Category Archives: Climate Science

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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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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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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Communicating Key Figures from IPCC Reports to a Wider Public

If you were to think about ranking the most important Figures from the IPCC Fifth Assessment Report, I would not be surprised if the following one (SPM.10) did not emerge as a strong candidate for the number one slot:

IPCC AR5 Figure SPM.10

This is how the Figure appears in the main report, on page 28 (in the Summary for Policymakers) of The Physical Basis Report (see References: IPCC, 2013). The Synthesis Report includes a similar figure with additional annotations.

Many have used it in talks because of its fundamental importance (for example, Sir David King in his Walker Institute Annual Lecture (10th June 2015), ahead of COP21 in Paris). I have followed this lead, and am sure that I am not alone.

This Figure shows an approximately linear1 relationship between the cumulative carbon dioxide we emit2, and the rise in global average surface temperature3 up to 2100. It was crucial to discussions on carbon budgets held in Paris and the goal of stabilising the climate.

I am not proposing animating this Figure in the way discussed in my previous essay, but I do think its importance warrants additional attention to get it out there to a wider audience (beyond the usual climate geeks!).

So my question is:

“Does it warrant some kind of pedagogic treatment for a general audience (and dare I say, for policy-makers who may themselves struggle with the density of information conveyed)?”

My answer is yes, and I believe that the IPCC, as guardians of the integrity of the report findings, are best placed to lead such an effort, albeit supported by skills to support the science communications.

The IPCC should not leave it to bloggers and other commentators to furnish such content, as key Figures such as this are fundamental to the report’s findings, and need to be as widely understood as possible.

While I am conscious of Tufte’s wariness regarding Powerpoint, I think that the ‘build’ technique – when used well – can be extremely useful in unfolding the information, in biteable chunks. This is what I have tried to do with the above Figure in a recent talk. I thought I would share my draft attempt.

It can obviously do with more work, and the annotations represent my emphasis and use of  language4. Nevertheless, I believe I was able to truthfully convey the key information from the original IPCC Figure more successfully than I have before; taking the audience with me, rather than scaring them off.

So here goes, taken from a segment of my talk … my narrative, to accompany the ‘builds’, is in italics …

Where are we now?

“There is a key question: what is the relationship between the peak atmospheric concentration and the level of warming, compared to a late 19th century baseline, that will result, by the end of the 21st century?”

“Let’s start with seeing where we are now, which is marked by a X in the Figure below.” 

Unpacking SYR2.3 - Build 1

“Our cumulative man-made emissions of carbon dioxide (CO2) have to date been nearly 2000 billion tonnes (top scale above)”

“After noting that 50% of this remains in the atmosphere, this has given rise to an increase in the atmospheric concentration from its long-standing pre-industrial value of 280 parts per million to it current value which is now about 400 parts per million (bottom scale above).”

“This in turn has led to an increase in averaged global surface temperature of  1oC above the baseline of 1861 to 1880 (vertical scale above).”

Where might we be in 2100?

“As we add additional carbon dioxide, the temperature will rise broadly in proportion to the increased concentration in the atmosphere. There is some uncertainty between “best case” and “worst case” margins of error (shown by the dashed lines).” 

Unpacking SYR2.3 - Build 2

“By the end of the century, depending on how much we emit and allowing for uncertainties, we can end up anywhere within the grey area shown here. The question marks (“?”) illustrate where we might be by 2100.”

Can we stay below 2C?

“The most optimistic scenario included in the IPCC’s Fifth Assessment Report (AR5) was based on the assumption of a rapid reduction in emissions, and a growing role for the artificial capture of carbon dioxide from the atmosphere (using a technology called BECCS).” 

Unpacking SYR2.3 - Build 3

“This optimistic scenario would meet the target agreed by the nations in Paris, which is to limit the temperature rise to 2oC.”

“We effectively have a ‘carbon budget’; an amount of fossil fuels that can be burned and for us to stay below 2oC”. 

“The longer we delay dramatically reducing emissions, the faster the drop would need to be in our emissions later, as we approach the end of the ‘carbon budget’.” 

“Some argue that we are already beyond the point where we can realistically move fast enough to make this transition.” 

“Generally, experts agree it is extremely challenging, but still not impossible.”

Where will we be in 2100?  – Paris Commitments

“The nationally determined contributions (or NDCs) – the amounts by which carbon dioxide emissions will fall – that the parties to the Paris Agreement put forward have been totted up and they would, if implemented fully, bring us to a temperature rise of between 2.5 and 3.5 oC (and an atmospheric concentration about twice that of pre-industrial levels).”

