound feasible by 2050 let alone 2030 (the date that many local authorities in UK are committing to getting to net zero in these sectors). 

My Response

The basic issue here is confusing primary energy, shown on this graph, with delivered energy, and this overstates the amount of electricity that would need to be generated to displace the fossil fuels shown.

‘Primary energy equivalents’ includes not only the delivered energy, but any energy lost as part of the transformation from one form (e.g. gas) to another form (e.g. electricity) of energy. 

But there are other factors to take into account when considering the feasibility of electrifying transport and heat. I have listed them here, and they fundamentally change the basis for any debate regarding the electrification  of transport and heat in the next few decades:

  1. Primary energy equivalents: For fossil fuels these shouldn’t be used as measures of the energy required in a transformed system, without appropriate adjustments.
  2. End-Use efficiency factors: Inefficiencies of internal combustion engine (30% efficient) compared to a EV (90% efficient); see Note 1.  Heat Pump (typically 300% efficient) is also at least 3 times as efficient as a gas boiler (90%), again meaning a reduced demand to do the same job; see Note 2.
  3. Modal changes: By doing more to get people out of cars (as the new Decarbonising Transport report from UK Gov’t calls for) – walking, cycling and more use of public transport – we can reduce energy required for travel.  Reduced consumption and electrification are not mutually exclusive..
  4. Smoothing / lowering peak demand: On the consumption side at grid scale, there is lots that can be done to lower and smooth demand. For EVs, smart charging means we can eliminate large peaks in demand. For buildings, off-peak water heating means less wind turbines to do the same job.
  5. Energy storage / flexibility: Comes in many forms, including electrical (batteries), thermal mass (e.g. hot water tanks), pumped storage, etc. – EV cars can become part of the solution, rather than the problem, by helping to build a flexible and adaptive network at local and national scales.

These factors together mean that instead of 7 times more electricity energy per year for a future UK it would be much less than this. Even if we carry on doing more or less the same things, it would be 2.7 times more according to David Mackay (see Note 3). 

If we adopted the level of modal shift and retrofit proposed in the Centre for Alternative Technology’s ZCB scenario (Zero Carbon Britain), then we could reduce annual demand for energy by 60%, including an 80% reduction in the energy required for all forms of transport (cars, buses, planes, etc.) (see Note 4).

With Covid-19, but even before, there were many questioning why someone needs to do a 100 mile round trip for a 40 minute meeting. The digitisation of many sectors of the economy can make a big dent in the need for journeys – by any means – in the future.

And on heating our homes we can reduce our energy demand by 75%. I’ll let David Mackay do the talking (p. 153):

… can we reduce the energy we consume for heating? Yes. Can we get off fossil fuels at the same time? Yes. Not forgetting the low-hanging fruit – building-insulation and thermostat shenanigans – we should replace all our fossil-fuel heaters with electric-powered heat pumps; we can reduce the energy required to 25% of today’s levels. Of course this plan for electrification would require more electricity. But even if the extra electricity came from gas-fired power stations, that would still be a much better way to get heating than what we do today, simply setting fire to the gas. Heat pumps are future-proof, allowing us to heat buildings efficiently with electricity from any source.

Further thoughts on EVs

At this point, the Green Electrification Sceptic might say…

Ok, I see what you’re saying, but charging all the cars (that will remain at current levels for some time) is still going to need a massive increase in generating capacity, to deal with the peak load

This was essentially the argument given by an article in The Times (Graeme Paton (11th February 2017) ‘Electric cars mean UK could need 20 new nuclear plants’). 

The flaw in this argument rests on the assumptions that everyone is charging at the same time, but in reality the load can be spread, lowering the peak demand. Nationally, 73% of cars are garaged or parked on private property overnight, according to RAC Foundation. Utilities are offering deals to help them to do smart management of the grid, offering customers some perks for signing up to these win-win deals. You just tell the service provider via your charging App you want to be charged by 7.30am tomorrow morning and the software decides when to schedule you. So the peak demand will be considerably less as a result, and in fact, EVs with their batteries then become part of the solution, rather than the problem. And the charging infrastructure need not be the hurdle many assume it to be with most charging occurring at home. EVs will actually help create the flexible and adaptive grid we need in the move to renewables.

A McKinsey report on The potential impact of electric vehicles on global energy systems, concludes that the expected uptake of EVs globally is entirely manageable, assuming the relatively simple measures such as load shifting and smart charging we have discussed are deployed.

However, as a society we are still too obsessed with cars. Fetishising cars needs to end. A large EV SUV is still using a lot more resources and energy than would be needed by someone able to use regular and affordable public transport (say an EV bus), or a bike (electric or not). There is an issue of fairness at work here too, for the many people who cannot afford an EV, even a small, less resource hungry one.

Having an expensive EV car sitting mostly idle is not a great solution either, because it fails to maximise use of resources. 

In the future, people imagine autonomous vehicles which would remove the need to even own a car, and instead we would have a ‘car as a service’ via an App on your phone, which could mean we need many fewer vehicles (but maximising their usage) to cover the same miles required (the cynic might say “isn’t that a taxi?” – yeh, but minus the human driver). 

For cities, it is already questionable whether people need a car; many don’t bother because of the hassle. 

This not the case in the rural setting, so car ownership will not end anytime soon, but we need to have a major investment in public transport, cycle lanes, and cycle infrastructure in general – and policy measures like dynamic road pricing – to nudge people out of cars, as part of a comprehensive approach to decarbonising mobility and transport.

Further thoughts on Heat Pumps

Gas boilers and a lack of any charging for the damage caused by carbon dioxide emissions have encouraged a culture of flagrant wastage of energy in the UK. Someone with a house with a 6kW heat loss might typically have a 20kW gas boiler, so it can be heated in no time, even while windows are left open! 

This is our instant gratification – ‘I want it now’ – culture. 

There is no imperative to insulate the home because of artificially low gas prices (which of course will sky rocket in the future, just you wait and see).

It is the kind of attitude that ensures that when heat pumps are installed to replace gas boilers without any serious attempt to educate and monitor behaviour, the nameplate performance will be ruined by people continuing to try to heat the town as well as their homes, or oversize the heat pump and also end up killing its measured coefficient of performance (COP).

David Mackay wrote the following about heat pumps in 2009 (p.151) (see Note 5):

Let me spell this out. Heat pumps are superior in efficiency to condensing boilers, even if the heat pumps are powered by electricity from a power station burning natural gas. If you want to heat lots of buildings using natural gas, you could install condensing boilers, which are “90% efficient,” or you could send the same gas to a new gas power station making

electricity and install electricity-powered heat pumps in all the buildings; the second solution’s efficiency would be somewhere between 140% and 185%. It’s not necessary to dig big holes in the garden and install underfloor heating to get the benefits of heat pumps; the best air-source heat pumps (which require just a small external box, like an air-conditioner’s) can deliver hot water to normal radiators with a coefficient of performance above 3.

But people still seem to think it’s magic, and myths abound around heat pumps and especially Air-Source Heat Pumps (ASHPs) …

… they don’t work on older, larger homes

… they don’t perform well in cold spells

… they are really noisy

… you’ll need deep retrofit to Passivhaus levels to make it worthwhile

All untrue. But people have had bad experiences due to a combination of poor assessments, poor installation and tuning, and poor operation. 

The more insidious issue with heat pumps is that people think it’s magic that you can apparently heat a house with cold water or air. The BBC’s record on reporting heat pumps is dismal (see Note 6).

Now, because only a minority or householders have a water or ground source sufficient to heat their homes, so the assumptions is that we would expect the great majority of homes to use air-source heat pumps (ASHPs).

The ‘Green Electrification Sceptic’ will say they understand how heat pumps work, but then repeat some of the myths around ASHPs and say that the Seasonal Coefficient Of Performance (SCOP) – the COP averaged over the year – is not the oft quoted 2.5 for ASHPs, but 2 or even lower. What I think this reflects is bad experiences based on poorly installed or operated systems. This bad experience – in some cases dating back years – is being used as a reason to reject ASHPs.

I attended an excellent webinar hosted by Carbon Coop from Paul Kenny, former CEO of the Tipperary Energy Agency who conducted a pilot, including many homes (working with the Limerick Institute of Technology to assess the results).  The video recording is here  and his slides are here. These were all ASHP installations.

During a period of October 2017 and May 2018 the overall COP ranged from about 2.6 to 3.6 and averaged 3.1, pre-optimisation. During an exceptionally cold 2 week period, where external temperatures were down to minus 6oC, the COP was never below 2.5 and ranged from 2.5 to 3.

Key points to note:

  • They did necessary and sufficient retrofit but not to a Passivhaus standard.
  • There was no external wall insulation, for example.
  • They did not upgrade 2 panel radiators to 3 panels. They did pragmatic emitter upgrades.
  • When asked whether it was worth going for a Ground-Source Heat Pump (GSHP) because of extra nameplate SCOP, Paul Kenny said no, because if one has some extra money, they should spend them on upgrading emitters (e.g. get those 3 panel radiators), and you can close the performance gap without the disruption of digging up an area of garden (assuming one has that option, which many won’t have).

It is a very positive story of how to make ASHPs successful (and, btw, Carbon Coop are a great source of material, sharing real-world experiences of whole house retrofit).

He does caution that one needs a properly qualified assessment done, and ‘sufficient’ remedial retrofit is obviously required. But properly sized and installed, there are really no issues using the approach they have now refined. Every house is different, but the ingredients are the same.

He cautions also against oversizing a heat pump (and I think the combination of EPC (Energy Performance Certificate) and RHI (Renewable Heat Incentive) may push this outcome sometimes, by being pessimistic about the achievable SCOP), because then they may well be kicking in and out of operation, and this will kill their measured COP.

Increasingly we are seeing ASHP and PV combos (see some examples from Yorkshire Energy Systems here) because, while the peak need for heat and minimum for solar PV coincide in the year – hardly ideal – the ‘shoulder seasons’ (Spring and Autumn) do provide significant benefits, and some households are finding the net cost of operation competitive with gas. When, finally, gas attracts the level of carbon tax it deserves, it will make it easy for ASHPs to compete on a level playing field in price terms.

Final Thoughts

I support the call for reduced consumption in all its forms, and it should be encouraged as much as possible, but this is not mutually exclusive with electrifying transport and heat. On the contrary, electrification helps in this endeavour, because of increased efficiency and flexibility. But it needs to be coupled with approaches that ensure  fair access and market reforms.

We need to acknowledge the issues hitherto in increasing the skills base for retrofit and renewable heat, and improving the quality of installs, but that is not a good argument for dismissing heat pumps. It’s an argument for a major push on the required training and quality systems, something the Government has lamentably failed to prioritise.

As CAT ZCB says, we need to ‘power down’ (stop wasting energy, use it more efficiently, and change some behaviours and norms), but then ‘power up’. The power up bit requires a lot electricity from renewable capacity, and a fair amount of storage too. They have a plan we can get behind.

Currently, the UK Government does not have a coherent plan across all sectors, but whatever plan we decide to finally put some real effort into, it needs to be one that stacks up.

And for those that claim that the CAT ZCB models and assumptions are optimistic, it is worth looking at others who are independently modelling the transition, and are optimistic about our ability to decarbonise the grid in relatively short timescales (see this commentary on a Colorado study).

As the sadly departed David Mackay said, he was not biased in favour of any one solution, but was in favour of maths. We all need to be fans of maths, and be clear about our assumptions, when conceiving and debating options.

Ultimately, electricity is a great democratiser of energy.  Generation is de-coupled from consumption in a way that was not (and never can be) true for fossil fuels used for cars or heating homes.

If you consume electricity in a light bulb, EV car, heat pump, fridge or lawn mower, you can take the renewable energy from any source – a wind turbine array in the North Sea, or a community energy scheme, or the solar PV on your house. All powered ultimately by the sun.

It is not surprising that those who have controlled the energy supply chains – from exploration and production to the petrol station forecourt or gas metre at your home – are putting up a fight to retain control, including greenwashing galore, and fake green gases, with the help of lobby groups and big marketing budgets, which is nothing to do with finding the right solution for consumers or the planet (as the dash for methane gets marketed as a dash for Hydrogen).

What is more surprising is that greens do not always appreciate the importance of electrification to both the decarbonisation and democratisation of energy.

It’s time they did.

(c ) Richard W. Erskine, 22nd July 2020


NOTE 1 – EV efficiency compared to Internal Combustion Engine (ICE)

EVs are about 90% efficient (so for every 1kWh of energy in its battery,  an EV will use 0.9 kWh to do work), whereas the Internal Combustion Engine (ICE) is typically around 30% efficient (so for every 1kWh of potential energy in the fuel, only 0.3kWh will do any work). That is a relative efficiency of 3 to 1 (in both cases excluding the energy losses between the engine and moving wheel).

Another way to calculate it is to take a figure of 60 mpg figure for a petrol car, and using a figure of about 30 kWh per gallon, that equates to approximately 2 miles per kWh of primary energy for a petrol car. Whereas, this source indicated 41 kWh battery capacity for a Cleo with a range of 250 miles, this is (250/40) approximately 6 miles per kWh. So, again, a relative efficiency of 3 to 1 in switching to a similar sized EV car.

NOTE 2 – Unravelling hydrogen hype 

David Mackay said in Sustainable Energy – without the hot air p. 129: 

Hydrogen is not a miraculous source of energy; it’s just an energy carrier, like a rechargeable battery. And it is a rather inefficient energy carrier, with a whole bunch of practical defects.


A hydrogen cell car is about 40% efficient in its end-use of energy, whereas an EV is 90% efficient. If it is ‘green hydrogen’ created from a wind turbine through electrolysis, the overall efficiency for the hydrogen cell car is roughly 50% * 40% = 20%. Whereas for the EV it is 90% efficient (in both cases ignoring relatively minor network losses – for gas or electricity – and in both cases excluding the energy losses between the engine and moving wheel).

20% versus 90% is not a great look for hydrogen cell cars, and would mean (9/2 =) 4.5 times as many wind turbines to support the same level of green mileage by UK drivers.


And if hydrogen is a poor choice for cars, then providing ‘low temperature’ heat for homes is a little crazy in my view. Whatever hydrogen we do produce needs to be reserved for high temperature industrial applications.

In Getting off gas: future risks for energy poor households (15th July 2020) Louise Sunderland wrote

But fossil gas is not the fuel of 2050. Hydrogen appears to be waiting in the wings to replace fossil gas in the grid. However, hydrogen is unlikely to be available in large quantities across Europe for home heating, as the available hydrogen goes first to those uses that rely on high temperature heat – which hydrogen can produce but electricity cannot. In the various 2030 and 2050 European decarbonisation scenarios, hydrogen for use in buildings is almost absent in 2030 and provides a small share of energy consumption in only some 2050 scenarios.

Importantly, projections show hydrogen will likely be significantly more expensive than a heat pump for home heating, and adapting to hydrogen will require upgrades of both the grid and home heating systems.

The availability and cost of hydrogen for domestic heat are at best uncertain. If low-income households are disproportionately reliant on gas, they will pay higher costs for infrastructure and be open to the uncertainty and price shocks of replacement fuels. 

Sourcing Hydrogen

An important question is: where would the energy come from to manufacture the hydrogen? Fossil fuel companies would love that we continue to source it from methane (currently 95% of hydrogen is produced this way), but a by-product is carbon dioxide, and then you have to believe it can be successfully buried using ‘carbon capture and storage’ (CCS). Yet CCS is unproven at the scale needed, and the timescales require urgent action. So the full supply chain for hydrogen today is far from green. And then there is the cost of storing this gas, and the infrastructure.

A study done for the Climate Change Committee in Analysis on abating direct emissions from ‘hard-to-decarbonise’ homes (Element Energy & UCL) , July 2020 looked at different scenarios. Interestingly it seems that for those scnearios involving hydrogen, the (probably prohibitive) costs of CCS and the storage off hydrogen are not included in their comparative cost analysis (because of their uncertainties). Whereas the oft stated hurdles for using widespread adoption of heat pumps such as developing the supply chain and raising the skills (relatively trivial things to fix) are highlighted ad nauseum.

But these hurdles could be addressed tomorrow, with an appropriate push from Government (e.g. legislating for air-source heat pumps for all new builds and post-build energy performance certification; and no gas connection). This would force the laggardly big boys in construction to institute the training required and pump-prime the supply chain. It ain’t rocket science. The UK Treasury need to end the short-sightedness that killed the zero carbon homes plan and the Government should tell the UK’s largest house builder to pull their fingers out!

Other ways of producing hydrogen exist, one of the most talked about is by electrolysis using excess energy from renewables, producing so called ‘green hydrogen’, but that these will never be greater than 100% (and electrolysis is around 50% efficient), so can never compensate for the lower of efficiency of hydrogen-cell cars when compared with EVs. 

And as Tom Baxter says in The Conversation, Hydrogen isn’t the key to Britain’s green recovery – here’s why

Much of my 45-year career in industry and academia has been spent studying energy efficiency and power production and supply. I believe that hydrogen has a limited role in decarbonisation, and that businesses with a vested interest in promoting hydrogen are doing so at the expense of British consumers.

Michael Liebreich has written on the economics of hydrogen in Separating Hype from Hydrogen, both on the Supply Side and Demand Side.

He has also published a Hydrogen ‘Use Case Ladder’ showing which applications of hydrogen make sense and which don’t. Cars and Heating are in the ‘don’t make sense’ section of the ladder (see NOTE 7).

Now, new research on the full life-cycle of ‘Blue Hydrogen’ shows it is anything but low carbon.

Hydrogen will play an important role in industry, and on the electricity power grid, providing a form of stored energy that addresses need to balance generation and demand over longer periods. Michael Liebrich shared a figure – the hydrogen use ladder – showing where hydrogen can/ should be used, and where it shouldn’t:


Whichever way you look at it, the hype around hydrogen around transport and heat is overblown.

Synth Gas

Nevertheless, there will need to be a role for synthetic gas – hydrogen or others – as an energy carrier and/or storage medium. 

The CAT ZCB report includes a significant role for synth methane for energy storage and backup. Their argument being that they can leverage existing gas infrastructure for backup power generation, for example, using truly green synth gas (so no CCS required).

Chemical storage is an important potential complement to gravitational (pumped storage, hydraulic storage) and battery storage, because it can be inter-seasonal in scope. But each must be judged according to its qualities (cost, carbon intensity, capacity, latency, storage, transmission, etc.).

Imagine arrays of solar PV in the Sahara generating electricity; how do you get that energy to where it is needed (Africa and Europe, say)? It could be via an electricity distribution network, but could also be by producing synthetic gas, and transporting that gas via pipelines. If the gas is easy to liquify (as Ammonia is), other options are possible. Instead of Liquified Natural Gas (LNG) from Qatar, we could have liquified renewable sunshine from Australia, which could become a leading post-coal energy exporter, with the help of Ammonia.


Ultimately, though, electricity is a great democratiser of energy, when freed from fossil fuels in its generation. Heat Pumps can get their electricity from any low carbon source and so, as David Mackay said, are future proofed.

NOTE 3 – Sustainable Energy without the hot air (2009), David Mackay

This book, available online, should be required reading for anyone who wants to discuss how to decarbonise a country’s energy supply and usage, not because it was the final answer on any scenario (nor claimed to be), but for its approach, which was to provide a tool kit for thinking about energy; to increase our energy literacy. The kiloWatthour (kWh) is a usefully sized unit of energy employed throughout the book, and also one that appears on our utility bills. A kWh per person per day (kWh/p/d) is a measure that makes it simple to assess our average consumption, and compare different options.

Mackay showed how energy consumption in UK would drop purely through electrification (assuming we still do more or less the same things), and since fossil fuels would be displaced by electricity generated without fossil fuels, we would eliminate most of the carbon emissions, but of course, the electricity generation would need to increase in the process (Mackay said that 18kWh/p/d should rise to 48kWh/p/d, or an increase by a factor of about 2.7, or an additional 170% electricity capacity) – See Figure 27.1 on p.204:

Mackay electrification

NOTE 4 – Centre for Alternative Technology’s scenario

 In Zero Carbon Britain: Rising to the challenge (2019), by the Centre for Alternative Technology (CAT) a breakdown is provided of the 2017 energy supply and consumption for UK as follows: 

ZCB UK energy 2017

Inefficiencies exist in the combustion of fossil fuels to produce useful ‘work’, but also in different end-use settings, such as electrical white goods (e.g. fridges) and lighting.

There are also reductions in demand possible by changing some of the things we do today, such as increasing the use of walking, cycling and public transport compared to car use, for example. Taking all those into account, CAT propose a 60% reduction in demand in their ZCB scenario: 

ZCB 60% reduction

How is demand reduced? For homes, it is a combination of retrofit and smart controls: 

ZCB home heat performance

For transport it is mainly through reductions in car use and electrification of transport 

ZCB transport 1

Leading to a very large reduction in transport energy demand …

ZCB transport 2

 NOTE 5 – Net efficiency illustration

In this quote from Mackay, he mentions a net efficiency of using gas to electrify heating, based on a Figure provided on page 150. I will do a simple calculation to illustrate a net performance figure. Mackay used a figure of 53% efficiency for gas powered electricity generator (top of line at the time of Mackay’s book) and an 8% transmission loss (92% transmissions efficiency); and an ASHP between COP of 3 – at the lower end of modern ASHPs – and 4.  The overall efficiency would be in the range between 0.53 * 0.92 * 3.0 = 1.46 and 0.53 * 0.92 * 4.0 = 1.95, that is, between 146% and 195% efficiency.  Mackay uses the range 140% to 185% in the quotation. The point being that any of these figures is much greater than the 90% efficiency from sending the gas to a boiler in the home to provide heating.

NOTE 6 – Heat Pumps are an old idea and not magic

By the mid 19th Century heat was understood as the jostling of atoms – the ‘kinetic theory of heat’ as pioneered by Maxwell and Boltzmann. The greater the temperature above absolute zero (0 Kelvin or -273.15 Centigrade) the greater the average velocity of molecules. A sea of water at 5oC contains a huge amount of thermal energy. We should be careful not to confuse the temperature of a body with its energy content! The energy content will be a function of the temperature and volume of the body of water (the same principle applies to a body of air). With a large enough volume, the temperature becomes relatively less important; there will still be plenty of energy to harvest.

The genesis of the heat pump dates back to the early-mid 19th Century, but the first water-sourced one was installed in Switzerland in 1912. Heat pumps are neither new nor extraordinary.

There is no magic. Heat pumps harvest the ambient heat (which can be in the air, ground or water) that ultimately derives its energy from the Sun. This is done through a process that is like a reverse fridge, but in this case moving heat from the outside (often at a relatively low temperature) to the inside (at a relatively higher temperature), with the help of a refrigerant medium and a pump and compressor. No magic is required, just a little A-level physics. 

Typically, if a heat pump uses one unit of electrical energy to drive the system it produces three units of heat. This equates to a 3/1 = 3 efficiency factor, or 300%. 

Roger Harrabin, is the BBC’s Energy and Environment Analyst. This is what he said in a report on a water-source heat pump installed to heat the historic house of Plas Newydd in Wales (science facepalm warning):

It’s barely believable that this sea water has enough heat to warm anything, it’s pretty chilly at this time of year, but yet, thanks to an extraordinary technology called a heat exchanger, it’s the sea that’s going to heat this house.

It is incredible but true that a BBC energy correspondent appears to not understand the distinction between the temperature of a body of water and its thermal energy content, and believes the technology is novel and new. This is not the only report he has made on heat pumps that demonstrates a complete misunderstanding of how they work. 

The gas network lobbyists championing allegedly sustainable gas in various forms must absolutely love Roger.

NOTE 7 – The Use Case Ladder for Hydrogen

… o o O o o …

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Filed under Renewables, Transition to Low Carbon

UK Covid-19 Testing Figures Untrustworthy

BBC’s More of Less is a real gem, shining a light on numbers bandied about in the news.

Today’s episode again discussed the UK Government’s Covid-19 testing claims.

It demonstrated to me quite clearly why we cannot trust the numbers being presented by the Government (Govt).

I have listened to the extremely informative 5.5 minute segment of More or Less (MoL) covering this topic – from just after 8’30” into the programme to about 14’ in – and taken some notes that I thought were worth sharing:

  • On Sunday 10th May Boris Johnson said

“we must have a world beating system for testing potential victims and for tracing their contacts, so that all told, we’re testing literally hundreds of thousands of people every day”

  • Matt Hancock has tweeted again on Monday 11th May, claiming “100,490 tests yesterday” (i.e. Sunday)
  • MoL have concluded that the Govt did not reach or surpass the 100,000 target.
  • Matt Hancock’s figure included 28,000 samples put in the post that day, but yet to be tested.
  • Actual tests conducted, that produce results, are “a long way” from reaching its target of 100,000 (let alone “ramping it up”), according to MoL.
  • Even by it’s own “somewhat questionable figures”, the Govt has only reached its target twice in May, and MoL don’t think they have ever reached it.
  • Govt has not acknowledged that a sample in the post is not equivalent to a test completed.
  • Sir David Norgrove, chair of the UK’s Statistics Authority, wrote to the Health Secretary asking that he shows more clearly how targets are being defined, measured and reported, to “support trustworthiness”.  Ouch!
  • The Govt won’t publish the actual number of completed tests (positive or negative) from postal samples. Instead they simply add the number of positive tests to the daily number of confirmed cases. Their ‘excuse’ being that they wanted to avoid double counting [my comment: as though this is not possible by other means in this day and age!].
  • MoL have no ideas on the actual number of postal tests being carried out, despite repeated attempts to find out.
  • It is not just the postal tests that are causing confusion.  
  • Since the middle of April, the Govt’s testing data have included tests from other organisations, such as Universities, and their’s are not just swab tests but antibody tests that can show who has had the virus in the past. They are doing this to look at the prevalence of the virus and to answer other research questions, such as how accurate the home testing kits are.
  • The Govt say that because the research tests are not for diagnostic purposes they are not included in the daily count of people who are tested. Yet, this week more than 17,500 of these tests are included in the number of tests completed!

“It’s almost as if they don’t care if the number of tests figure is consistent or indeed accurate, as long as it’s big” (Tim Harford, MoL Presenter)

  • This leads to another issue. The number of tests carried out is not the same as the number of people tested!
  • Now, of course, some individuals may be tested multiple times so we would expect the number of people tested to be lower than the number of tests [my comment: I would say clearly over a period of a week say, for medical staff, but for the general public? surely not].
  • But recall Boris Johnson talked of “hundreds of thousands of people every day”.
  • On May 10th, almost 70,000 tests were actually carried out (not including the number for those postal tests samples put in the post that day), but the number of people actually tested was 37,000 (as MoL gleaned from Department of Health (DoH) data).
  • This is roughly 2 tests per person each day.
  • MoL have asked the DoH for an explanation “but they haven’t got back to us” yet.
  • MoL are not sure what could be the issue, but wondered if there is an error in the collating and labelling of data. They will keep trying to get an explanation.
  • <End of Notes>

After listening to this MoL episode, I was discussing it with my ex-nurse wife who suggested “maybe they are using two swabs”. Duh, of course.

Is this the simple explanation we need? So, I tried to find out what happens at test centres.

The Govt YouTube video on the test centre process (viewed by only about 100,000 people) doesn’t mention 2 swabs; and implies just one.

Then I found Jack Slater’s piece in the METRO (Sunday 15th March 2020)

“One swab will be put in the back of your throat, and another will be placed inside both nostrils.”

So 2 tests are done for each 1 tested person, at least at some test centres; possibly all.

My cynical thought was then: is there some creative ambiguity going on in not distinguishing ‘tests’ from ‘people’. I tend to prefer the cock-up theory of history, but who knows?

Thank you More or Less for again offering a clear interrogation of the Government’s claims on testing.

I would conclude that the Government is in a complete shambles with respect to simply counting the number of actual tests carried out per day, and also, the number of people tested (whose sample or samples have been tested on said day); and clearly distinguishing these numbers.

Unless the Government can demonstrate clarity and accuracy in its presentation of the testing numbers, how can we trust it to implement a coherent strategy to achieve a “world beating system for testing potential victims and for tracing their contacts”?

Or even, how can it execute its basic job of protecting the public?

Currently, one has to conclude that the UK Government’s Covid-19 testing figures are untrustworthy.

(c) Richard W. Erskine


Filed under COVID-19

Following the science: what should that mean?

Following the science and politics

The ‘science’ represents the evidence, the ‘Is’, but we need values, the ‘Should’ to arrive at what’s possible, the ‘Can’, and then leadership, capabilties and capacity to turn that into action, the ‘Will’. Only when the plans are executed is it ‘Done’. The refinement loops come from ‘measure effectivity’ and ‘weigh opinion’, and there will always be a tension – sometimes a conflict – between these.


It has been a mantra repeated every day at the UK Government’s Covid-19 press briefing that they are following, or are guided by the science.

What does this mean or what should it mean?

Winston Churchill famously said that scientists should be on tap, but not on top. 

This meant, of course, that politicians should be the ones on top. 

Scientists can present the known facts, and even reasonable assessments of those aspects of a problem that are understood in principle or to some level, but for which there remain a range of uncertainties (due to incomplete data or immature science). As Donald Rumsfeld said, there are known knowns, unknown knowns and unknown unknowns. Science navigates these three domains.

Yet, it is the values and biases, from whatever colour of leadership is in charge, that will ultimately drive a political judgment, even while it may be cognisant of the evidence. The science will constrain the range of options available to an administration that respects the science, but this may be quite a wide range of options. 

For example, in the face of man-made global warming, a Government can opt for a high level of renewables, or for nuclear power, or for a radical de-growth circular economy; or something else. The science is agnostic to these political choices.

The buck really does stop with the politicians in charge to make those judgments; they are “on top”, after all.

So the repeated mantra that they are “following the science” is rather anti-Churchillian in its messaging.

If instead, Ministers said, “we have considered the scientific advice from the Chief Scientific Adviser, based on discussions of a broad range of scientific evidence and opinion represented on SAGE (Scientific Advisory Group for Emergencies), and supporting evidence, and have decided that the actions required at this stage are as follows …”, then that would be correct and honest. 

And even if they could not repeat such a wordy qualification at every press conference it would be like a proverbial Health Warning – available on Government websites – like on a cigarette packet, useful for anyone who feels brave enough to start smoking the daily propaganda on how brilliant the UK is in its response to Covid-19 (which, despite a lot of attacks on it, has not been as bad as some make out, and the Chief Scientific Adviser (CSA) and Chief Medical Officer (CMO) have rightly gained a lot of credibility during the crisis).

The uncomfortable truth is that ‘following the science’ is about proaction not reaction; about listening to a foretold risk years in advance and taking timely and substantive actions – through policies, legislation, projects, etc. – to mitigate against or build resilience in the face of known risks.

Pandemics of either a flu variety or novel virus kind have been at the top of the UK’s national risk assessment for a decade. Both SARS and MERS were warnings that South Korea took seriously to increase their preparedness. The UK was also warned by its scientists to be prepared. The UK Government under different PMs has failed to take the steps required.

Listening to the science in the midst of a pandemic is good, but doing so well in advance of one, and taking appropriate action is a whole lot better. Prevention is better than cure, is a well known and telling adage.

Of course, the naysayers will come out in force. If one responds to dodgy code prior to 2000 and nothing bad happens, they will say that the Y2K bug was a sham, an example of alarmism “gone mad”; they will not acknowledge the work done to prevent the worst outcomes. Similarly, if we mothball capacity for a pandemic, then once again, expect the charge of alarmism and “why so many empty beds?”.

Our economy is very efficient when things are going well – just-in-time manufacture, highly tuned supply chains, minimal redundancy, etc. – but not so great when shocks come, and we discover that the UK cannot make PPE (personal protective equipment) for our health and care workers and we rely on cheap off-shored manufacturing, and have failed to create sufficient stocks (as advised by scientists to do so).

Following the science is not something you do on a Monday. You do it all week, and then you act on it; and you do this for risks that are possibly years or decades in the future. You also have to be honest about the value-based choices you make in arriving at decisions and not to hide being the science.

Scientists don’t argue about the knowns: the second law of thermodynamics, or that an R value greater than 1 means exponential growth in the spread of a virus. But scientists will argue a great deal about the boundary between the known and unknown, or the barely known; it’s in their nature. Science is not monolithic. SAGE represents many sciences, not ‘the’ science.

For Covid-19 or any virus, “herd immunity” is only really relevant to the situation where a vaccine is developed and applied to the great majority of the population (typically greater than 85%), with a designed-in strong immunity response. Whereas immunity resulting from having been naturally infected is a far less certain outcome (particularly for Coronaviruses, where there is typically a weak immune response).

So, relying on uncontrolled infection as a basis for herd immunity would be naive at best. It is true that it was discussed by SAGE as a potential outcome, but not as the core strategy (as Laurence Freedman discussed here); the goal was always to flatten the curve, even if there was great debate about the best way to achieve this.

One of the problems with the failure to be open about that debate and the weighing of factors is that it leaves room for speculation as to motives, and social media has been awash with talk of a callous Government more interested in saving the economy than in saving lives. I am no fan of this Government or its PM, but I feel this episode demonstrates the lack of trust it has with the general public, a trust that Boris Johnson failed to earn, and is now paying the price in the lack of trust in his Government’s pronouncements.

Yet I do have confidence in the CSA and CMO. They are doing a really tough job, keeping the scientific advice ‘on tap’. They cannot be held responsible for the often cack-handed communications from Ministers, and failure to be straight about PPE supplies and the like.

Some people have criticised the make up of SAGE – for example, because it has too many modellers and no immunologists and no virologists. I don’t understand the lack of immunologists.

Virologists are clearly key for the medium-long term response, but a vaccine is probably over a year away before it could be deployed. So, at the moment, containment of the spread ‘is’ the Emergency, and social distancing, hand-washing, isolation, hospitals, testing, etc. are the tools at hand, and it might be defendable that they are not currently the focus of the discussion.

Groups at Oxford University and Imperial College are being funded to help develop vaccines and to run clinical trials. Virology is not being ignored and it is rather odd to suggest otherwise.  But again, transparency should be the order of the day – transparency on who is invited onto SAGE, when and why, and transparency on the evidence they receive or consider. But having a camera in there broadcasting live discussions may inhibit frank debate, so is probably not a great idea, but the Minutes do need to be published, so other experts can scrutinise the thought processes of the group.

The reason why Dominic Cummings (or any other political role) should not be sitting on SAGE, in my view – even if they make no contribution to the discussion – is that there is a risk (a certainty, probably) that he then provides a backdoor summary of the discussions to the Prime Minister, which may conflict with that provided by the CSA. It is the CSA’s job to summarise the conclusions of the discussion and debate at SAGE and provide clear advice, that the Government can then consider and act on. The political advisers and politicians will have plenty of opportunity to add their spin after receiving the scientific advice; not during its formation or communication.