Unpacking SYR2.3 - Build 4

 “Now, the nations are committed to increase their ‘ambition’, so we expect that NDCs should get better, but it is deeply concerning that at present, the nations’ current targets are (1) not keeping us unambiguously clear of catastrophe, and (2) struggling to be met. More ambition, and crucially more achievement, is urgent.”

“I have indicated the orange scenarios as “globally severe”, but for many regions “catastrophic” (but some, for example, Xu and Ramanathan5, would use the term “Catastrophic” for any warming over 3oC, and “Unknown” for warming above 5oC). The IPCC are much more conservative in the language they use.”

Where will we be in 2100? – Business As Usual Scenario

“The so-called ‘business as usual’ scenario represents on-going use of fossil fuels, continuing to meet the majority of our energy needs, in a world with an increasing population and increasing GDP per capita, and consequently a continuing growth in CO2 emissions.”

Unpacking SYR2.3 - Build 5

”This takes global warming to an exceptionally bad place, with a (globally averaged) temperature rise of between 4 and 6 oC; where atmospheric concentrations will have risen to between 2.5 and 3 times the pre-industrial levels.”

“The red indicates that this is globally catastrophic.”

“If we go above 5oC warming we move, according to Xu and Ramanathan,  from a “catastrophic” regime to an “unknown” one. I have not tried to indicate this extended vocabulary on the diagram, but what is clear is that the ‘business as usual’ scenario is really not an option, if we are paying attention to what the science is telling us.”

That’s it. My draft attempt to convey the substance and importance of Figure SPM.10, which I have tried to do faithfully; albeit adding the adjectives “optimistic” etc. to characterise the scenarios.

I am sure the IPCC could do a much better job than me at providing a more accessible presentation of Figure SPM.10 and indeed, a number of high ranking Figures from their reports, that deserve and need a broader audience.

© Richard W. Erskine


  1. The linearity of this relationship was originally discussed in Myles Allen et al (2009), and this and other work has been incorporated in the IPCC reports. Also see Technical Note A below.
  1. About half of which remains in the atmosphere, for a very long time
  1. Eventually, after the planet reaches a new equilibrium, a long time in the future. Also see Technical Note B below.
  1. There are different opinions are what language to use – ‘dangerous’, ‘catastrophic’, etc. – and at what levels of warming to apply this language. The IPCC is conservative in its use of language, as is customary in the scientific literature. Some would argue that in wanting to avoid the charge of being alarmist, it is in danger of obscuring the seriousness of the risks faced. In my graphics I have tried to remain reasonably conservative in the use of language, because I believe things are serious enough; even when a conservative approach is taken.
  1. Now, Elizabeth Kolbert has written in the New Yorker:

In a recent paper in the Proceedings of the National Academy of Sciences, two climate scientists—Yangyang Xu, of Texas A. & M., and Veerabhadran Ramanathan, of the Scripps Institution of Oceanography—proposed that warming greater than three degrees Celsius be designated as “catastrophic” and warming greater than five degrees as “unknown??” The “unknown??” designation, they wrote, comes “with the understanding that changes of this magnitude, not experienced in the last 20+ million years, pose existential threats to a majority of the population.”


  • IPCC, 2013: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovern- mental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1535 pp.
  • IPCC, 2001: Climate Change 2001: The Scientific Basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change [Houghton, J.T., Y. Ding, D.J. Griggs, M. Noguer, P.J. van der Linden, X. Dai, K. Maskell, and C.A. Johnson (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 881pp.
  • Myles Allen at al (2009), “Warming caused by cumulative carbon emissions towards the trillionth tonne”,Nature 458, 1163-1166
  • Kirsten Zickfeld et al (2016), “On the proportionality between global temperature change and cumulative CO2 emissions during periods of net negative CO2 emissions”, Environ. Res. Lett. 11 055006

Technical Notes

A. Logarithmic relationship?

For those who know about the logarithmic relationship between added CO2 concentration and the ‘radiative forcing’ (giving rise to warming) – and many well meaning contrarians seem to take succour from this fact – the linear relationship in this figure may at first sight seem surprising.

The reason for the linearity is nicely explained by Marcin Popkiewicz in his piece “If growth of COconcentration causes only logarithmic temperature increase – why worry?”

The relative warming (between one level of emissions and another) is related to the ratio of this logarithmic function, and that is approximately linear over the concentration range of interest.

In any case, it is worth noting that CO2 concentrations have been increasing exponentially, and a logarithm of an exponential function is a linear function.