Now, it seems, everyone agrees that testing and contact tracing will be key tools in ending or reducing the lock down, but of course, that means having the systems in place to implement such a strategy. We don’t yet have these.

The British Army, I understand, don’t use the term “lessons learned”, because it is so vacuous. We have “lessons learned” after every child abuse scandal and it doesn’t seem to make much of a difference. 

A lesson truly learned is one that does not need that label – it is a change to the systems, processes, etc., that ensures a systemic response. This results in consistently different outcomes. It is not a bolt on to the system but a change in the system.

Covid-19 asks lots of questions not just about our clinical preparedness but the fairness of our systems to safeguard the most vulnerable.

Like a new pandemic, the threats from global warming have also been foretold by scientists for decades now, and UK politicians claim to be listening to the science, but they are similarly not acting in a way that suggests they are actually hearing the science.

As with Covid-19, man-made global warming has certainties and uncertainties. It is certain that the more carbon dioxide we put into the atmosphere the warmer the world will get, and the greater the chance of weather extremes of all kinds. But, for example, exactly how much of Greenland will melt by 2100 is an on-going research question.

Do the uncertainties prevent us taking proactive action?

No, they shouldn’t, and a true political leader would take the steps to both reduce the likely size of impacts (mitigations), and increase the ability of society to withstand the unavoidable impacts (adaptation), to increase resilience.

The models are never perfect but they provide a crucial tool in risk management, to be able to pose ‘what if’ type questions and explore the range of likely outcomes (I have written In Praise of Computer Models before).

Following the science (or more correctly, the sciences) should be a full-time job for any Government, and a wise one would do well to listen hard well in advance of having to respond to an emergency, to engage and consult on its plans, and to build trust with its populace.

Boris Johnson and his Government need to demonstrate that it has a plan, and seeks support for what it aims to do, both in terms of prevention and reaction. It needs to do that not just for the Covid-19 crisis, but for the array of emerging crises that result from man-made global warming.

We need to change the system, before the worst impacts are felt.

(c) Richard W. Erskine, 2020.


FOOTNOTE – Sir Mark Walport and John Ziman – on science policy and advice

I listened to Sir Mark Walport a few years ago in a conversation about the role of Chief Scientific Adviser (a post he has held), which was very interesting


[This episode was recorded on July 21, 2016 in front of a live audience at Caspary Auditorium at The Rockefeller University.]

He said that any policy must look at a problem through 3 different lenses:
– Evidence lens
– Deliverability lens
– Values lens

and that science can only help with the first of these.

He made the point that trust in science is very context specific: Science can say anything about the Higgs Boson and be believed, but on an issue like embryology, values kick in and there will be much less trust.

He also makes a strong distinction between ‘pollable’ questions and non-pollable questions. I will give examples.

“does extra CO₂ in the atmosphere lead to increased global warming?” is a non-pollable questions (the unequivocal answer is: yes); whereas “should UK focus on renewables or nuclear power to decarbonise the grid?” is a pollable question (answer: Brits much prefer renewables, by a wide margin).

Scientists need a special range of skills to be able to do the advice job, above and beyond their scientific skills. John Ziman explored the differences between scientific discourse and political debate in his paper (2000) “Are debatable scienti􏰜fic questions debatable?”

Click to access Ziman.pdf

He explains how complex most scientific questions are, with rarely a simple resolution, and conducted in a way quite different to political debate (yet no less argumentative!). The two styles sit awkwardly together.

Yet public and political discourse (especially on social media, but in newsprint, and parliament too) often expects a binary answer: yes or no, right or wrong. Shades of grey are often not tolerated, and if you don’t ‘choose a side’, expect to get caught in the crossfire.

I haven’t read the belatedly released SAGE Minutes yet but I expect there will have been lots of discussions on points where Walport’s lenses (Evidence, Deliverability, Values) sit uncomfortably alongside each other.

At some point, I imagine a fly on the wall, hearing …

“we need to do test, trace and isolate as soon as possible”

“agreed, but we need to recognise the constraint that the test capacity is limited at the moment, so we’ll have to wait till we have flattened the curve enough, to reduce the testing demand, but also build up capacity; meanwhile we cannot avoid a lockdown”

“can someone answer this – how well will the public comply and how would this change the numbers?”

“we ran some sensitivity analysis, and we need very high compliance to make it work”


Leading to a messy compromise set of ‘options’ and scientists NOT the ones with the authority to choose which ones.

The scientists didn’t choose a context where Governments had failed to take on board prior recommendations over some years, to build capacity in PPE, etc. So the advice is very context dependent.

It is highly disingenuous of politicians to say they are ‘following the science’ when that is just one element in the decision making, and where a poor starting position (e.g. the lack of prior investment in pandemic responsiveness) is neither something they influenced, nor can change.

….  o o O o o ….

Updated with Diagram and Footnote on 28th June 2020


Filed under COVID-19, Global Warming Solutions, Transition to Low Carbon, Uncategorized

Becoming an artist: fundamentals


“you need three things for paintings: the hand, the eye, and the heart.  Two won’t do.  A good eye and heart is not enough; neither is a good hand and eye”

David Hockney reflecting on the Chinese attitude to art


I wrote about my ‘awakening’ in moving originally from a science background and finding my way to becoming an artist since my retirement.

Art may seem to be completely different to the science I grew up with, because there appear to be no rules. But the artist and scientist do have quite a lot in common, as I discussed previously:

        • a curiosity and playfulness in exploring the world around them; 
        • ability to acutely observe the world; 
        • a fascination with patterns;
        • not afraid of failure;
        • dedication to keep going; 
        • searching for truth; 
        • deep respect for the accumulated knowledge and tools of their ‘art’; 
        • ability to experiment with new methods or innovative ways of using old methods.

The difference is that in science we ask specific questions, which can be articulated as a hypotheses that challenge the boundaries of our knowledge. Whereas in art, the question is often simply ‘How do I see, how do I frame what I see, and how do I make sense of it?’ , then, ‘How do I express this in a way that is interesting and compelling?’.

In art we do not have rules like in science, but in order to make progress, it is important to articulate guidelines, or fundamental principles if you like.

My starting point is a desire to create representational art, but including impressionistic styles, and even abstractions. I am not interested in trying to create a perfect copy of a scene, because as I often say, if that was my objective I would use a camera, not a paint brush.

This is not about being lazy and not wanting to create all that perfect detail, but rather to highlight the fact that a painting is doing a completely different job to a photograph; it is an expression not a record.

This is the second essay in a series I am writing on Becoming an artist, and I want to turn to the fundamentals.

The fundamental principles can be loosely grouped under the following headings:

  • Heart – learning to develop one’s creative impulse;
  • Eye – learning to observe as an artist does;
  • Hand – learning general techniques applicable to any medium.

I cover just those principles that I have internalised particularly over the last few years as a student of Alison Vickery, my mentor on this journey.

I haven’t read Hockney’s reflections on the Chinese artist tradition, but it is curious that I independently – in my first draft of this essay – came up with Practice, Observation and Technique. It was Alison who suggested it fitted well with the Chinese approach that Hockney espouses, so I changed the headings to Heart, Eye and Hand. Maybe these really are universals that any student of painting, from any culture, will recognise on reflection.

I am always questioning things “why do you do that?” or “how do you do that?”, and then trying to find the why behind the why. 

Alison has never written down this list, this is my appreciation of the lessons I have learned, and I am sure I will have missed some important elements out, or presented things differently to how a professional artist like her would articulate things. 

I am sharing my journey and the ideas that have helped me, and so feel free to use and abuse these ideas in your journey.


The emotional side of painting is in many ways the most important. When you feel free to express yourself in the way you want, you are, by definition, an artist. 

While you try to be someone else and to follows somebody else’s standards of what you think you should be and do, then you will struggle to find your voice, and your language for expression. 

Under the heading of ‘Heart’ I highlight the things that most influenced me in finding my voice, which includes aspects of expressiveness.

Loosen up

In sport you need to do a warm up, and in art it is also important to free up any tension in your mind or body.  Try to start a session on a cheap piece of paper first (so you won’t stress about ‘wasting’ an expensive piece of art paper).

Even when doing a piece of work you wish to develop, you still need to be bold and work fast, initially at least, and avoiding tightening up.

Start with the biggest brush you can get away with, hold it loose not tightly.  When you start painting, avoid fine brushes altogether; they will kill your ability to work loose.

For watercolour, try starting with a size 12 brush  – a decent quality one that will hold a lot of pigment but still make a point.

Loosen up. Make mistakes, they may be happy ones.

Work the whole area

The opposite extreme would be to start painting in the bottom left and work your way up to the top right, or for Michelangelo to carve out the perfect head of the David before moving on to doing his willy! No, as with a sculptor, you must ‘chip away’ all over the subject in broad bold strokes.

As you move to less bold and more detailed strokes, still keep working all areas of the ‘canvas’.

A huge benefit of this approach is that you will being to see things that influence how you develop the painting. Maybe you had a preconception of how you wanted to develop it, but you can now see how to make it better.

Don’t be afraid of white space

Working every areas of the paper is not the same as covering every area with paint – it is ok and actually desirable to leave areas of white space (or whatever the background colour might be). You need the light to get in.

White might be used to suggest light falling on a subject; a painted tree might be dark on one side where there is shadow, and white on the other, suggesting light from the sun.

This is particularly important with a medium like watercolour, where you need to compensate for an inherent difficulty in creating good contrast, and the white space can help to achieve it.

Use sketches and studies

As part of trying to get to know the scene better, do several quick sketches or studies, maybe starting with a charcoal drawing, then a very quick watercolour. Give yourself a short time just to produce something. Use cheap paper again.

Perhaps tear off bits of paper and see how it changes your perspective on things.

Mess around. Don’t self censor. Just go for it. 

If you create something that you think ‘that looks interesting’, then cut it out and paste it into an art journal, and add some written side notes “I wetted the paper and dropped in a swathe of cobalt blue, then dabbed it with kitchen towel to create a cloud”. Build up an inventory of such experiments.

Play with composition

After doing an initial sketch of a scene, you can use a ‘window’ cut out of card (with the required aspect ratio for the final painting), placed at different distances from the sketch, and use it to see how much you want to include in the final piece.

Maybe you decide that the house in the foreground is a distraction from the copse on the hillside which is what you really want to be the main focus in the composition.

Learn when to stop

Picasso once said that a finished painting is a dead painting.

It is so easy to over-work a painting, so learning where that inflexion point occurs – between improving a piece and killing it – is perhaps the most difficult skill of all.

Always err on being slightly underdone to overdone.


Painting is not photography. You are not trying to replicate what a camera would see. 

You are creating an impression that speaks to you (and you hope, will speak to others, but that is a bonus). While the work is representational, that does not mean you cannot be impressionistic.

You can decide to remove the annoying road sign that is upsetting the composition; make the clouds more moody; or whatever you care to. But it is important to learn to observe. Having a good eye is as important as having a good brush!

Paint what catches your eye or interests you

It might be the shape of a tree that intrigues you, or the curve of a river, or the curious shape of a cloud, or the tree line on a brow of a hill. Whatever it is, it is a great subject for you, because you are emotionally invested in it.

Learn to be acutely observant

How much time are you spending looking at the paper, and your brush strokes and how much time observing the subject matter? As a novice it is often a 80/20 split in time, when if anything it should be a 20/80 split.

The more you look, the more you see. The brain is telling you that the grass is green, but look closely and in the evening sunlight there seems to be some blue grass in the shadows of the tree – impossible? No, trust what you see.

The light from the window makes the shoulder of the sitter look almost white, but how can that be – they are wearing a black jacket. Look again, trust what you see.

Even if you don’t particularly like drawing, it is worth having a go, because it is another way to help develop one’s observational skills.

Think tonally

It is so easy to become obsessed with finding the right colour to use, but much more important than colour is tone.

Seeing the dark patches lurking in the depth of the wood, and noting that even on the apparently uniformly yellow daffodil there are shades and shadows, that help create a sense of volume; these are example of being tonally observant.

Having a good tonal range can really bring a painting to life.

Doing charcoal studies can really help to develop a sense of tone, unencumbered by considerations of colour.

When preparing to compose a picture, establishing the tonal range of the scene or subject is one of the most important things you can do.

Hard and soft edges

Often we feel compelled to paint or draw a hard edge because our brain says ‘there is a vase there, so I will draw around it’. Look more carefully and the brightly lit side of the vase blends in with the brightly lit background, creating a soft barely discernible edge. Resist drawing what you cannot see!

Look through someone else’s eyes

Take time out to step back, get a sup of tea, and then imagine you are someone else viewing the painting for the first time.

Does it grab you? Have you resolved the different elements of the composition? Have you established a focal point that draws the viewer in?

Look out for symmetry

Humans seem to like patterns in nature and one of the most universal patterns is simple bilateral symmetry – the kind created by the reflection of a scene in a body of water (with a horizontal line of symmetry), or created by the centre line of a tree  (with a vertical line of symmetry).

It can really help draw in the viewer to exploit the symmetries we see around us, in our paintings.


A background may naturally present itself, as in a landscape, but in a studio, doing a still life for example, there may be a white wall behind the subject and little else. To avoid a painting looking flat, it is helpful to create a background, even where none exists. Maybe some imagined shadows or some texture on a wall will help.

Think about how a background might enhance the composition. It is so easy to get lost in a subject in a foreground, and forget how important a background can be in developing a composition.


Most, but not all, of the techniques described below are applicable to any of the painting mediums I have in mind: charcoal, pastel, watercolour, ink and acrylic. 

Later essays will focus on techniques specific to each medium. There are hundred of different techniques and ‘tricks of the trade’ out there. You will never stop learning new ones, but it is easy to get overwhelmed. I have included here the ones I feel are most important, at least to me.

Experiment with mark making

Try using different shaped brush heads, and other tools to create marks on a page.

We cannot all be Van Gogh who created his own brilliant style of mark making, but we can all just have a play.

To illustrate this, think about how you might paint a branch of a tree. You could use a classical pointed watercolour brush and carefully follow a line to mark out the branch. But you might struggle to control the thickness of the branch.

Alternatively, you could use a very wide headed flat brush to create the branch with a single dab of the brush.

Use brushes of different shapes and sizes, twigs, bunched up cloth, sponges, palette knives, or whatever; depending on the medium.

There are no rules with mark making – only that you approach it with confidence – so best to just try out as many variations as you can. Find out what works for you.

Play with negative spaces

A brightly lit vase on a table with a dark background might be approached first by painting the dark background – the vase will appear out of the darkness.

This idea can we be used in different ways, even when doing a simple sketch. Wainwright’s pencil drawings of the Cumbrian hills often include sheep, brightly lit from above. So instead of outlining the back of a sheep, he drew the grassland in the background; a sheep then appears as the negative of the grassland.

Use layering / glazes

When a medium is translucent or thinly enough applied to effectively be so, one can build up multiple layers to create a desired effect. 

In some cases – particularly with pastels – the painting may need to be fixed before proceeding further to avoid muddying the colours.

Surprisingly, even when using a medium as basic as charcoal, it is good to think in terms of layering.

With watercolour, glazes can help to develop depth.

Just as an old piece of furniture develops a patina, a painting can also develop a sense of complexity from multiple glazes.

Thin and thick

In any medium, it is normally best to start thin and only later to use a thicker form of the medium.

In acrylics, this is very important (in oils also, but I won’t be discussing oils in this series); using a more diluted medium at first. But the same applies to watercolours where one starts with light washes on the wet side, and only later might use some gouache on the drier side for some highlights.

The idea applies to pastel painting also. You should use light strokes with the side of a pastel stick at first.

Minimal palette 

Try when working in colour to use a minimal palette. Primary colours and white at a minimum.

It is a great discipline to learn how to make one’s own greens, browns and greys. With 2 yellows and 2 or 3 blues you can make a huge range of greens, for example.  As with all rules, you may want sometimes to break this rule; a ‘sap green’ can be difficult to replicate and is useful for bright foliage.

By using a small palette it makes it easier to tie the painting together, chromatically.

One can always add a few additional hues to finish a painting.

Knocking back

Sometimes a pigment is too bright for the current situation, such as on a grey day in winter. By adding a little of the complementary colour (on the opposite side of a colour wheel), it dulls the intensity of the pigment you are going to use.

With watercolour you can also, of course, reduce the hue intensity by adding white gouache.

Use of resist mediums

A ‘resist’ medium is something you can place on the paper (or canvas, or board) that will not absorb the pigment being applied to the surface. This can be for a range of reasons.

A masking fluid can be used to precisely cover a shape that must remain white in the final piece, or at least, not be covered by whatever is about to be painted over the medium. The fluid must dry fully then be removed by rolling a finger over it. This is ideal, for example, for snowdrop flowers.

The other kinds of resist medium tend to be ones that are used to cover a line or area and remain in place. For example, wax or a clear oil pastel crayon. These can be used to create texture – when wanting to create some extra effects in clouds, or in some landscape or on a building. 

Alternatively, resist might be used to suggest gaps between trees or foreground grasses, or some other effect where you don’t want the background (usually white, but not necessarily so) painted over.

Wet and dry

Particularly with watercolour but also with acrylics, the amount of water used when applying pigment can have a big impact on the picture. There is frequently a benefit to starting quite wet and allowing pigment to flow a bit. This avoids getting hard edges too early in a painting’s development. You can also just drop in other pigments and just see what happens.

You may need to use a hairdryer at some point to allow you to move onto a new wash or glaze / layer.

Later on, it may be you need to do some relatively dry work, dragging a relatively dry and lightly loaded brush – without completely covered the area – in order to deliberately generate striations. In a watercolour, this might be done with water colour pigment added to white gouache, for example.

Dabbing, rubbing and scraping

Sometimes, it is useful to be able to partially remove medium in order to create a necessary effect.

When doing a charcoal sketch, the rubber is as important as the charcoal in building up a patina to develop the image.

In watercolour, a paper towel can be all one needs to instantly create a cloud in a sea of blue that has just be painted.

For acrylic, scraping an upper layer of pigment away – before it has completely dried – to reveal pigment below can be used in number ways, such as helping to suggest a line of trees on the ridge of a hill.

Flicking and spraying

No one wants to paint every leaf on a tree and there is no need to. Look at a tree painted by Turner or Constable and you will see a fair number of brush strokes for foreground trees, to give the impression of detail, without excessive labour, but only broad strokes for distant trees.

Modern painters will often use an additional technique of flicking or spraying pigment to suggest the necessary complexity of the foliage. It can be repeated for different hues to create additional complexity.

Flicking of white gouache, slightly diluted can be used to help suggest the froth of a breaking wave, for example.

It is useful to have a cheap brush with quite stiff bristles (such as one might use for applying PVA in collage; if not available, an old toothbrush will also do the trick), as this allows one to do flicking by merely stroking the bristles (rather than using the wrist), giving much greater control.

Consider the interplay of simplicity and complexity

As we have seen with use of layering, resist and flicking techniques, there are several ways in which to develop complexity, and the human eye is intrigued by complexity. 

That is why we prefer to look at a rusty corrugated tin roof to one that is pristine and uniform. Yet we also like simplicity. A perfectly  rendered blue sky, a flat sea and a wide sandy beach – with just a small sailing boat in the distance – brings a sense of calm.

In developing an idea for a painting we can observe this interplay of complexity and simplicity in the world around us, and then decide how we might render it.

Consider the interplay between precision and imprecision

The painter must choose where to put effort into developing detail.

Typically, the subject is given more attention and other elements of the composition are allowed to be imprecise. A photographer, when doing a portrait amongst a landscape, will often use depth of field to make the background loose focus, and in a way so is the painter, but with greater freedom to emphasise or play with this imprecision. 

It may be that one needs the woodland on the distant hill to frame the picture of the family by the river, but the trick is to be very imprecise in how it is rendered – less is often very much more.

Choice of paper or other surface

There is a bewildering array of different surfaces to paint on. 

Papers can come in different weights and also levels of roughness of the surface.

Pastels require some grain on the surface to ‘take’ the pastel. Watercolour paper can be smooth or mottled and it depends a great deal on how wet you want to work, and whether you find the texture a help or a hinderance.

You will learn about stretching paper, and about priming paper or board with gesso. 

For any single sheet of paper, you need a board and masking tape to secure it to the board. Whether you need an easel or not depends on how you end up working. Some artists work so ‘wet’ they need to use a flat surface to work on with the ability to raise one side to cause the medium to flow; this is a long way from the classic image of an old master with the canvas on an easel.

Ensure you have some cheap cartridge paper you can experiment with, so you don’t get frozen by the thought that ‘this board is so expensive I better make this one a masterpiece!’. 

It can also help to have a range of sizes, so try doing small watercolour pieces, before migrating to larger formats. It is quicker to get a result and also takes the pressure off you.

Whereas for charcoal, you generally need to work on a bigger piece of paper straight away; but a relatively low cost large format ring-bound sketch book (around A3 size) is fine for this purpose.

Mixed media

In truth, many painting use mixed media, although some more obviously than others.

For example, a watercolour may use a number of other media:

    • pens to resolve some features (but best used sparingly), such as railings;
    • inks to help develop greater tonal depth;
    • gouache to finish a piece with greater colour intensity, for flicking effects or for white highlights;
    • pastels to help develop a light glaze of texture – for foliage or other features – as a finish.

There are also numerous special materials that can be tried, such as liquid pencil, to create effects.

But there is no obligation to throw everything at a painting, and it can be easy to get carried away with mixing media.

A great artist like Kurt Jackson has developed his own brilliant style – a vocabulary that is special to him – and his use of mixed media feels unforced and natural.

It is always best to start simple and work on adding ingredients over time, as and when they come naturally to you, rather than merely including them to try to emulate Kurt.


These fundamentals are the things I have internalised from an intensive three years of learning to become an artist, with the help principally of my mentor Alison Vickery, but also some other helpers along the way.

In the following essays, I want to show how these fundamental are reflected in sketches, studies and a few developed pieces I will share, from my endeavours.

I often forget these principles, catching myself in an act of regression, and then have to remind myself. Alison’s voice is often in my head …

‘paint what interests you’

‘don’t get too fiddly’

‘work the whole area’

‘stop right there!’

‘put down the pencil’

‘is the tonal range ok?’

‘loosen up’

I call them “Alison’s Aphorisms”.

It takes years to internalise the fundamentals of being an artist, and even then, so easy to get carried away and still fall flat on one’s face.

Equally, as time goes by nice surprises happen. 

You find that you ‘accidentally’ created something quite good, and you scratch your head and ask ‘How did I manage that?’. 

Don’t be surprised, you are becoming an artist!

Gradually, the better stuff happens more frequently and the not so great become less frequent. The art folder gets fatter and the dustbin less full of discarded pieces.

But everything you do provides a learning moment. Keep some of the not so great paintings to remind yourself of how far you have travelled.

Keep asking questions; it worked for me when I was a scientist and as a consultant, and it is something I continue to do as an artist.

Keep experimenting, and keep asking questions.

Making mistakes is fine, because that is the only way to learn.


(c) Richard W. Erskine, 2020

Next essay in this series will be Becoming an artist: sketchbooks

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Becoming an artist: awakenings

This is about my journey. Everyone’s journey will be different. I am addressing those, who like me, have spent a long time thinking about doing art, but never finding the time or courage to do it.

How many people suffer from that debilitating idea “I can’t paint*”. This is often because someone told you so, or gave your confidence such a knock, you never quite recovered enough to try again [* paint, or anything else you would like to do – learn to play an instrument, be a sculptor, do maths, play the drums, or whatever].

Schoolchildren are expected to make a choice quite early in life as to what they want to be. At face value it seems reasonable to expect a student to start to specialise at some point, but the mirror image of this is that they must ‘drop’ a whole load of stuff that is valuable in life. Little wonder that in older age people often pick up on subjects they loved but did not have an opportunity to develop when young.

I chose to specialise in science, even before I was forced to make that choice. 

I’d happily freeze to death looking at the moon and stars through a small but much loved telescope, clutching my Observer’s Book of Astronomy (I think I may have had a 1st edition from 1962, when I was just 9). Geometry was my favourite subject. 

A little later but still quite young I had a laboratory, and loved to do experiments with bits of apparatus such as a Liebig Condensor, regularly causing a stink that required all the windows in the house to be opened to clear the smell.

I was never a rote learner. I always asked questions and challenged my teachers. I love the ability of small children to ask “why?” then why again, to never be afraid to ask questions. But it is also important to learn how to listen to the answers, to reflect on them and then to do work to explore things more deeply. This gives rise to more questions.

I wanted to understand the world and how it was put together, and went on to study Chemistry at university. To highlight my tendency to question things, there is a story from my final exams I want to share. 

There was a question about chemical bonding I didn’t like because of the way it was framed, so I answered it just like I knew the examiner would want it answered, but then wrote “However, I want to challenge the framing of this question, and believe the question ought to have been …”. 

I then wrote a second answer to my newly framed version of the question. The external examiner (Prof. S F A Kettle, I believe) was so impressed he told my mentor that he would have happily awarded me an upper first if such a thing existed. Nevertheless, I was very proud of the 1st Class Honours degree I did receive.

I stayed in academia for a while, doing a PhD at Cambridge and then a postdoc in Bristol, where I met Marilyn, who was to become my wife. 

For a range of reasons, I decided to leave academia in 1982, and worked in computer-aided design for several years, but for the final 30 years of my career up to 2016 I was an information management consultant, helping large organisation to be better at breaking down the information silos in their organisations, and be better custodians of their knowledge.

I enjoyed using creative ways to discuss and articulate problems. I never stopped asking questions. Clients liked my thoughtful approach, and the fact I didn’t try to ram software products down their throats (as had been their experience on the previous times somebody had promised to fix their issues).  In ways that I now recognise only in retrospect, my scientific and artistic sides both found expression in the way I did consultancy.

Throughout this time, I was always questioning myself, always learning from new engagements about other ways to look at things. Even when one thinks one has mastered a skill, there will always be opportunities to explore nuances or discover new variants of a skill.

Over my 63 years before I retired I had tried on a few occasions to learn to paint. Even at school there was a group of us scientists who showed artistic promise and the art teacher allowed us access to the studio to paint just for fun, not for any examination. And I have attended classes on watercolours 30 years ago, but it never went anywhere.

Meanwhile, one of the favourite activities that Marilyn and I enjoyed over these years was visiting art exhibitions, and we have numerous catalogues to testify to this. I was great at looking at art, but not doing it.

There could have been many reasons for the failure of my early attempts to develop further. 

I had a time-consuming and at times stressful job, involving a lot of travel abroad. Marilyn and I brought up two girls, and there were always too many projects (that, funnily enough, seems not to have changed!). In Bristol I was an early recruit to Scientists Against Nuclear Arms (SANA), and became its Secretary for a while. Writing and speaking took up a lot of my extra curricula head space (SANA later became SGR, Scientists for Global Responsibility, and is still active).

Since my retirement, I have become very active on climate change, giving talks and helping to found a group, Nailsworth Climate Action Network in my home town, which I am currently Secretary of.

Despite being busy with family – now with grandchildren – and home, garden, climate change, etc. I decided I wanted to have another go at learning to paint. 

Marilyn and I have for several years tried to stop buying stuff – we have too much already – and instead buy vouchers for experiences or classes. 

About 6 years ago she bought me a voucher for a set of 1-to-1 art lessons from our dear friend Di Aungier-Rose. Unlike previous art teachers I had tried, Di was very good at getting me to loosen up and not stress about what I was doing; to not obsess about colour and so on. To just have fun, and see what emerged. She imparted little nuggets of wisdom here and there, but without overloading me.  

This unlocked the first door to me becoming an artist, and gave me a boost in confidence. I knew from that point on that I had an innate ability to become an artist, even while I knew it would be a long journey.

However, the ‘3 steps forward, 2 steps back’ rule seemed to hit me. I got waylaid by climate change, sorting out my pension for retirement, etc. There is always a long list of things stopping us doing what we want!

Also, I was really hankering after learning how to use watercolours, and had a lot of admiration for the work of another local artist, Alison Vickery. So, a few years ago Marilyn bought me another present: to attend a batch of classes at Alison’s weekly art class, held at Pegasus Art in Stroud.

I will talk more about what Alison has taught me in later essays in this series, but the key point here was that I started to carve out a time during the week – every week – when I wouldn’t be distracted by the other things crowding in on me. Wednesday afternoon was to be art time. So even if I didn’t manage to do any art during the rest of the week, this time was sacrosanct.

I have kept attending these classes ever since.

Maybe that is the secret – and of course a lot easier when you are retired – to find a space to do your art. 

If you are very disciplined and no longer require a mentor, then it is perfectly possible to create this time and space for yourself. It may mean creating a Woman Shed or Man Shed in the garden, to get away from domestic distractions.

However it is done, you need to find your time, and your space.

You need to unlearn the “I can’t do X” gremlin in your brain.

Now it is time to loosen up; to experiment; to ask questions; and to rediscover the joy of learning something new.

(c) Richard W. Erskine, 2020

Next essay in this series will be Becoming an artist: fundamentals

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Keep Calm, But Take Action

How do people respond to ‘signals’ regarding their health and well-being? 

Some people will refuse to respond, such as these smokers I saw outside a hospital a few days ago (where I was visiting my daughter, thankfully now discharged after a nasty infection; not coronavirus).

Screenshot 2020-03-13 at 07.27.24

There is a large sign ‘Strictly No Smoking’, that is routinely ignored.

And what of people who read Richard Littlejohn and others, for years in the Daily Mail, Daily Telegraph, The Spectator, etc., railing against the ‘nanny state’ or ‘elf and safety’ ?

Large swathes of people are effectively inoculated against alarm, and will not respond to signals, even if a megaphone was put to their ear. 

These are the super-spreaders of denial and complacency. 

I am not talking here of professional dissemblers in the climate realm who make their living trying to undermine the scientific consensus. Those who write opinion pieces claiming, wrongly:

  • more CO2 is good for us because plants will flourish (Matt Ridley);
  • or claiming ocean acidification is non-existent (James Delingpole);
  • or that it’s the sun’s fault (Piers Corbyn);
  • or that we are about to enter an ice age (Daily Mail and Daily Telegraph every 6 months for the last 10 years) .

Like stories of Lord Lucan sightings, these lazy opinion formers simply dust off the old rubbish to serve it up again, and again. Year in year out. It pays the mortgage I suppose. And when they tell people what they want to hear – that we can carry on regardless – there is no shortage of chortling readers. Ha ha ha. How very funny, poking fun at the experts.

No, I am  not talking about these dissemblers, but rather, the mass of those who have been reading this rubbish for 30 years and are now impervious to evidence and scornful of experts.

And there is an epidemic of such people, who believe

no need to be alarmed, staying calm and carrying on regardless 

It is not just health or climate change, but is applied universally. For example, the  Millennium Bug was apparently overblown according to these people (having seen the code that needed fixing, I can assure you, it wasn’t).

However, those who deal with addressing threats are in a no-win situation: if they act and prevent the worst happening, then people – who are largely unaware of what is being done behind the scenes – will say ‘you see, it wasn’t a problem’.  If they didn’t act, then guess who would get the blame.

Yet when people do raise the alarm, such as when parents wrote letters complaining of the risks of the vast colliery tip adjacent to the Welsh town of Aberfan, they are often brushed off, and the result was a disaster that lives on in our memory (see Note).

Now we have the Covid-19 virus. 

It is no surprise that there have been many saying that people are being unnecessarily alarmed; and the message is the same – we should ‘Keep Calm and Carry On’.

It’s just like seasonal flu, don’t worry. It will disappear soon enough.

These are often the same people who rail against ‘climate alarmism’.

Man-made global heating will be orders of magnitude worse than Covid-19, across every aspect of society – food security, sea-level rise, eco-system collapse, mass migration, heat stress, etc. – and over a longer timescale but with increasing frequency of episodic shocks, of increasing intensity.

Unlike Covid-19, there will be no herd immunity to climate change.

But we have the ability to halt its worst impacts, if we act with urgency.

We cannot quarantine the super-spreaders of denial and complacency, but we can confront them and reject their message.

I wonder, as the mood seems to be changing, and experts are now back in fashion it seems, could this be a turning point for action on climate change?

Can we all now listen to the experts on climate change?

Can we Keep Calm, but Take Action?

(c) Richard W. Erskine, 2020



There was a collapse of part of the massive colliery spoil tip at 0915 on 21st October 1966  The main building hit was Pantglas Junior School, where lessons had just begun. Five teachers and 109 children were killed in the school.

As one example of numerous correspondence prior to this, raising concerns, was a petition from parents of children at The Grove school raising the issue of flooding undermining the tip. This was passed up through the bureaucracy, but a combination of the Borough Council and National Coal Board failed to act. As the official report noted in unusually strong words:

“As we shall hereafter see to make clear, our strong and unanimous view is that the Aberfan disaster could and should have been prevented. … the Report which follows tells not of wickedness but of ignorance, ineptitude and a failure in communications. Ignorance on the part of those charged at all levels with the siting, control and daily management of tips; bungling ineptitude on the part of those who had the duty of supervising and directing them; and failure on the part of those having knowledge of the factors which affect tip safety to communicate that knowledge and to see that it was applied” (bullet 18., page 13)

1966-67 (553) Report of the tribunal appointed to inquire into the disaster at Aberfan on October 21st, 1966

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Thoughts on starting a community climate action group (a talk)

Good evening.

Professor Katharine Hayhoe, a leading climate scientist, and hugely influential communicator, is often asked:

What is the first thing I should do about climate change?

Her answer is simple:

Talk about it!

How on Earth can that reduce our carbon footprint you may ask?

On the other hand, it is a common phenomenon when climate groups start, that the first thought is often ‘we need to build a solar PV array on the edge of town’. 

I am not saying don’t do that, but there are big benefits to talking about it, and not rushing to build.

  • Firstly, if people are not fully on board with the idea that urgent action is needed to address global warming, then some talking will really help change hearts and minds.
  • Secondly, there are many different ways we can reduce our carbon footprint, and we need to push forward on all fronts. Don’t let the enthusiasm for one project crowd out ideas for other things that need to be discussed, and weighed up.
  • Thirdly, if we focus solely on technological solutions like electric cars, we potentially exclude a lot of people who are put off by technology, or cannot afford to invest in them; and would like a reliable bus service to be a priority! 
      • We need to build a much bigger tent where we discuss topics like consumption, waste, heating, public transport, energy efficiency and local food. Topics that will draw in as wide a population as possible.
  • Finally, by developing a wide perspective on all different approaches and potential initiatives, the group will be in a better position to call on community support for emerging projects.

Some will argue: but why is the challenge of addressing dangerous global warming being placed on the shoulders of householders and local communities? 

Surely, Government and big business have the resources and power to make it happen?

I reject the implied binary thinking here.

In fact, Government, big business, pension funds, County Councils, District Councils, Parish Councils, local businesses, householders – you and me – can all make a difference and influence what happens.