There is on-going work on wider questions. For example, to what extent ‘negative emissions technology’ can counteract warming that is in the pipeline?

Kirsten Zickfield et al (2016), is one such paper, “…[suggests that] positive CO2 emissions are more effective at warming than negative emissions are at subsequently cooling”. So we need to be very careful in assuming we can reverse warming that is in the pipeline.

B. Transient Climate Response and Additional Warming Commitment

The ‘Transient Climate Response’ (TCR) reflects the warming that results when CO2 is added at 1% per year, which for a doubling of the concentration takes 70 years. This is illustrated quite well in a figure from a previous report (Reference: IPCC, 2001):

TAR Figure 9.1

The warming that results from this additional concentration of CO2 occurs over the same time frame. However, this does not include all the the warming that will eventually result because the earth system (principally the oceans and atmosphere) will take a long time to reach a new equilibrium where all the flows of energy are brought back into a (new) balance. This will take at least 200 years (for lower emission scenarios) or much longer for higher emission levels.  This additional warming commitment must be added to the TCR. However, the TCR nevertheless does represent perhaps 70% of the overall warming, and remains a useful measure when discussing policy options over the 21st Century.

This discussion excludes more uncertain and much longer term feedbacks involving, for example, changes to the polar ice sheets (and consequentially, the Earth’s albedo), release of methane from northern latitudes or methane clathrates from the oceans. These are not part of the ‘additional warming commitment’, even in the IPCC 2013 report, as they are considered too speculative and uncertain to be quantified.

. . o O o . .

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Animating IPCC Climate Data

The IPCC (Intergovernmental Panel on Climate Change) is exploring ways to improve the communication of its findings, particularly to a more general  audience. They are not alone in having identified a need to think again about clear ‘science communications’. For example, the EU’s HELIX project (High-End Climate Impacts and Extremes), produced some guidelines a while ago on better use of language and diagrams.

Coming out of the HELIX project, and through a series of workshops, a collaboration with the Tyndall Centre and Climate Outreach, has produced a comprehensive guide (Guide With Practical Exercises to Train Researchers In the Science of  Climate Change Communication)

The idea is not to say ‘communicate like THIS’ but more to share good practice amongst scientists and to ensure all scientists are aware of the communication issues, and then to address them.

Much of this guidance concerns the ‘soft’ aspects of communication: how the communicator views themself; understanding the audience; building trust; coping with uncertainty; etc.

Some of this reflects ideas that are useful not just to scientific communication, but almost any technical presentation in any sector, but that does not diminish its importance.

This has now been distilled into a Communications Handbook for IPCC Scientists; not an official publication of the IPCC but a contribution to the conversation on how to improve communications.

I want to take a slightly different tack, which is not a response to the handbook per se, but covers a complementary issue.

In many years of being involved in presenting complex material (in my case, in enterprise information management) to audiences unfamiliar with the subject at hand, I have often been aware of the communication potential but also risks of diagrams. They say that a picture is worth a thousand words, but this is not true if you need a thousand words to explain the picture!

The unwritten rules related to the visual syntax and semantics of diagrams is a fascinating topic, and one which many – and most notably Edward Tufte –  have explored. In chapter 2 of his insightful and beautiful book Visual Explanations, Tufte argues:

“When we reason about quantityative evidence, certain methods for displaying and analysing data are better than others. Superior methods are more likely to produce truthful, credible, and precise findings. The difference between an excellent analysis and a faulty one can sometimes have momentous consequences”

He then describes how data can be used and abused. He illustrates this with two examples: the 1854 Cholera epidemic in London and the 1986 Challenger space shuttle disaster.

Tufte has been highly critical of the over reliance on Powerpoint for technical reporting (not just presentations) in NASA, because the form of the content degrades the narrative that should have been an essential part of any report (with or without pictures). Bulletized data can destroy context, clarity and meaning.

There could be no more ‘momentous consequences’ than those that arise from man-made global warming, and therefore, there could hardly be a more important case where a Tuftian eye, if I may call it that, needs to be brought to bear on how the information is described and visualised.

The IPCC, and the underlying science on which it relies, is arguably the greatest scientific collaboration ever undertaken, and rightly recognised with a Nobel Prize. It includes a level of interdisciplinary cooperation that is frankly awe-inspiring; unique in its scope and depth.

It is not surprising therefore that it has led to very large and dense reports, covering the many areas that are unavoidably involved: the cryosphere, sea-level rise, crops, extreme weather, species migration, etc.. It might seem difficult to condense this material without loss of important information. For example, Volume 1 of the IPCC Fifth Assessment Report, which covered the Physical Basis of Climate Change, was over 1500 pages long.