Ok, so there are some things that only Governments and big business can do. But ultimately, every product and service is – directly or indirectly – created for us. 

We have agency – we can decide: 

  • what we do, 
  • how we do it.
  • and how often we do it.

We can choose to car share twice a week; or opt for that staycation; or reduce our meat consumption. Every family is different, but we make lots of choices, intentionally or not; and every choice matters.

We started NailsworthCAN in 2016 around the time of the Paris Agreement. Our focus was always on practical action rather than protest. But action comes in many forms: engaging, influencing, networking, capacity building, constructing.

We have spent a lot of time developing the conversation with different groups in the community: with the Town Council, Church, Schools, Rotary, Transition Stroud, etc., and with our previous and current MP.  We act sometimes to lead, sometime to act as a catalyst, and sometimes simply to provide support to others. Hence the use of the word ‘network’.

We have run stalls, organised talks on diverse topics, and identified a range of projects. We created and distributed a Carbon Pledges sheet. We have met and talked with hundreds of local people, and we have recruited members with a fantastic range of skills and knowledge.

We have ran workshops to gather ideas on local projects that people are interested in across a range of topics –

  • Food and agriculture;
  • Mobility and transport;
  • Buildings and their environment;
  • Energy generation;
  • Waste;
  • Nature and the Environment;
  • Health and Wellbeing.

We have worked with the Town Council to help develop an outline plan across these areas.

One specific initiative is to conduct a survey of hospitality venues in town to assess current practice on energy use, waste, etc., and identify ‘wins’ for these venues, the town and the planet.

Another initiative is to develop a 5-year tree planting plan on council land.

And another is a community-led domestic retrofit scheme.

And yes, we have a few renewable energy generation schemes in the pipeline.

Each of the climate groups I have met has its own personality, way of organising, and methods for coordinating their efforts with their respective Parish councils.

Each has had ideas on how to push forward on different fronts, and all can learn from each other.

The great evolutionary biologist E. O. Wilson – when being interviewed on BBC Radio 4’s ‘The Life Scientific’ said:

“Humanity has Palaeolithic emotions, medieval institutions and god-like power, … and that is a dangerous combination”.

But I would respond by saying we also have the capacity to overcome our destructive power, and work collectively to reveal the positive side of our humanity.

Don’t be critical if you start with talking, then move to small actions.

Just don’t stop at small actions.

Small actions can provide learnings and help us move to larger ones.

Share and celebrate success, as we do on social and printed media. 

Small conversations can be the foundation for bigger ones, resulting in significant actions, and system change.  Ultimately, this is all about system change; business as usual  will not get us to where we need to be.

Remember, it is a marathon not a sprint, and like a marathon, we need to help each other stay the course.

I wish Minchinhampton every success as it starts its conversation.

Thank you.

…. o o O o o ….

Richard W. Erskine, Secretary of NailsworthCAN

Invited talk at the launch of Minchinhampton Climate Action Network.

11th March 2020.


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Do Tipping Points mean Runaway Global Warming after 12 years?

Is it 12 years?

That’s a belief I am finding increasingly common, but it really isn’t what the science is telling us.

The science is saying that things are very serious and every year we fail to “bend the curve down” as Greta Thunberg puts it, the worse the outcomes. We know from the IPCC (Intergovernmental Panel on Climate Change) 1.5oC Special Report that 2oC is significantly, perhaps surprisingly, worse than 1.5oC.

That is not a reason for a dystopian view that all is lost if we fail to get to zero after 12 (or is it now 11 years) if we don’t get to net zero by then.

The science is not that certain. The IPCC said that 2030 global net emissions must reduce by 45% versus 2010 emissions to achieve 1.5oC, and get to zero by 2050.

That is not to say we should not have highly ambitious targets, because the sooner we peak the atmospheric concentration of CO2 in the atmosphere, the sooner we peak the global warming (see Note 1).

Because it is such a huge challenge to decarbonise every sector of our economies, we should have started 30 years ago, and now we have to move very fast; whatever date you put on it. So, if I question some of the dystopian memes out there it is certainly not to question the need for urgent action.

Feedbacks and Tipping Points

I think what lies at the root of the dystopian message is a belief that tipping points – and there are quite a number in the Earth system – are like dominoes, and if one goes over, then all the rest follow. At a meeting I went to that included policy experts, XR, scientists, and others, I got into a chat about feedbacks and tipping points.

The person I spoke to was basically 100% convinced that if we did not get to net zero after ’12 years’ we would set off feedbacks and tipping points. It really would be game over. I want to summarise my side of the conversation:

I appreciate your concern about tipping points; they are real and need to be taken into account.

It is complicated and there are cases that can runaway (take Venus), but there is often a response that limits a particular feedback.

For example, extra CO2 causes warming, which due to the Clausius–Clapeyron relation means that additional water vapour (gaseous form of water, not clouds) is added to the atmosphere (7% extra for every 1C of warming). Since H2O is also a strong greenhouse gas that causes more warming.

This is a crucial ‘fast feedback’ included in climate models. It means that the expected 3oC of warming from doubling CO2 in the atmosphere is actually 1oC from the CO2 and 2oC extra from the H2O feedback (see Note 2).

Ok, so why doesn’t this warming carry on as a runaway (there is plenty of water in the ocean)?

The reason is Stefan’s Law (or ‘Planck Response’).

A body at temperature T emits energy at a rate proportional to T to the power 4. So the loss of heat accelerates and this at some points stops the feedback process (see Note 3).

A way to think about this is a plastic container with a hole at the bottom (say 7mm wide). Pour water from a tap at a constant rate, say half a litre per minute, into the container. What happens? The water level in the container rises to a point that maintains this level. At this point the pressure at the base of the container has increased to the point that the rate of flow of water out of the bottom is equal to the rate of flow in. They are in balance, or ‘equilibrium’.

If I now plug the 7mm hole and drill a 6mm one instead (yes I did this for a talk!), then with the same flow rate coming in, the level of water rises, because it requires more pressure at the base to drive water out at the rate required, to bring the system back into balance (when the level of water stops rising).

We are in both cases having the same amount of energy leaving as entering the system, but in the latter case, energy has been trapped in the system. 

This is a very good analogy for what happens with the Greenhouse Effect (see Note 4), and the level of water is analogous to the trapped energy (which means a hotter planet), and the world warms even though the rate at which energy is coming in (from the Sun) is constant. We can explain the Greenhouse Effect via this analogy simply:

The increased heat trapping power of the atmosphere with an increased concentration of COrestricts the exiting (infra-red) radiation to space – this is analogous to the reduced hole size in the container – and so …

The temperature of the Earth rises in order to force out radiation at the correct rate to balance the incoming energy – this is analogous to the increased level of water in the container. 

This demonstrates that the planet must stabilise the flow of energy out so that it equals the energy in, but with extra energy behind captured in the process (see Note 5).

The main point is that feedbacks do not inevitably mean there is a runaway.

Professor Pierrehumbert wrote a paper reviewing the possibility of a runaway in the sense of heading for a Venus scenario, and it seems unlikely “it is estimated that triggering a runaway under modern conditions would require CO2 in excess of 30,000 ppm”.

Even in more complex cases, such as melting sea ice and ice sheets, the feedbacks do not imply inevitable runaway, because in each case there is often a compensating effect that means a new equilibrium is reached.

But there is not one possible end state for a particular level of warming, there are numerous ones, and we know from the climate record that flips from one state to another can happen quite fast (the ocean conveyor belt transports huge amounts of heat around the planet and this is often implicated in these rapid transitions).

So, this is not to say that the new equilibirum reached is a good place to end up. Far from it. I agree it is serious, and the level of CO2 in the atmosphere is now unprecedented for over 3 million years. We are warming at an unprecedented rate, thousands of times faster than the Earth has seen in that period.

It is very scary and we don’t need to say a runaway is inevitable to make it even more scary!

Arguments that a feedback will trigger another, and so on, ad infinitum, may sound plausible but are not science, however confident and high profile the speaker may be. It does the XR cause no good to simply repeat wild speculation that has no scientific foundation, merely on the basis of a freewheeling use of the ‘precautionary principle’.

I hope this clarifies my point, which was not to minimise the urgency for action – far from it – I am 100% behind urgent action.

However, I think that sometimes it is important to be scientifically pedantic on the question of feedbacks and runaway. The situation is scary enough.

I really worry about the dystopian message for our collective mental health, and that this might freeze people and even limit action amongst the wider public who are not activitists (but need to participate in our collective actions).

We need a message of hope, and this is it:

The sooner we can peak the atmospheric concentration of CO2 (by stopping emissions), the sooner we can halt warming, and

the lower that peak in the atmospheric concentration, the lower the level of warming.

We can make a difference!

We have to act to make hope meaningful, because being alarmed, and frozen in the headlights, and unable to act, is not a recipe for hope.

However, being duly alarmed and having hope are not mutually exclusive, if we recognise we have agency. We can all make a contribution, to agitate for, or implement, a plan of actions and the actions that follow.

(c) Richard W. Erskine, 2019



(1)   The IPCC 1.5C Special Report (p.64) talks about ‘committed warming’ in the oceans that is often assumed to mean that the Earth will continue to warm even when we stop CO2 emissions due to thermal inertia of heated oceans. Surprisingly for many, this is not the case. The IPCC reiterate what is a long known effect, regarding what they term the Zero Emissions Commitment:

“The ZEC from past COemissions is small because the continued warming effect from ocean thermal inertia is approximately balanced by declining radiative forcing due to COuptake by the ocean … Thus, although present-day CO2-induced warming is irreversible on millennial time scales … past COemissions do not commit substantial further warming”

(2)   This excludes clouds, and the effect of clouds at lower and higher levels can, for this simple example, can be regarded as cancelling each other out in terms of warming and cooling. Water Vapour in the atmosphere referred to here is not condensed into droplets but is a gas that is transparent to the human eye, but like carbon dioxide, is a strong absorber of infra-red. Because carbon dioxide is a non-condensing gas, but water does condense, it is the concentration of carbon dioxide that is the ‘control knob’ when it comes to their combined warming effect.  In 1905, T.C. Chamberlin writing to Charles Abbott, eloquently explains the feedback role of water vapour, and the controlling power of carbon dioxide:

“Water vapour, confessedly the greatest thermal absorbent in the atmosphere, is dependent on temperature for its amount, and if another agent, as CO2 not so dependent, raises the temperature of the surface, it calls into function a certain amount of water vapour, which further absorbs heat, raises the temperature and calls forth more [water] vapour …”

(3)  Strictly, it is a ‘black body’ – that absorbs (and emits) energy at all frequencies – that obeys Stefan’s Law. When using the law, we express T in Kelvin units. To a reasonable approximation, we can treat the Earth as a black body for a back of the envelope calculation, and we find that without carbon dioxide in the atmosphere, the Earth – at its distance from the sun – would be 258K, or -15oC on average, a frozen world. That would be 30oC colder than our current, or pre-industrial, average of 15oC.

(4) John Tyndall originated this analogy in his memoirs Contributions to Molecular Physics in the Domain of Radiant Heat published in 1872, although he used the example of a stream and dam, which is raised, my exposition is essentially based on his precedent.

(5) One other aspect of this re-established equilibrium is that the so-called ‘Top of Atmosphere’ (TOA) – where the energy out in the form of infra-red, is balancing the energy in – is at higher altitiude. The more carbon dioxide we add, the higher this TOA. Professor Pierrehumbert explains it in this Youtube exposition, from the film Thin Ice, where he pulls in a few other aspects of the warming process, as it works on planet Earth (e.g. convection).



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Google and the Internet: Friend or Foe to the Planet?

I keep hearing this meme that goes along the lines of “a Google search will use X amount of energy”, where X is often stated in a form of a scary number.

I think numbers are important.

According to one source a Google search is about 0.0003 kWh of energy, whereas a 3kW kettle running for one minute uses 3 x (1/60) = 1/20 = 0.05 kWh, which is 160 times as much (another piece  uses an equivalent figure – Note 1).

On the UK grid, with a carbon intensity of approximately 300 gCO2/kWh (and falling) that would equate to 0.09 gCO2 or roughly 0.1 gCO2 per search. On a more carbon intensive grid it could be double this, so giving 0.2 gCO2 per search, which is the figure Google provided in response to The Sunday Times article by MIT graduate Alex Wissner-Gross (cited here), who had estimated 7 gCO2 per search.

If the average Brit does the equivalent of 100 searches a day, that would be:
100 x 0.0003 kWh = 0.03 kWh, whereas according to Prof. Mackay, our total energy use (including all forms) is 125 kWh per person per day in UK, over 4,000 times more.

But that is not to say the that the total energy used by the Google is trivial.

According to a Statista article, Google used over 10 teraWatthours globally in 2018 (10 TWh = 10,000,000,000 kWh), a huge number, yes.

But the IEA reports  that world used 23,000 TWh in 2018. So Google searches would represent about 0.04% of the world’s energy on that basis, a not insignificant number, but hardly a priority when compared to electricity generation, transport, heating, food and forests. Of course, the internet is more than simply searches – we have data analysis, routers, databases, web sites, and much more. Forbes published findings from …

A new report from the Department of Energy’s Lawrence Berkeley National Laboratory figures that those data centers use an enormous amount of energy — some 70 billion kilowatt hours per year. That amounts to 1.8% of total American electricity consumption.

Other estimates indicate a rising percentage now in the low few percentage points, rivalling aviation. So I do not trivialise the impact of the internet overall as one ‘sector’ that needs to address its carbon footprint.

However, the question naturally arises, regarding the internet as a whole:

how much energy does it save, not travelling to a library, using remote conferencing, Facebooking family across the world rather than flying, etc., compared to the energy it uses?

If in future it enables us to have smarter transport systems, smart grids, smart heating, and so on, it could radically increase the efficiency of our energy use across all sectors. Of course, we would want it used in that way, rather than as a ‘trivial’ additional form of energy usage (e.g. hosting of virtual reality game).

It is by no means clear that the ‘balance sheet’ makes the internet a foe rather than friend to the planet.

Used wisely, the internet can be a great friend, if it stops us using planes, over-heating our homes, optimising public transport use, and so forth. This is not techno-fetishism, but the wise use of technology alongside the behavioural changes needed to find climate solutions. Technology alone is not the solution; solutions must be people centred.

Currently, the internet – in terms of its energy use – is a sideshow when it comes to its own energy consumption, when compared to the other things we do.

Stay focused people.

Time is short.

(c) Richard W. Erskine, 2019


Note 1

I have discovered that messing about with ‘units’ can cause confusion. So here is an explainer. The cited article uses a figure of 0.3 Watt hours, or 0.3 Wh for short. The more commonly used unit of energy consumption is kilo Watt hours or kWh. As 1000 Wh = 1 kWh, so it remains true if we divide both sides by 1000: 1 Wh = 0.001 kWh. And one small step means 0.1 Wh = 0.0001 kWh. Hence, 0.3 Wh = 0.0003 kWh.  If you don’t spot the ‘k’ things do get mighty confusing!


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Fusion is the Future

I mean it, it is the future.

Or rather, to be accurate, it could be the future.

In the core of the sun, the energy production is very slow, thankfully, so the beast lasts a long time. You need about 10,000,000,000,000,000,000,000,000,000,000 collisons between hydrogen nuclei before you get 1 that successfully fuses, and releases all that energy.

Beating those odds in a man-made magnetic plasma container (such as a Tokamak) is proving to be something that will be done by tomorrow, plus 50 years (and repeat).

Boris Johnson obviously believes that the way to show a flourish of leadership is to channel dreams of technical wizardry that goes well beyond the briefings from those experts in the know.

But who believes in experts in magneto-hydrodynamics? Stop over complicating the story you naysayer PhDs. Positive mental attitude will confound physics! Get back in your box experts!


Man-made fusion energy as an answer to the man-made climate emergency by 2040 is not just ignorant, it is a deliberate and cynical attempt to delay action now. It is a form of techno-fetishism that deniers love. Boris Johnson spends a lot of time with these people.

We have relevant solutions available today, and just need to get on with them.

We do indeed have a functionally infinite fusion energy generator available to humanity, and it is free.

It’s called ‘The Sun’ (an astronomical entity, not a rag masquerading as a newspaper).

If man-made fusion energy is commercialised it *MAY BE* relevant to a world *POST*  resolving the climate crisis, but is definitely not part, or even maybe part, of that resolution.

It fails key tests I discussed here

Please politicians – left, right and centre – stop playing games and take the climate emergency seriously.

It may surprise you that while Boris’s cult following will swallow anything (almost literally), the rest, and particularly the rising youth, will not.

But I am prepared to compromise. A deal is possible.

Fusion is indeed the future …

… it is the energy from the Sun!

And you might be surprised to hear that it gives rise to …

direct Photovoltaic (PV) capture of that energy,

and indirect forms of capture (e.g. wind energy).

Problem solved.

As to man-made fusion, the jury is out (and a distraction for now), and we don’t have time to wait for the verdict.


(c) Richard W. Erskine. 2019

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Renewable Technologies: Facts, Fiction and Current Developments

Chris Wilde, Managing Director of Yorkshire Energy Systems (YES), gave a talk Renewable Technologies: Facts, Fiction and Current Developments on 5th September 2019 at The Arkell Centre in Nailsworth, hosted by Nailsworth Climate Action Town (NCAT). The focus was on domestic renewables in UK.

Chris exploded many myths and misunderstandings that even some supporters of renewables believe in. The audience included an influential range of people, from the national political level, to district and parish councillors, from Transition Stroud, local climate groups, Severn Wye Energy Agency, and local renewable energy businesses. It was an excellent talk and very well recieved.