Nevertheless, the IPCC endeavours to help policy-makers by providing them with summaries and also a synthesis report, to provide the essential underlying knowledge that policy-makers need to inform their discussions on actions in response to the science.

However, in its summary reports the IPCC will often reuse key diagrams, taken from the full reports. There are good reasons for this, because the IPCC is trying to maintain mutual consistency between different products covering the same findings at different levels of detail.

This exercise is fraught with risks of over-simplification or misrepresentation of the main report’s findings, and this might limit the degree to which the IPCC can become ‘creative’ with compelling visuals that ‘simplify’ the original diagrams. Remember too that these reports need to be agreed by reviewers from national representatives, and the language will often seem to combine the cautiousness of a scientist with the dryness of a lawyer.

So yes, it can be problematic to use artistic flair to improve the comprehensibility of the findings, but risk losing the nuance and caution that is a hallmark of science. The countervailing risk is that people do not really ‘get it’; and do not appreciate what they are seeing.

We have seen with the Challenger reports, that people did not appreciate the issue with the O rings, especially when key facts were buried in 5 levels of indented bullet points in a tiny font, for example or, hidden in plain sight, in a figure so complex that the key findings are lost in a fog of complexity.

That is why any attempt to improve the summaries for policy makers and the general public must continue to involve those who are responsible for the overall integrity and consistency of the different products, not simply hived off to a separate group of ‘creatives’ who would lack knowledge and insight of the nuance that needs to be respected.  But those complementary skills – data visualizers, graphics artists, and others – need to be included in this effort to improve science communications. There is also a need for those able to critically evaluate the pedagogic value of the output (along the lines of Tufte), to ensure they really inform, and do not confuse.

Some individuals have taken to social media to present their own examples of how to present information, which often employs animation (something that is clearly not possible for the printed page, or its digital analogue, a PDF document). Perhaps the most well known example to date was Professor Ed Hawkin’s spiral picture showing the increase in global mean surface temperature:


This animation went viral, and was even featured as part of the Rio Olympics Opening Ceremony. This and other spiral animations can be found at the Climate Lab Book site.

There are now a number of other great producers of animations. Here follows a few examples.

Here, Kevin Pluck (@kevpluck) illustrates the link between the rising carbon dioxide levels and the rising mean surface temperature, since 1958 (the year when direct and continuous measurements of carbon dioxide were pioneered by Keeling)

Kevin Pluck has many other animations which are informative, particularly in relation to sea ice.

Another example, from Antti Lipponen (@anttilip), visualises the increase in surface warming from 1900 to 2017, by country, grouped according to continent. We see the increasing length/redness of the radial bars, showing an overall warming trend, but at different rates according to region and country.

A final example along the same lines is from John Kennedy (@micefearboggis), which is slightly more elaborate but rich in interesting information. It shows temperature changes over the years, at different latitudes, for both ocean (left side) and land (right side). The longer/redder the bar the higher the increase in temperature at that location, relative to the temperature baseline at that location (which scientists call the ‘anomaly’). This is why we see the greatest warming in the Arctic, as it is warming proportionally faster than the rest of the planet; this is one of the big takeaways from this animation.

These examples of animation are clearly not dumbing down the data, far from it. They  improve the chances of the general public engaging with the data. This kind of animation of the data provides an entry point for those wanting to learn more. They can then move onto a narrative treatment, placing the animation in context, confident that they have grasped the essential information.

If the IPCC restricts itself to static media (i.e. PDF files), it will miss many opportunities to enliven the data in the ways illustrated above that reveal the essential knowledge that needs to be communicated.

(c) Richard W. Erskine, 2018


Filed under Climate Science, Essay, Science Communications

Matt Ridley shares his ignorance of climate science (again)

Ridley trots out a combination of long-refuted myths that are much loved by contrarians; bad or crank science; or misunderstandings as to the current state of knowledge. In the absence of a Climate Feedback dissection of Ridley’s latest opinion piece, here is my response to some of his nonsense …

Here are five statements he makes that I will refute in turn.

1. He says: Forty-five years ago a run of cold winters caused a “global cooling” scare.

I say:

Stop repeating this myth Matt! A few articles in popular magazines in the 70s speculated about an impending ice age, and so according to dissemblers like Ridley, they state or imply that this was the scientific consensus at the time (snarky message: silly scientists can’t make your mind up). This is nonsense, but so popular amongst contrarians it is repeated frequently to this day.

If you want to know what scientists were really thinking and publishing in scientific papers read “The Myth of the 1970s Global Cooling Scientific Consensus”, by Thomas Peterson at al (2008), American Meteorological Society.