I will be sharing a fuller record of the talk, but to briefly summarise his words that accompanied the pictures used in the talk, using my notes …

Whereas 5 years ago, or even 6 months ago, the majority of householders installing renewables were doing it simply for financial reasons, rather than to reduce their carbon footprint, that has now changed, and about half of those now doing it are motivated by concerns about global warming. Greta Thunberg and Extinction Rebellion can take a lot of credit for raising awareness.

Chris showed an aerial view of a large 110 kW (kilowatt, a unit of ‘power’) solar PV system YES did for a company close to Wembley Stadium. What is shocking is that there are huge areas of commercial roof space without solar surrounding this installation. As Chris said, it shouldn’t be a question of seeking permission to have solar – particularly on new homes or new commercial buildings – it should be required that they do have solar, and it is much cheaper to do it at build time than to retrofit later (“solar” will be used as shorthand for solar photovoltaic (PV) in the text below):

Solar Myths

Myth 1 – Solar is ugly. Leaving aside the point that saving the planet might be seen as more important than the aesthetics of roof lines, the fact is solar panels have been getting slicker and more aesthetic. It is now possible to replace tiles completely with in-roof panels.

Myth 2 – You can only have 4kW on your installation. No, you can only have 4kW per phase before seeking permission from the grid (kW here mean kWp, the peak kW power achievable).

Myth 3 – Cannot have solar without a south facing roof. Actually, the variation in input from west or east, versus south, facing panels can be as little as 15%, and in fact having east and west facing panels can be better for households needing more energy in the morning and afternoon. On flat roofs, you can pack east and west panels more tightly (because less spacing is then required to deal with shadowing effects), and this completely compensates for not being south facing.

Myth 4 – We don’t have a roof that is not shaded, so pointless. Ok, but there are other options, such as ground mounted arrays, or a tracking system like Heliomotion (which has a UK base in Stroud). Chris also showed arrays mounted high enough for sheep to graze under; and there is even a trend now to place solar on top of parking bays. There are simply so many ways of having solar fitted, there are no excuses for not doing it!

Myth 5 – The Feed In Tarif (FIT) has ended so it cannot be made to work, financially. This is wrong on several levels.

  • Firstly, the sun’s energy is free.
  • Secondly, the price of solar panels has dropped while their performance has increased (output increased from 250W to 350W over 5 years).
  • Thirdly, it is true that FIT gave householders 40p per kWh (kiloWatt hour, a unit of ‘energy’) for all energy generated, whether exported to the grid or not, and an extra 3p per kWh for 50% of that generated that is assumed to be exported to the grid. However, while there are now no FIT payments, utility companies will have to pay for what you export, under the new Export Guarantee Scheme (Octopus are already offering 5.5p per kWh even before the scheme comes in).
  • Fourthly, with a low cost ‘solar diversion switch’ any excess solar energy can be used to heat hot water, avoiding the need to export it to the grid (and by the way, this simple device has essentially killed the ‘solar thermal’ market).
  • Fifthly, systems that were costing between £3,000 and £4,000 per kW are now down to £1,000. So, in short, payback of a solar system is still possible within 6-7 years even without the FIT subsidy.
  • Finally, the reduction in bureaucracy with the loss of FIT means that it actually might, paradoxically, accelerate uptake of solar.

Heat Pump Myths

Chris started by explaining how heat pumps work, which seems miraculous to many people, but is the product of 17th century physics: if you compress a gas, it gets hotter. And a heat pump works by transferring heat from the air (or ground) via a fluid (a refrigerant) that is compressed and then releases its heat inside the building. But for each unit of energy used by the pump, 3 to 4 units of energy is extracted from the air in the form of heat. The two main categories of heat pump are Air Sourced Heat Pumps (ASHP) and Ground Sourced Heat Pumps (GSHP). The efficiency of a heat pump will vary with external temperature, but overall is quoted as a seasonally averaged figure.

Assume you had an ASHP with 3.5 efficiency factor. If you have a heating requirement of 18,000 kWh for your home, this could be achieved by using 18,000/3.5 = 5,143 kWh of electricity. Mains gas is currently 3p per kWh and mains electricity is 13 p per kWh so to heat the house with gas would be 18,000 x £0.03 = £540 per year, whereas to do it with this ASHP would be 5,143 x £0.13 = £669; still a bit more than gas, because gas is currently ridiculously cheap, but a few things to consider:

  • when a crisis occurs in the Middle East for example, gas prices can rise, and don’t have to swing much to wipe out the current distorted advantage of cheap gas;
  • a tax on carbon including gas, will come sooner or later to reflect the damage that carbon dioxide emissions are doing;
  • even if today some electricity is coming from fossil fuel plants, increasingly the grid is being ‘greened up’ (see to look at how much the grid has already greened);
  • as you will see below, if you add solar to a heat pump the maths flips, because you can use the free solar electricity to help drive the heat pump and even if that is not all year round, 24-7, it has made a huge difference;
  • finally, if you cannot add solar to your heat pump for some reason, many people are prepared to pay an extra £100 or so per year to save the planet (that is clear from the recent boost in heat pump installations YES have been seeing).

One other key point is that heating a house using a heat pump requires sufficiently large radiators because it operates using a flow temperature of 45/50oC, rather than say 70oC as with a gas boiler. At 45/50oC they still heat the house to the required temperature (typically 21oC), but does so with a larger surface area of ‘emitter’ (this effectively means a slight fatter radiator, and depending on how old the heating system in a house is, that may mean that some of the radiators need to be upgraded, but rarely all radiators; even better, under floor heating can be used, increasing the area even more).

Myth 6 – It cannot work when it is cold outside. Yes it can, as described. It is basic physics at work, and no magic is involved!

Myth 7 – They are more expensive than a gas boiler, so are unaffordable. Heat pumps are more expensive to fit but the Renewable Heat Incentive (RHI) was designed precisely to deal with this. It is paid to the householder over 7 years (and commercially over 20 years), reducing running costs and overall, paying off half to two-thirds of the cost of the installation. To qualify for RHI, the key requirement is roof insulation, and if you have cavity walls, then cavity wall insulation.

Myth 8 – They cannot work in old leaky houses. Untrue. Chris presented an example of an old rectory with 290 square metre floor area, that had good roof insulation but with walls that could not be clad, and overall it was a high heat loss building. It cost £3,500 per year using an oil boiler to heat it. Using a brilliantly effective combination of a 10kW solar array and 6 under lawn ‘slinkies’ to feed a GSHP, the heating bill dropped to £1,500 per year.
That is despite the heating system being set to ‘on’ all the time (but obviously, with a thermostat it runs only when the temperature drops below the required temperature). The 80 year old grand mother loves visiting the house now because “it is always so cosy”. Chris is not saying, from this experience, that insulation is unimportant – it is crucial you get good insulation – but where it is not up to modern standards, don’t let that be a reason for not installing renewable heat: That is, a heat pump with or without solar, but preferably with because the solar reduces the amount of electricity used from the grid, and swings the maths in favour of heat pumps (versus gas).

Chris gave another example of a bungalow (177 square metre floor area) that was costing £1,551 per year to heat. With just a 4 kW roof mounted system and a 14 kW ASHP the bill came down to £903. Now this was £168 more saving than they had expected. Why? Chris believes this is down to behavioural change. Instead of the behaviour with traditional gas systems which can heat up a house fast, and people switch up the system when cold and down when hot – creating a see-saw effect – with heat pump systems, people can just keep it on and be comfy at a sensible temperature (whichever is their preference). Increasingly, Chris is persuading householders to refrain from fiddling with the heat controls and allow the system to work as pre-programmed and provide consistent, comfortable but not hotter than required levels of heating. This changes behaviour and actually creates a perception of a cosier home and reduced bills; what is not to like?

The caveat is that we need more skilled fitters who do not put in the wrong sized radiators, or pipe work, and of course householders who don’t leave doors open (trying to heat your local town is not a sensible approach!).

Renewable technologies like solar and heat pumps are not rocket science, but a basic knowledge is required and vendors are very good at providing training. Along with persuading householders to take the plunge we also need to transfer trade skill sets, to acquire the knowledge and experience to help increase adoption. If your plumber says they don’t know anything about heat pumps, encourage them to take a course – to unlearn some old ways and learn some new ways – and they might be in the vanguard of the change to renewable heat in your neighbourhood.

Chris also mentioned that he has found an issue related to Energy Performance Certificates (EPCs). The question Chris is asking Government is this:

Why is it that it is government policy to encourage the installation of heat pumps through the Renewable Heat Incentive scheme, yet EPCs never recommend them and even discourage them by predicting higher running costs for heat pumps even than old oil boilers contrary to the research carried out by the government in 2013 on which the RHI was based? Does the left hand not know what the right hand is doing?

Chris has written a paper EPCs: A MAJOR OBSTACLE TO HEAT PUMPS AND DECARBONISATION going into more detail on this issue, that can be found on the YES website.

Chris covered a number of other points and new developments such as thermal storage, but I hope this summary does justice to what was an excellent and inspiring talk.

We have a climate emergency – we need to start behaving like we actually believe it!

So let’s get to work, and make it happen! There is no excuse for not doing so.

This summary of Chris Wilde’s talk is based on my notes, so will be incomplete, as Chris is a brilliant speaker who doesn’t need a script or use bullet points. So, if any errors have crept in, naturally they are mine. Richard Erskine, 7th Sept. 2019. Any comments please provide via my blog.

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The Curious Case of Heat Pumps in the UK

Heat Pumps, whether Air-Sourced or Ground-Sourced, can and should be making a major contribution to decarbonising heating in the UK. Heating (both space heating and water heating) is major contributor to our carbon footprint.

Heat pumps are now incredibly efficient – for 1 unit of electrical energy you put in you can get at least 3 units back in the form of heat energy (a pump compresses the air and this causes it to rise in temperature; two century old physics at work here).  The process works sufficiently well even in UK winters.

The pumps are now relatively quiet (think microwave level of noise). They can deliver good payback (even more so if there was a cost on carbon). They even work with older properties (countering another one of the many myths surrounding heat pumps).

I even heard Paul Lewis on BBC’s ‘Money Box’ (Radio 4) – clearly getting confused between heat pumps and geothermal energy – saying ‘oh, but you need to be in a certain part of the country to use them’ (or words to that effect).

We clearly need much more education out there to raise awareness of the potential of heat pumps.

When combined with solar (to provide some of the electricity), they are even better.

So why is the take-up of heat pumps still too slow? Why is the Government not pushing them like crazy (it is an emergency, right!)? Why are households, when replacing old boilers, till opting for gas?

When we had the AIDS crisis in the 1980s, the UK Government undertook a major health awareness campaign, and other countries also, which largely succeeded. In an emergency, Governments tend to act in a way that ‘signals’ it is an emergency.

The UK Government is sending no such signals. Bland assurances that the commitment to reach net zero by 2050 is not a substitute for actions. In the arena of heat, where is the massive programme to up-skill plumbers and others? Where is the eduation programme to demystify heat pumps and promote their adoptions?

And where is the joined up thinking?

This article below from Yorkshire Energy Systems, based on their extensive research and practical experience, suggests one reason – that EPCs (Energy Performance Certificates) issued for homes and including recommended solutions – are biased against heat pumps.

The mismatch between what the Government is saying (that heat pumps are part of the decarbonisation solution) and what EPCs are advising suggests a clear lack of joined up thinking.

… and no sign that the Government really believes that urgent action is required.

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Increasing Engineering Complexity and the Role of Software

Two recent stories from the world of ‘big’ engineering got me thinking: the massive delays in the Crossrail Project and the fatal errors in the Boeing 737 Max, both of which seem to have been blighted by issues related to software.

Crossrail, prior to the announcement of delays and overspend, was being lauded as an example of an exemplar on-time, on-budget complex project; a real feather in the cap for British engineering. There were documentaries celebrating the amazing care with which the tunnelling was done to avoid damage at the surface, using precise monitoring and accurately positioned webs of hydraulic grouting to stabilise the ground beneath buildings. Even big data was used to help interpret signals received from a 3D array of monitoring stations, to help to actively manage operations during tunnelling and construction. A truly awesome example of advanced engineering, on an epic scale.

The post-mortem has not yet been done on why the delays came so suddenly upon the project, although the finger is being pointed not at the physical construction, but the digital one. To operate the rail service there must be advanced control systems in place, and to ensure these operate safely, a huge number of tests need to be carried out ‘virtually’ in the first instance, to ensure safety is not compromised.

Software is something that the senior management of traditional engineering companies are uncomfortable with; in the old days you could hit a machine with a hammer, but not a virtual machine. They knew intuitively if someone told them nonsense within their chosen engineering discipline; for example, if a junior engineer planned to pour 1000 cubic metres of cement into a hole and believed it would be set in the morning. But if told that testing of a software sub-system will take 15 days, they wouldn’t have a clue as to whether this was realistic or not; they might even ask “can we push to get this done in 10 days?”.

In the world of software, when budgets and timelines press, the most dangerous word used in projects is ‘hope’. “We hope to be finished by the end of the month”; “we hope to have that bug fixed soon”; and so on  Testing is often the first victim of pressurised plans. Junior staff say “we hope to finish”, but by the time the message rises up through the management hierarchy to Board level, there is a confident “we will be finished” inserted into the Powerpoint. Anyone asking tough questions might be seen as slowing the project down when progress needs to be demonstrated.

You can blame the poor (software) engineer, but the real fault lies with the incurious senior management who seem to request an answer they want, rather than try to understand the reality on the ground.

The investigations of the Boeing 737 Max tragedy are also unresolved, but of course, everyone is focusing on the narrow question of the technical design issue related to a critical new feature. There is a much bigger issue at work here.

Arguably, Airbus has pursued the ‘fly by wire’ approach much earlier than Boeing, whose culture has tended to resist over automation of the piloting. Active controls to overcome adverse events has now become part of the design of many modern aircraft, but the issue with the Boeing 737 Max seems to have been that this came along without much in the way of training; and the interaction between the automated controls and the human controls is at the heart of the problem. Was there also a lack of realistic human-centric testing to assess the safety of the combined automated/ human control systems? We will no doubt learn this in due course.

Electronics is of course not new to aerospace industries, but programmable software has grown in importance and increasingly it seems that the issue of growing complexity and how to handle the consequent growth in testing complexity, has perhaps overtaken the abilities of traditional engineering management systems. This is extending to almost every product or project – small and large – as the internet of everything emerges.

This takes me to a scribbled diagram I found in an old notebook – made on a train back in 2014, travelling to London, while I debated the issue of product complexity with a project director for a major engineering project. I have turned this into the Figure below.

Screenshot 2019-08-14 at 19.30.09

There are two aspects of complexity identified for products: 

  • Firstly, the ‘design complexity’, which can be thought of as the number of components making up the product, but also the configurability and connectivity of those components. If printed on paper, you can thinking of how high the pile of paper would be that identified every component, with a description of their configuration and connection. This would apply to physical aspects but also software too; and all the implied test cases. There is a rapid escalation in complexity as we move from car to airliner to military platform.
  • Secondly, the ‘production automation complexity’, which represents the level of automation involved in delivering the required products. Cars as they have become, are seen as having the highest level of production automation complexity. 

You can order a specific build of car, with desired ‘extras’, and colour, and then later see it travelling down the assembly line with over 50% of the tasks completely automated; the resulting product with potentially a nearly unique selection of options chosen by you. It is at the pinnacle of production automation complexity but it also has a significant level of design complexity, albeit well short of others shown in the figure. 

Whereas an aircraft carrier will in each case be collectively significantly different from any other in existence (even when originally conceived as a copy of an existing model) – with changes being made even during its construction – so does not score so high on ‘production automation complexity’. But in terms of ‘design complexity’ it is extremely high (there are only about 20 aircraft carriers in operation globally and half of these are in the US Navy, which perhaps underlines this point).

As we add more software and greater automation, the complexity grows, and arguably, the physical frame of the product is the least complex part of the design or production process. 

I wonder is there a gap between the actual complexity of the final products and an engineering culture that is still heavily weighted towards the physical elements – bonnet of a car, hull of a ship, turbine of a jet engine – and is this gap widening as the software elements grow in scope and ambition? 

Government Ministers, like senior managers, will be happy being photographed next to the wing of a new model of airliner – and talk earnestly about workers riveting steel – but what may be more pivotal to success is some software sub-system buried deep in millions of lines of ‘code’; no photo opportunities here.

Screenshot 2019-08-14 at 19.30.27

As we move from traditional linear ‘deterministic’ programming to non-deterministic algorithms – other questions arise about the increasing role of software. 

Given incomplete, ambiguous or contradictory inputs the software must make a choice about how to act in real time. It may have to take a virtual vote between independently written algorithms. It cannot necessarily rely on supplementary data from external sources (“no, you are definitely nose diving not stalling!”), for system security reasons if not external data bandwidth reasons.

And so we continue to add further responsibility, onto the shoulders of the non-physical elements of the system.

Are Crossrail and the 737 Max representative of a widening gap, reflected in an inability of existing management structures to manage the complexity and associated risks of the software embedded in complex engineering products and projects? 

© Richard W. Erskine, 2019

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Boris loves Corbyn

No not Jeremy; his brother.

For some years now Boris Johnson has channelled the crank theories of Piers Corbyn, who appeared in the 2007 film The Great Global Warming Swindle, which was shown to be ill-founded.