Warming, not cooling was the greater concern. It is astonishing that Ridley and others continue to repeat this myth. Has he really been unable – in the ten years since it was published – to read this oft cited article and so disabuse himself of the myth? Or does he deliberately repeat it because he thinks his readers are too lazy or too dumb to check the facts? How arrogant would that be?

2. He says: Valentina Zharkova of Northumbria University has suggested that a quiescent sun presages another Little Ice Age like that of 1300-1850. I’m not persuaded. Yet the argument that the world is slowly slipping back into a proper ice age after 10,000 years of balmy warmth is in essence true.

I say:

Oh dear, he cites the work of Zharkova, saying he is not persuaded, but then talks of ‘slowly slipping into a proper ice age’. A curious non sequitur. While we are on Zharkova, her work suffered from being poorly communicated.

And quantitatively, her work has no relevance to the current global warming we are observing. The solar minimum might create a -0.3C contribution over a limited period, but that would hardly put a dent in the +0.2C per decade rate of warming.

But, let’s return to the ice age cycle. What Ridley obdurately refuses to acknowledge is that the current warming is occurring due to less than 200 years of man-made changes to the Earth’s atmosphere, raising CO2 to levels not seen for nearly 1 million years (equal to 10 ice age cycles), is raising the global mean surface temperature at an unprecedented rate.

Therefore, talking about the long slow descent over thousands of years into an ice age that ought to be happening (based on the prior cycles), is frankly bizarre, especially given that the man-made warming is now very likely to delay a future ice age. As the a paper by Ganopolski et al, Nature (2016) has estimated:

“Additionally, our analysis suggests that even in the absence of human perturbations no substantial build-up of ice sheets would occur within the next several thousand years and that the current interglacial would probably last for another 50,000 years. However, moderate anthropogenic cumulative CO2 emissions of 1,000 to 1,500 gigatonnes of carbon will postpone the next glacial inception by at least 100,000 years.”

And why stop there, Matt? Our expanding sun will boil away the oceans in a billion years time, so why worry about Brexit; and don’t get me started on the heat death of the universe. It’s hopeless, so we might as well have a great hedonistic time and go to hell in a handcart! Ridiculous, yes, but no less so than Ridley conflating current man-made global warming with a far, far off ice age, that recedes with every year we fail to address man-made emissions of CO2.

3. He says: Well, not so fast. Inconveniently, the correlation implies causation the wrong way round: at the end of an interglacial, such as the Eemian period, over 100,000 years ago, carbon dioxide levels remain high for many thousands of years while temperature fell steadily. Eventually CO2 followed temperature downward.

I say:

The ice ages have indeed been a focus of study since Louis Agassiz coined the term in 1837, and there have been many twists and turns in our understanding of them even up to the present day, but Ridley’s over-simplification shows his ignorance of the evolution of this understanding.

The Milankovitch Cycles are key triggers for entering, an ice age (and indeed, leaving it), but the changes in atmospheric concentrations of carbon dioxide drives the cooling (entering) and warming (leaving) of an ice age, something that was finally accepted by the science community following Hays et al’s 1976 seminal paper (Variations in the Earth’s orbit: Pacemake of the ice ages) , over 50 years since Milankovitch first did his work.

But the ice core data that Ridley refers to confirms that carbon dioxide is the driver, or ‘control knob’, as Professor Richard Alley explains it; and if you need a very readable and scientifically literate history of our understanding of the ice cores and what they are telling us, his book “The Two-Mile Time Machine: Ice Cores, Abrupt Climate Change, and Our Future” is a peerless, and unputdownable introduction.

Professor Alley offers an analogy. Suppose you take out a small loan, but then after this interest is added, and keeps being added, so that after some years you owe a lot of money. Was it the small loan, or the interest rate that created the large debt? You might say both, but it is certainly ridiculous to say the the interest rate is unimportant because the small loan came first.

But despite its complexity, and despite the fact that the so-called ‘lag’ does not refute the dominant role of CO2, scientists are interested in explaining such details and have indeed studied the ‘lag’. In 2012, Shakun and others published a paper doing just that “Global warming preceded by increasing carbon dioxide concentrations during the last deglaciation”(Jeremy D. Shakun et al, Nature 484, 49–54, 5 April 2012). Since you may struggle to see a copy of this paywalled paper, a plain-English summary is available.

Those who read headlines and not contents – like the US Politician Joe Barton – might think this paper is challenging the dominant role of CO2, but the paper does not say that.  This paper showed that some warming occurred prior to increased CO2, but this is explained as an interaction between Northern and Southern hemispheres, following the Milankovitch original ‘forcing’.

The role of the oceans is crucial in fully explaining the temperature record, and can add significant delays in reaching a new equilibrium. There are interactions between the oceans in Northern and Southern hemispheres that are implicated in some abrupt climate change events (e.g.  “North Atlantic ocean circulation and abrupt climate change during the last glaciation”, L. G. Henry et al, Science,  29 July 2016 • Vol. 353 Issue 6298).

4. He says: Here is an essay by Willis Eschenbach discussing this issue. He comes to five conclusions as to why CO2 cannot be the main driver

I say:

So Ridley quotes someone with little or no scientific credibility who has managed to publish in Energy & Environment. Its editor Dr Sonja Boehmer-Christiansen admitted that she was quite partisan in seeking to publish ‘sceptical’ articles (which actually means, contrarian articles), as discussed here.

Yet, Ridley extensively quotes this low grade material, but could have chosen from hundreds of credible experts in the field of climate science. If he’d prefer ‘the’ textbook that will take him through all the fundamentals that he seems to struggle to understand, he could try Raymond Pierrehumbert’s seminal textbook “Principles of Planetary Climate”. But no. He chooses Eschenbach, with a BA in Psychology.

Ridley used to put up the appearance of interest in a rational discourse, albeit flying in the face of the science. That mask has now fully and finally dropped, as he is now channeling crank science. This is risible.

5. He says: The Antarctic ice cores, going back 800,000 years, then revealed that there were some great summers when the Milankovich wobbles should have produced an interglacial warming, but did not. To explain these “missing interglacials”, a recent paper in Geoscience Frontiers by Ralph Ellis and Michael Palmer argues we need carbon dioxide back on the stage, not as a greenhouse gas but as plant food.

I say:

The paper is 19 pages long, which is unusual in today’s literature. The case made is intriguing but not convincing, but I leave it to the experts to properly critique it. It is taking a complex system, where for example, we know that large movements of heat in the ocean have played a key role in variability, and tries to infer (explaining interglacials) that dust is the primary driver, while discounting the role of CO2 as a greenhouse gas.

The paper curiously does not cite the seminal paper by Hays et al (1976), yet cites a paper by Willis Eschenbach published in Energy & Environment (which I mentioned earlier). All this raised concerns in my mind about this paper.

Extraordinary claims require extraordinary evidence and scientific dialogue, and it is really too early to claim that this paper is something or nothing; even if that doesn’t mean waiting the 50 odd years that Milankovitch’s work had to endure, before it was widely accepted. Good science is slow, conservative, and rigorous, and the emergence of a consilience on the science of our climate has taken a very long time, as I explored in a previous essay.

Ralph Ellis on his website (which shows that his primary interest is the history of the life and times of Jesus) states:

“Ralph has made a detour into palaeoclimatology, resulting in a peer-review science paper on the causes of ice ages”, and after summarising the paper says,

“So the alarmists were right about CO2 being a vital forcing agent in ice age modulation – just not in the way they thought”.

So was this paper an attempt to clarify what was happening during the ice ages, or a contrivance, to take a pot shot at carbon dioxide’s influence on our contemporary climate change?

The co-author, Michael Palmer, is a biochemist, with no obvious background in climate science and provided “a little help” on the paper according to his website.

But on a blog post comment he offers a rather dubious extrapolation from the paper:

“The irony is that, if we should succeed in keeping the CO2 levels high through the next glacial maximum, we would remove the mechanism that would trigger the glacial termination, and we might end up (extreme scenario, of course) another Snowball Earth.”,

They both felt unembarrassed participating in comments on the denialist blog site WUWT. Quite the opposite, they gleefully exchanged messages with a growing band of breathless devotees.

But even if my concerns about the apparent bias and amateurism of this paper were allayed, the conclusion (which Ridley and Ellis clearly hold to) that the current increases in carbon dioxide is nothing to be concerned with, does not follow from this paper. It is a non sequitur.

If I discovered a strange behavour like, say, the Coriolis force way back when, the first conclusion would not be to throw out Newtonian mechanics.

The physics of CO2 is clear. How the greenhouse effect works is clear, including for the conditions that apply on Earth, with all remaining objections resolved since no later than the 1960s.

We have a clear idea of the warming effect of increased CO2 in the atmosphere including short term feedbacks, and we are getting an increasingly clear picture of how the Earth system as a whole will respond, including longer term feedbacks.  There is much still to learn of course, but nothing that is likely to require jettisoning fundamental physics.