Rather like the myth that carrots helped RAF pilots see at night during WWII  which was such a great story that even today it is repeated and believed, the idea that some changes in the Sun’s output is responsible for recent climate change is a similarly attractive myth, which keeps on being repeated.

The BBC had to apologise for Quentin Letts’ execrable hatched job on the Met Office in 2015, which also included Piers Corbyn. 

The truth is that we know with a confidence unsurpassed in many fields of science what is causing global warming; it’s not the sun, it’s not volcanoes; it’s not contrails. The IPCC’s 5th Assessment Report (2013) was clear that greenhouse gases (principally carbon dioxide) resulting from human activities are the overwhelming driver of global warming (see Figure 8.15)

So you might expect Boris Johnson as a leading politician, to reference the IPCC (Intergovernmental Panel on Climate Change), which gathers, analyses and synthesises the published work of thousands of scientists with relevant expertise on behalf of the nations of the world.

Instead, he has referred to the “great physicist and meteorologist Piers Corbyn” (It’s snowing, and it really feels like the start of a mini ice age, Boris Johnson, Daily Telegraph, 20th January 2013). Piers Corbyn has no expertise in climate science and theories like his have been completely debunked in a paper published in the Proceedings of The Royal Society:

… the long-term changes in solar outputs, which have been postulated as drivers of climate change, have been in the direction opposite to that required to explain, or even contribute to, the observed rise in Earth’s global mean air surface temperature (GMAST) …

What is alarming is that in the face of this strong scientific evidence, some Internet sources with otherwise good reputations for accurate reporting can still give credence to ideas that are of no scientific merit. These are then readily relayed by other irresponsible parts of the media, and the public gain a fully incorrect impression of the status of the scientific debate.

“Solar change and climate: an update in the light of the current exceptional solar minimum”, Proceedings of The Royal Society A, Mike Lockwood, 2nd December 2009

So, for Boris Johnson to call himself an “empiricist” is, frankly, laughable.

He has also cozied up to neoliberal ‘think tanks’ implacably opposed to action on global warming. 

I think we can safely say that hitherto he has firmly placed himself in the DENIAL bucket (in the illustration below).

Screenshot 2019-07-29 at 21.24.30

He shares this perspective with other hard Brexiteers in the new Cabinet, who are itching to deregulate the UK economy, such as Jacob Rees-Mogg, and see action on global warming as a constraint on unregulated markets.

In his acceptance speech on becoming Prime Minister, Boris Johnson never mentioned climate change. But since then he has reiterated Theresa May’s Government’s commitment to net zero by 2050, and

Responding to concerns expressed by Shadow Treasury Minister Anneliese Dodds that he had not focused sufficiently climate change in the initial statements outlining his priorities as Prime Minister, Johnson replied: “The House will know that we place the climate change agenda at the absolute core of what we are doing.”

(edie, 29th July 2019)

He went on to say

He said: “This party believes in the private sector-generated technology which will make that target attainable and deliver hundreds of thousands of jobs. That is the approach we should follow.” …

Predicting that the UK will “no longer” be contributing to climate change by 2050, Johnson said: “We will have led the world in delivering that net-zero target. We will be the home of electric vehicles—cars and even planes—powered by British-made battery technology, which is being developed right here, right now.”

(edie, 29th July 2019)

By imagining that industry alone (without any stated plans for an escalating tax on carbon), can somehow address the huge transformation required, on the timescale required, without concerted effort at every level of Government (top down and bottom up), and civil society, he remains disconnected from reality, let alone science.

Moving from DENIAL to COMPLACENCY is an advance for Boris – assuming for the moment this is not another flip-flopping of positions that he is famed for – but it is hardly the sign of the climate leadership required. We need a leadership that respects the science, and understands the policy implications and prescriptions required.

Did anyone in the house ask the Prime Minister if he accepts and will fully support the recommendation of the Climate Change Committee’s report Net Zero – The UK’s contribution to stopping global warming? 

They need to, because great words need to turned into a plan of action, and every year we delay will make the transition more painful (it is already going to be painful enough, but they are not telling you that, are they?).

That will not be enough to meet the public’s concerns over the climate emergency, and increasingly, the public will be expecting leadership that has moved from COMPLACENCY to the URGENCY position.

Many see GREEN RADICALISM as now an unavoidable response to the COMPLACENCY in Whitehall.

If Boris Johnson fails to jettison his neoliberal friends and the crank science that is part of their tool-kit – who are trying (and have succeeded so far) in putting the breaks on meaningful and urgent action – the longer term political fall-out will make Brexit look like a tea party.

(c) Richard W. Erskine,, July 2019


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The Climate Change Committee just failed to invent a time machine

These past two weeks have been such a momentous time for climate change in the UK it is hard to take in. My takes:

On 21st April, Polly Higgins, the lawyer who has spent a decade working towards establishing ecocide as a crime under international law, sadly died. At a meeting at Hawkwood Centre, Stroud, I heard the inspiring Gail Bradbrook speak of how Polly had given her strength in the formation of Extinction Rebellion. 

On 23rd April, Greta Thunberg spoke to British Parliamentarians with a clear message that “you did not act in time’, but with imagination and some ‘Cathedral thinking’ it is not too late to act (full text of speech here).

On 30th April, Extinction Rebellion met with the Environment Secretary Michael Gove, a small step but one that reflects the pressure that their actions (widely supported in the country) are having. Clare Farrell said the meeting “.. was less shit than I thought it would be, but only mildly”, but it’s a start.

On 1st May, the UK’s Parliament has declared a climate emergency

On 2nd May the Committee on Climate Change (CCC), setup under the 2008 Climate Change Act, has published its report “Net Zero – The UK’s contribution to stopping global warming” to the Government on how to reach net zero by 2050.

These are turbulent times. Emotions are stirring. Expectations are high. There is hope, but also fear.

The debate is now raging amongst advocates for climate action about whether the CCC’s report is adequate.

Let’s step back a moment.

The IPCC introduced the idea of a ‘carbon budget’ and this is typically expressed in the form such as (see Note):

“we have an X% chance of avoiding a global mean surface temperature rise of  Y degrees centigrade if our emissions pathway keeps carbon emissions below Z billion tonnes”

The IPCC Special 1.5C Report, looked at how soon we might get to 1.5C and the impacts of this compared to 2C. As Carbon Brief summarised it:

At current rates, human-caused warming is adding around 0.2C to global average temperatures every decade. This is the result of both “past and ongoing emissions”, the report notes.

If this rate continues, the report projects that global average warming “is likely to reach 1.5C between 2030 and 2052”

Perhaps the most shocking and surprising aspect of this report was the difference in impacts between 1.5C and the hitherto international goal of 2C. The New York Times provided the most compelling, graphic summary of the change in impacts. Here are a few examples:

The percentage of the world’s population exposed to extreme heat jumps from 14% to 37%

Loss of insect species jumps from 6% to 18%

Coral reefs suffer “very frequent mass mortalities” in a 1.5C world, but “mostly disappear” in a 2C world.

So, in short, 1.5C is definitely worth fighting for.

In view of the potential to avoid losses, it is not unreasonable for Extinction Rebellion and others to frame this as a “we’ve got 12 years”. The IPCC says it could be as early as 12 years, but it might be as late as 34 years. What would the Precautionary Principle say? 

Well, 12 years of course.

But the time needed to move from our current worldwide emissions to net zero is a steep cliff. You’ve all seen the graph.


It seems impossibly steep. It was a difficult but relatively gentle incline if we’d started 30 years ago. Even starting in 2000 was not so bad. Every year since the descent has  become steeper. It is now a precipice.

It is not unreasonable to suggest it is impossibly steep.

It is not unreasonable to suggest we blew it; we messed up.

We have a near impossible task to prevent 1.5C.

I’m angry about this. You should be too.

I am not angry with some scientists or some committee for telling me so. That’s like being angry with a doctor who says you need to lose weight. Who is to blame: the messenger? Maybe I should have listened when they told me 10 years back.

So if the CCC has come to the view that the UK at least can get to net zero by 2050 that is an advance – the original goal in the Act was an 80% reduction by 2050 and they are saying we can do better, we can make it a 100% reduction.

Is it adequate?

Well, how can it ever be adequate in the fundamental sense of preventing human induced impacts from its carbon emissions? They are already with us. Some thresholds are already crossed. Some locked in additional warming is unavoidable.

Odds on, we will lose the Great Barrier Reef.  Let’s not put that burden on a committe to do the immpossible. We are all to blame for creating the precipice.

That makes me sad, furious, mournful, terrified, angry.

There is a saying that the best time to have started serious efforts to decarbonise the economy was 30 years ago, but the next best time is today.

Unfortunately, the CCC does not have access to a time machine.

Everyone is angry.

Some are angry at the CCC for not guaranteeing we stay below 1.5C, or even making it the central goal. 

Extinction Rebellion tweeted:

The advice of @theCCCuk to the UK government is a betrayal of current & future generations made all the more shocking coming just hours after UK MPs passed a motion to declare an environment & climate emergency. 

It is I think the target of 2050 that has angered activists. It should be remembered that 2050 was baked into the Climate Change Act (2008). It should be no surprise it features in the CCC’s latest report. The CCC is a statutory body. If we don’t like their terms of reference then it’s easy: we vote in a Government that will revise the 2008 Act. We haven’t yet achieved that.

Professor Julia Steinberger is no delayist (quite the opposite, she’s as radical as they come), and she has tweeted back as follows:

Ok, everyone, enough. I do need to get some work done around here.

(1) stop pretending you’ve read & digested the whole CCC net-zero report. It’s 277 pretty dense pages long. 

(2) there is a lot of good stuff & hard work  making the numbers work there.  

3) Figuring out what it means for various sectors, work, finance, education, training, our daily lives & cities & local authorities and so on is going to take some thinking through.

(4) If you want a faster target, fine! I do too! Can you do it without being horrid to the authors and researchers who’ve worked like maniacs to try to get this much figured out? THEY WANT TO BE ON YOUR SIDE! 

(5) So read it, share it, reflect on it, and try to figure out what & how we can do a lot faster, and what & how we can accelerate the slower stuff.

Treat the CCC report as in reality an ambitious plan – it really is – in the face of the precipice, but also believe we can do better.

These two ideas are not mutually exclusive.

Maybe we do not believe that people can make the consumption changes that will make it possible to be more ambitious; goals that politicians might struggle to deliver.

Yet communities might decide – to hell with it – we can do this. Yes we can, do better.

Some are scornful at Extension Rebellion for asking the impossible, but they are right to press for better. However, can we stop the in-fighting, which has undermined many important fights against dark forces in the past. Let’s not make that mistake again.

Can we all be a little more forgiving of each other, faced with our terrible situation.

We are between a rock and a hard place.

We should study the CCC report. Take it to our climate meetings in our towns, and halls, and discuss it. 

How can we help deliver this?

How can we do even better?

I for one will be taking the CCC report to the next meeting of the climate action group I help run.

I’m still mournful.

I’m still angry.

But I am also a problem solver who wants to make a difference.

Good work CCC.

Good work XR.

We are all in this together.

… and we don’t have a time machine, so we look forward.

Let not the best be the enemy of the good.

Let not the good be a reason for not striving for better, even while the best is a ship that has long sailed.

© Richard W. Erskine, 2019



You pick an X and Y, and the IPCC will tell how much we can emit (Z). The ‘X%’ is translated into precisely defined usages of terms such as ‘unlikely’, ‘likely’, ‘very likely’, etc. To say something is ‘likely‘ the IPCC means it has a greater than 66% chance of happening.

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No Magic Bullet for Climate Change

Matt McGrath, Environment Correspondent for BBC News, posted a short piece entitled A ‘magic bullet’ to capture carbon dioxide?

Which was introduced as follows:

“CO2 is a powerful warming gas but there’s not a lot of it in the atmosphere – for every million particles of air, there are 410 of CO2.

The gas is helping to drive temperatures up around the world, but the comparatively low concentration means it is difficult to design efficient machines to remove it.

But a Canadian company, Carbon Engineering, believes it has found a solution.

Air is exposed to a chemical solution that concentrates the CO2. Further refinements mean the gas can be purified into a form that can be stored or utilised as a liquid fuel.”

The ‘magic bullet’ in the title is of course clickbait, because anyone who has spent any time looking at all the ways we need to reduce emissions or to draw down CO2 from the atmosphere will know that we need a wide range of solutions. There is no single ‘magic bullet’.

Not specifically commenting on this story, but in a related piece about so-called ‘Negative Emissions Technologies’ (NETs), Glen Peters highlights the scale of the challenge facing any type of NET, which aims to remove CO₂ from the atmosphere. 

To remove the excess CO₂, sufficient at least to keep below 2oC …

“essentially we need to build an industry that’s 3 to 4 times the size of the current oil & gas industry just to clean up our waste” (2nd April 2019)

The issue is one of both scale and timing. We need big interventions and we need them fast (or fast enough).

It would take time and considerable resources to scale up NETs, which are currently mostly still in their development phase, and so the immediate focus needs to be on other strategies including energy in the home, reduced consumption, rolling out renewables, changing diets, etc., for which the solutions are ready and waiting and just needed a massive push from Governments, industry and civil society.

Glen Peters stresses that the first priority is emissions reductions, rather than capture, although capture will be needed in due course either using natural methods, or technological ones, or some combination. 

There are big questions hanging over NETs such as BECCS (Bio-Energy with Carbon Capture and Storage), which would require between 1 and 5 ‘Indias’ of land area to make the contribution needed. The continuing fertility of soils to grow plants for BECCS and competition for land-use for agriculture, are just two of the concerns raised.

The technology highlighted in the BBC piece is DAC (Direct Air Capture) which could – powered by renewables – have great potential and avoids land-use competition, but is energy intensive. As with BECCS, DAC used in sequestration mode would still need to overcome hurdles, such as the geological ones related to safely burying CO₂ in perpetuity (my emphasis)

My concerns with Carbon Engineering’s proposed application of DAC – for fuel to be used in transport – are as follows.

Firstly, road, rail, and even shipping, are being electrified, making fuel redundant.  There is the competing hydrogen economy that would use fuel, but a non-carbon based one.  Either way, this will rapidly decarbonise these parts of transport. Since transport is overall 25% of global emissions currently, this is a highly significant ‘quick win’ for the planet (within 2 or at most 3 decades).

Commercial Aviation is 13% of transport’s carbon emissions, but is less easy to electrify – at the scale of airliners travelling long-distance – because of the current energy density and weight of batteries (this could change in the future, as Professor Clare Grey explained during an episode of The Life Scientific).

Aviation is therefore just above 3% of global emissions (13% of 25%) from all sectors (albeit a probably increasing percentage).  A development-stage technology being focused on just 3% of global emissions can hardly be framed as a ‘magic bullet’ to the climate crisis.

Secondly, in terms of Government financing, would we focus it on decarbonising road, or decarbonising aviation? I suggest the former not the latter if it came down to a choice.

DAC may be great to invest some money in, as development phase technology, but the big bucks needed immediately, to make a huge dent in emissions, are in areas such as road sector. 

It is not a binary choice of course, but the issue with financing is timing and scale again. The many solutions we forge ahead with now must meet the test that they are proven (not futurism/ delayism solutions like nuclear fusion), can be scaled fast, and will contribute significantly to carbon reductions while also helping to transition society in positive ways (as for example, the solutions in Project Drawdown offer, with numerous ‘co-benefits’)

Finally, it is worth stressing that the focus for Carbon Engineering (and hence the BBC report) is on the capture of carbon dioxide, to be converted into hydrocarbons as fuel, for burning. This effectively recycles atmospheric carbon. It neither adds to, nor takes away, carbon dioxide through this cycle.

This therefore makes zero change to CO₂ in the atmosphere. It might be whimsically called Carbon Capture and re-Emission technology (CCE)! 

So I think it was wrong of the BBC piece to give the impression that the goal was ‘Carbon Capture and Storage’ (CCS), whose aim is to draw down CO₂.

It is confusing to conflate CCE and CCS!

Especially when neither are magic bullets.

(c) Richard W. Erskine, 2019

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‘Possibilities Everywhere’ for more BP Greenwash

If you say “I am cutting down on smoking” and it turns out that from 7,300 cigarettes per year over the last 10 years you have managed to reduce your consumption by 25 cigarettes per year over the last 4 years and now are at 7,200 per year, then yes, it is true, you are cutting down.

But are you being honest?

In fact, it is fair to say that far from telling the truth you are in a sense lying or at least ‘dissembling’

screenshot 2019-01-23 at 11.15.32

That is what BP is doing with it’s latest massive ‘Possibilities Everywhere’ public relations and media advertising campaign, which was “jointly created by Ogilvy New York and Purple Strategies, with the films directed by Diego Contreras through Reset (US) and Academy (UK). The global media agency is Mindshare.”, as Campaign reports.

In a Youtube video on the initiative Lightsource BP is craftily suggesting it is seriously investing in solar energy, but don’t worry folks if the sun goes in, because we have plenty of gas as backup.

They want it both ways: claiming to be supporting renewables while continuing to push ahead with investments in fossil fuel discovery and production.

So let’s look at BP Annual Report and Form 20-F 2017 and what do we find. Let’s follow the money.

The on-going investments in upstream oil & gas development runs into many billions of dollars annually, which rather dwarfs the measly £300 million that Lightsource will be getting over three years by a factor of over 250.

This is not a serious push for renewables. 

If they were serious they would have actual renewables energy generation (arising from their ‘investments’) as one of their Key Performance Indicators (KPIs) in their Annual Report. They don’t because they don’t actually care, and they don’t expect their investors to care.