The recent excellent timeline published by Carbon Brief showing the history of the climate models, illustrates the long slow process of developing these models, based on all the relevant fundamental science.

This history has shown how different elements have been included in the models as the computing power has increased – general circulation, ocean circulation, clouds, aerosols, carbon cycle, black carbon.

I think it is really because Ridley still doesn’t understand how an increase from 0.03% to 0.04% over 150 years or so, in the atmospheric concentration of CO2, is something to be concerned about (or as I state it in talks, a 33% rise in the principal greenhouse gas; which avoids Ridley’s deliberately misleading formulation).

He denies that he denies the Greenhouse Effect, but every time he writes, he reveals that really, deep down, he still doesn’t get it. To be as generous as I can to him, he may suffer from a perpetual state of incredulity (a common condition I have written about before).


Matt Ridley in an interview he gave to Russ Roberts at in 2015 he reveals his inability to grasp even the most basic science:

“So, why do they say that their estimate of climate sensitivity, which is the amount of warming from a doubling, is 3 degrees? Not 1 degree? And the answer is because the models have an amplifying factor in there. They are saying that that small amount of warming will trigger a furtherwarming, through the effect mainly of water vapor and clouds. In other words, if you warm up the earth by 1 degree, you will get more water vapor in the atmosphere, and that water vapor is itself a greenhouse gas and will cause you to treble the amount of warming you are getting. Now, that’s the bit that lukewarmers like me challenge. Because we say, ‘Look, the evidence would not seem the same, the increases in water vapor in the right parts of the atmosphere–you have to know which parts of the atmosphere you are looking at–to justify that. And nor are you seeing the changes in cloud cover that justify these positive-feedback assumptions. Some clouds amplify warming; some clouds do the opposite–they would actually dampen warming. And most of the evidence would seem to suggest, to date, that clouds are actually having a dampening effect on warming. So, you know, we are getting a little bit of warming as a result of carbon dioxide. The clouds are making sure that warming isn’t very fast. And they’re certainly not exaggerating or amplifying it. So there’s very, very weak science to support that assumption of a trebling.”

He seems to be saying that the water vapour is in the form of clouds – some high altitude, some low –  have opposite effects (so far, so good), so the warming should be 1C – just the carbon dioxide component – from a doubling of CO2 concentrations (so far, so bad).  The clouds represent a condensed (but not yet precipitated) phase of water in the atmosphere, but he seems to have overlooked that water also comes in a gaseous phase (not clouds). Its is that gaseous phase that is providing the additional warming, bringing the overall warming to 3C.

The increase in water vapour concentrations is based on “a well-established physical law (the Clausius-Clapeyron relation) determines that the water-holding capacity of the atmosphere increases by about 7% for every 1°C rise in temperature” (IPCC AR4 FAQ 3.2)

T.C. Chamberlin writing in 1905 to Charles Abbott, explained this in a way that is very clear, explaining the feedback role of water vapour:

“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 …”

(Ref. “Historical Perspectives On Climate Change” by James Fleming, 1998)

It is now 113 years since Chamberlin wrote those words, but poor Ridley is still struggling to understand basic physics, so instead regales us with dubious science intended to distract and confuse.

When will Matt Ridley stop feeling the need to share his perpetual incredulity and obdurate ignorance with the world?

© Richard W. Erskine, 2018

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Incredulity, Credulity and the Carbon Cycle

Incredulity, in the face of startling claims, is a natural human reaction and is right and proper.

When I first heard the news about the detection on 14th September 2015 of the gravitational waves from two colliding black holes by the LIGO observatories I was incredulous. Not because I had any reason to disagree with the predictions of Albert Einstein that such waves should exist, rather it was my incredulity that humans had managed to detect such a small change in space-time, much smaller than the size of a proton.

How, I pondered, was the ‘noise’ from random vibrations filtered out? I had to do some studying, and discovered the amazing engineering feats used to isolate this noise.

What is not right and proper is to claim that personal incredulity equates to an error in the claims made. If I perpetuate my incredulity by failing to ask any questions, then it’s I who is culpable.

And if I were to ask questions then simply ignore the answers, and keep repeating my incredulity, who is to blame? If the answers have been sufficient to satisfy everyone skilled in the relevant art, how can a non expert claim to dispute this?

Incredulity is a favoured tactic of many who dispute scientific findings in many areas, and global warming is not immune from the clinically incredulous.