No, this is what BP cares about (from the same BP Annual Report) …

screenshot 2019-01-23 at 11.05.22

…. the value of their fossil fuel reserves. The more the better, because that has a huge influence on the share price.

In the Annual Report referenced above, BP states:

“Today, oil and gas account for almost 60% of all energy used. Even in a scenario that is consistent with the Paris goals of limiting warming to less than 2oC, oil and gas could provide around 40% of all energy used by 2040. So it’s essential that action is taken to reduce emissions from their production and use.

In a low carbon world, gas offers a much cleaner alternative to coal for power generation and a valuable back-up for renewables, for example when the sun and wind aren’t available. Gas also provides heat for industry and homes and fuel for trucks and ships.”

How do we decode this?

Well, what BP sees in a collapse of coal is a massive opportunity to grow oil & gas, but especially gas; they are not the only oil & gas company spotting the opportunity.

So they are not pushing energy storage for renewables, no, they are using intermittency as a messaging ploy to have gas as “a backup”.  So while 60% to 40% might look like a fall in profits, for BP’s gas investments it is a growth business, and less renewables means more growth in that gas business. So don’t get too big for your boots renewables – if we own you we can keep you in your place. Maybe you can rule when we have dug the last hole, but don’t expect that any time soon.

No amount of tinkering with emissions from production facilities or more efficient end-use consumption will avoid the conclusion that the “transition” they talk of must be a whole lot more urgent than the – dare I use the metaphor – glacial pace which BP are demonstrating.

Maybe BP should take seriously 3 key learning points:

  • Firstly, we have run out of time to keep playing these games. Your fossil fuel industry has to be placed on an aggressive de-growth plan, not the growth one you envisage, if you take seriously the implications of the IPCC’s 1.5C Special Report.
  • Secondly, far from your not-so-subtle digs at renewables, it is possible to construct an energy regime based on renewables (that does address intermittency issues); try reading reports like Zero Carbon Britain: Rethinking the Future from the Centre for Alternative Technology.
  • Thirdly, your investors will not thank you if you continue to ignore the serious risks from a ‘carbon bubble’. Claiming a value for BP assets based on unburnable fossil fuels will catch you out, sooner or later, and that your shareholders, pensioners and many others won’t thank you for your complacency.

Dissembling in respect of your commitment to the transition – which you intend to drag out for as long as possible it seems – will fool no one, and certainly not a public increasingly concerned about the impacts of global warming (and, by the way, also the impacts of plastics – another of your gifts to Mother Earth).

We are out of time.

By investing seriously and urgently in solutions that demonstrate a real commitment to the transition, and in planning to leave a whole lotta reserves in the ground, you can earn the trust of the public.

Change your KPIs to show you have read and understood the science on global warming.

Then you can build a PR campaign that demonstrates honesty and earns trust.

Until then, please, no more #BPGreenwash.

(c) Richard W. Erskine, 2019

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Veganism is an answer to the climate crisis, despite what the critics say

How the world feeds itself while at the same time becoming carbon neutral within a few decades (see Note 1), while at the same time protecting biodiversity and respecting other planetary boundaries, is a hugely complex issue. 

It is not helped by simplistic arguments on any side of the debate.

Food is much more complex than say, electricity generation or transport, because it brings together so many different interlocking threads, not least our different cultures and trading practices around the world; it cannot be glibly addressed through some technical silver bullet or indeed any single prescription.

Although it seems perfectly possible to have rewilding without conflating this with meat production for human consumption, Knepp Castle Estate clearly see these twinned in their overall vision for the Estate.

Knepp Castle Estate have done some wonderful work in their experiment to rewild the Estate’s farm and this has yielded some great results in promoting biodiversity on the farm. 

It is therefore disappointing that Isabelle Tree – who runs the Estate with her husband Sir Charles Burrell – decided that the way to counter what she believes are simplistic “exhortations” in favour of veganism is to use strawman arguments, which I will come to in a moment.

In her article “If you want to save the world, veganism isn’t the answer: Intensively farmed meat and dairy are a blight, but so are fields of soya and maize. There is another way” (Guardian, 25th August 2018), she offers a vision of meat produced on a rewilded farm as an alternative.

The article ends with a statement I think can be defended (even if I disagree with it):

“There’s no question we should all be eating far less meat, and calls for an end to high-carbon, polluting, unethical, intensive forms of grain-fed meat production are commendable. But if your concerns as a vegan are the environment, animal welfare and your own health, then it’s no longer possible to pretend that these are all met simply by giving up meat and dairy.”

The key words here are “simply by”, because of course, any diet begs a lot of questions on how food is produced, processed and transported. We all agree it is complicated.  We can all agree that a goat farmer in the Himalayas cannot simply adopt the practices of a farmer in England’s green pastures. We need to respect cultural and geographic diversity.

Except her last sentence does not address crop production methods, but simply asserts:

“Counterintuitive as it may seem, adding the occasional organic, pasture-fed steak to your diet could be the right way to square the circle.”

The problem is that to feed the UK or feed the world, we need to know what this means in quantitative terms, and there is really no indication of what a balanced omnivorous diet would look like or how to scale up the Knepp Castle Estate experiment, even for the UK.

Today, the reality of the impact – both in ecological and climate terms – of the meat industry is pretty terrifying, as the Friends Of the Earth laid bare in their 2008 report  “What’s feeding our food? – The environmental and social impacts of the livestock sector”.

We need alternatives, for sure, but any changes will take a long time to make a dent on a global scale. The world could simply follow the example of India with it relatively low level of meat consumption, but any proposed system must be able to scale effectively. 

Protein from livestock requires much greater land use, and also puts huge pressure on water resources, and as noted in the study ‘Redefining agricultural yields: from tonnes to people nourished per hectare’:

“… shifting the crop calories used for feed and other uses to direct human consumption could potentially feed an additional ∼4 billion people.”

Emily Cassidy et al, Environ. Res. Lett. 8 (2013) 034015

And if our goal is to address climate disruption as well as sustainable agriculture, the land will be in demand for other purposes: crops for human consumption; re-forestation; bio-energy crops; renewable energy assets; etc. 

Meat production whether it is intensively produced, or in a rewilded context, cannot wish away the basic fact that it is a relatively inefficient way of using land to produce calories.

The UK currently imports over 40% of its food, and on top of that imports soy and other crops for feed for livestock. Of the land we have in the UK, about 50% is given over to grassland for livestock, as illustrated in this Figure from the Zero Carbon Britain Report: Rethinking The Future:

screenshot 2019-01-07 at 09.19.53

The Centre for Alternative Technology’s alternative, set out in the same report, is aimed at getting the UK to zero carbon; balancing all the sectors that are involved, including food production, but recognising we need to fit everything required into the available land. They arrive at a radically different distribution of land-use:

screenshot 2019-01-07 at 09.20.06

In their scenario, livestock are not eliminated but are radically reduced.

What is most disappointing about Isabella Tree’s piece in the Guardian is that she feels the need to use Strawman Arguments to support her case (which immediately suggests it has some holes in it):

Strawman argument #1

“Rather than being seduced by exhortations to eat more products made from industrially grown soya, maize and grains, we should be encouraging sustainable forms of meat and dairy production based on traditional rotational systems, permanent pasture and conservation grazing.”  

My Response: Well, since most of those crops are grown for animal consumption, that is another reason to release that land to grow sustainable crops (in soil-carbon caring ways); for forests; for bio-energy crops; for human habitation; etc.  The net result of low intensive meat production is that we would need to massively reduce meat production.

Strawman argument #2

“In the vegan equation, by contrast, the carbon cost of ploughing is rarely considered … up to 70% of the carbon in our cultivated soils has been lost to the atmosphere”

My Response: Untrue. Why do we have the permaculture movement, low-till systems, etc.? And to stress again, the majority of the cropland in UK and US, for example, today is to feed livestock. If we want to improve soil carbon there are many ways of doing it.

I could go on.

She implies that the proposed method of farming will make a big impact on soil carbon sequestration, and there is no doubt that soil plays a hugely important role in carbon sequestration, but this is an area which is very complex. It is reassuring that the article does not make outlandish claims (such as those made by Savory, see Note 2), but again, there is a lack of any estimates as to the extent to which the proposed farming practices would mitigate increases in greenhouse gas emissions. Plausibility arguments won’t cut it I’m afraid. 

For those interested in exploring all the questions touched on so far and more besides – with the benefit of some science to back up claims –  they could not do better than look at a few of the excellent food research organisations in Oxford. 

Isabella Tree acknowledges that we need to reduce meat consumption. No doubt she would agree that the sky-rocketing consumption of meat in China and globally is unsustainable. Here is the current picture:

screenshot 2019-01-07 at 14.28.04

 And as Godfray et al. state in the paper from which I took this Figure:

“It is difficult to envisage how the world could supply a population of 10 billion or more people with the quantity of meat currently consumed in most high-income countries without substantial negative effects on environmental sustainability. “

Godfray et al., Science 361, 243 (2018), 20th July 2018

Yes, it is much more complicated than simply choosing one’s diet, and we must all take care to consider the processes and pathways by which we get our food and how land is used – whether we eat meat or not. 

But for many, veganism remains an increasingly obvious option to make an immediate dent in one’s carbon footprint, and it remains a perfectly justifiable choice, whether from an environmental, ethical or scientific standpoint. 

It is by no means clear that even as a portion of our weekly diet, rewilded meat will be the solution to the world’s environmental and sustainability challenges, or at least on the timescales required. Veganism can make an immediate impact.

In fact, without a whole lot more vegans on this planet, it is difficult to see how those who want to remain meat eaters can carry on doing so with a clear conscience, given the current (as opposed to, wished for) farming practices.

In the future, meat eaters may have to pay a lot more to eat meat and even then give a big nod of thanks to vegans for making a space for them to do so.

If Isabella Tree’s article was entitled “If you want to save the world, veganism isn’t the whole answer: Intensively farmed meat and dairy are a blight along with the fields of soya and maize they depend on. But there is a case for low levels of meat consumption.” …          it would have been less catchy but at least defensible.

Knepp Castle Estate are doing great work showing how to promote biodiversity on their farm, but as a model for feeding the world and preventing dangerous climate disruption, by 2050 or earlier … they have failed to make a convincing case that they have a credible plan.

(c) Richard W. Erskine, 2019


Note 1

On our current emissions trajectory, the world “is likely to reach 1.5C between 2030 and 2052”. If we are to avoid a global mean surface temperature rise of 1.5C, net global CO2 emissions need to fall by about 45% from 2010 levels by 2030 and reach “net zero” by around 2050.  See Carbon Brief’s ‘In-depth Q&A: The IPCC’s special report on climate change at 1.5C’ for more details. The IPCC’s 1.5C report made it clear that the difference between a 1.5C world and a 2C world was very significant, and so every year counts. The sooner we can peak the atmospheric concentration of greenhouse gases (especially CO2, being long-lived) in the atmosphere, the better.

Note 2

Savory suggested that over a period of 3 or 4 decades you can draw down the whole of the anthropogenic amount that has accumulated (which is nearly 2000 Gigatonnes of carbon dioxide), whereas a realistic assessment (e.g. ) is suggesting a figure of 14 gigatonnes of carbon dioxide (more than 100 times less) is possible in the 2020-2050 timeframe.

FCRN explored Savory’s methods and claims, and find that despite decades of trying, he has not demonstrated that his methods work.  Savory’s case is very weak, and he ends up (in his exchanges with FCRN) almost discounting science; saying his methods are not susceptible to scientific investigations. 

In an attempt to find some science to back himself up, Savory referenced Gattinger, but that doesn’t hold up either. Track down Gattinger et al’s work  and it reveals that soil organic carbon could (on average, with a large spread) capture 0.4GtC/year (nowhere near annual anthropogenic emissions of 10GtC), and if it cannot keep up with annual emissions, forget soaking up the many decades of historical emissions (the 50% of these that persists for a very long time in the atmosphere), which some are claiming is possible.

I recommend Dr Tara Garnett‘s Blog-post: ‘Why eating grass-fed beef isn’t going to help fight climate change’, 3rd October 2017 – and if you need more, read the full paper referenced in the blog.


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On the Nth Day of Christmas …

We had a seasonal pub lunch with neighbours, and my christmas cracker included the question:

“How many gifts would you have if you received all the gifts in the song ‘The Twelve Days of Christmas’?”

The song indicates the following gifts I will receive on each day:

on 1st day I’ll receive, a partridge in a pear tree;

on 2nd day, 2 turtle doves and a partidge in a pear tree;

on 3rd day, 3 French hens, 2 turtle doves and a partidge in a pear tree;


So, by the twelth day I will have received a total of:

12 x 1 partridges (each in a pear tree);

11 x 2 turtle doves;

10 x 3 French hens;

… etc; (until we get to)

1 x 12 drummers drumming.

So, the total number of gifts is:

(12×1) + (11×2) + (10×3) + … + (1×12)

which my abstemious wife very rapidly computed is 364 gifts.

By which time and after a few glasses of wine, I was of course wanting a more general result, so I declared:

“What about the number of gifts on the Nth day of Christmas?”

My wife mumbled “here we go!”, and by then my pen and paper napkin were at the ready …

Assuming the general gifts were denoted g1, g2, g3, …, gN, then we’d end up with…

N x 1 of gift g1

(N-1) x 2 of gift g2

(N-3) x 3 of gift g3

… etc. until

1 x N of gift gN

Let’s call the total number of gifts arrived at as G(N). So as an example, we already know that G(12) = 364

In mathematical notation I can write this in a different way (see Note 1), and solve the equation to show that …

G(N) = (1/6) * N * (N+1) * (N+2)

Testing this equation for case of N=12 I get

G(12) = (1/6) * 12 * 13 *14

           = 2 *13 * 14

           = 364

Job done!

When I got home I wondered if there was a geometrical way of deriving this result, rather like the trick that Gauss used as a young boy when the teacher asked the class to add the whole numbers from 1 to 100 (see Note 2).

I rather like the visual proof which I can show for N=4 as:


which generally (for N rather than 4), and expressed algebrailly, can be expressed as

N∑[i] = (N2 – N)/2  + N

= (N2 /2) – N/2 + N

= (N2 /2) + N/2

= (1/2) * N * (N+1)

My question to myself was can we do a similar visual trick with the Nth Days of Christmas sum? (I say we, but without the genius Gauss to assist me!).

We have to go three dimensional now to build a picture of the number. The child’s blocks I could find were too few in number and we don’t have sugar cubes, but we do have veggie stock cubes! So, I created the following …

IMG_4738 3.JPG

The left hand portion represents 3×1 + 2×2 + 1×3 which is G(3)

The same number of blocks is in the right portion (in mirror image).

In the middle I have added 1+2+3+4 which is the familiar 4∑[i]

Put these all together and the picture is as follows:

IMG_4739 3.JPG

which is clearly 12+22+32+42  which is the familiar 4∑[i2]

That’s a nice pictorial solution of a kind.

So in algebraic terms that gives

2 G(3) + 4∑[i]  =  4∑[i2]

This gives me an algebraic solution that is not any simpler than the original solution I made on the napkin. The stock cubes give me:

G(N-1)  =  (1/2) * ( N∑[i2] – N∑[i] )

which can be solved (Note 3) to give

G(N) = (1/6) * N * (N+1) * (N+2)

as before.

However, I felt I had failed in my quest to avoid algebra or at least a much simpler algebraic resolution. Ultimately I couldn’t find one, but the visualization is at least a great way to play with the number relationships.

At least I will be very quick with the answer if ever I am asked

“How many gifts would you have if you received all the gifts in the general song ‘The N Days of Christmas’?”

“Oh, that’s easy, it one sixth of N, times N plus one, times N plus two.”


Richard W. Erskine, 30th December 2018


Note 1

G(N) can be written as the following sum:

G(N) = ∑ [(N – i + 1) * ( i )]

where N∑[] is shorthand for “sum of expression […] for i ranging from 1 to N”

Expanding the expression, I get

G(N) = ( (N+1) * N∑[i] )  –   N∑[i2]

Now, there are well known results that give us, firstly

N∑[i] = (1/2) * N * (N+1)

and secondly,

N∑[i2] = (1/6) * N * (N+1) * (2N + 1)

So, combining these I get,

G(N) = ((N+1) * (1/2) * N * (N+1) )   –  ((1/6) * N * (N+1) * (2N + 1))

Taking out a common factor (1/6) * N * (N+1), this becomes

G(N) = (1/6) * N * (N+1) * { 3*(N+1) – (2N + 1) }

Simplifying { 3*(N+1) – (2N + 1) } I get {N+2}, so

G(N) = (1/6) * N * (N+1) * (N+2)

Note 2

Gauss as a boy spotted a short-cut, which can be seen in the following picture:


The sum 1+2+3+4 is represented by the shaded blocks, and the unshaded blocks are also the same sum in reverse order. So, we can see

1+2+3+4 = (1/2) * 4 * (4+1) = 2 * 5 = 10

and in general

N∑[i] = (1/2) * N * (N+1)


Note 3

G(N-1) = (1/2) * ( N∑[i2] – N∑[i] )

= (1/2) * { { (1/6) * N * (N+1) * (2N + 1) } – {(1/2) * N * (N+1) } }

= (1/2) * (1/6) * N * (N+1) * { (2N + 1)  –  3 }

= (1/2) * (1/6) * N * (N+1) * { 2N  –  2 }

= (1/6) * N * (N+1) * { N – 1 }


G(N) = (1/6) * (N+1) * (N+2)  * N

or, rearranging

G(N) = (1/6) * N * (N+1) * (N+2)

as before.


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