The sadly departed Professor David Mackay gives an example in his book Sustainable Energy Without the Hot Air (available online):

The burning of fossil fuels is the principal reason why CO2 concentrations have gone up. This is a fact, but, hang on: I hear a persistent buzzing noise coming from a bunch of climate-change inactivists. What are they saying? Here’s Dominic Lawson, a columnist from the Independent:  

“The burning of fossil fuels sends about seven gigatons of CO2 per year into the atmosphere, which sounds like a lot. Yet the biosphere and the oceans send about 1900 gigatons and 36000 gigatons of CO2 per year into the atmosphere – … one reason why some of us are sceptical about the emphasis put on the role of human fuel-burning in the greenhouse gas effect. Reducing man-made CO2 emissions is megalomania, exaggerating man’s significance. Politicians can’t change the weather.”

Now I have a lot of time for scepticism, and not everything that sceptics say is a crock of manure – but irresponsible journalism like Dominic Lawson’s deserves a good flushing.

Mackay goes on to explain Lawson’s error:

The first problem with Lawson’s offering is that all three numbers that he mentions (seven, 1900, and 36000) are wrong! The correct numbers are 26, 440, and 330. Leaving these errors to one side, let’s address Lawson’s main point, the relative smallness of man-made emissions. Yes, natural flows of CO2 are larger than the additional flow we switched on 200 years ago when we started burning fossil fuels in earnest. But it is terribly misleading to quantify only the large natural flows into the atmosphere, failing to mention the almost exactly equal flows out of the atmosphere back into the biosphere and the oceans. The point is that these natural flows in and out of the atmosphere have been almost exactly in balance for millenia. So it’s not relevant at all that these natural flows are larger than human emissions. The natural flows cancelled themselves out. So the natural flows, large though they were, left the concentration of CO2 in the atmosphere and ocean constant, over the last few thousand years.

Burning fossil fuels, in contrast, creates a new flow of carbon that, though small, is not cancelled.

I offer this example in some detail as an exemplar of the problem often faced in confronting incredulity.

It is natural that people will often struggle with numbers, especially large abstract sounding numbers. It is easy to get confused when trying to interpret numbers. It does not help that in Dominic Lawson’s case he is ideologically primed to see a ‘gotcha’, where none exists.

Incredulity, such as Lawson’s, is perfectly OK when initially confronting a claim that one is sceptical of; we cannot all be informed on every topic. But why then not pick up the phone, or email a Professor with skills in the particular art, to get them to sort out your confusion?  Or even, read a book, or browse the internet? But of course, Dominic Lawson, like so many others suffers from a syndrome that  many have identified. Charles Darwin noted in The Descent of Man:

“Ignorance more frequently begets confidence than does knowledge: it is those who know little, not those who know much, who so positively assert that this or that problem will never be solved by science.”

It is this failure to display any intellectual curiosity which is unforgivable in those in positions of influence, such as journalists or politicians.

However, the incredulity has a twin brother, its mirror image: credulity. And I want to take an example that also involves the carbon cycle,.

In a politically charged subject, or one where there is a topic close to one’s heart, it is very easy to uncritically accept a piece of evidence or argument. To be, in the technical sense, a victim of confirmation bias.

I have been a vegetarian since 1977, and I like the idea of organic farming, preferably local and fresh. So I have been reading Graham Harvey’s book Grass Fed Nation. I have had the pleasure of meeting Graham, as he was presenting a play he had written which was performed in Stroud. He is a passionate and sincere advocate for his ideas on regenerative farming, and I am sure that much of what he says makes sense to farmers.

The recently reported research from Germany of a 75% decline in insect numbers is deeply worrying, and many are pointing the finger at modern farming and land-use methods.

However, I found something in amongst Harvey’s interesting book that made me incredulous, on the question of carbon.

Harvey presents the argument that, firstly, we can’t do anything to reduce carbon emissions from industry etc., but that secondly, no need to worry because the soils can take up all the annual emissions with ease; and further, that all of extra carbon in the industrial era could be absorbed in soils over coming years.

He relies a lot on Savory’s work, famed for his visionary but contentious TED talk. But he also references other work that makes similar claims.

I would be lying if I said there was not a part of me that wanted this to be true. I was willing it on. But I couldn’t stop myself … I just had to track down the evidence. Being an ex-scientist, I always like to go back to the source, and find a paper, or failing that (because of paywalls), a trusted source that summarises the literature.

Talk about party pooper, but I cannot find any such credible evidence for Harvey’s claim.

I think the error in Harvey’s thinking is to confuse the equilibrium capacity of the soils with their ability to take up more, every year, for decades.

I think it is also a inability to deal with numbers. If you multiply A, B and C together, but then take the highest possible ranges for A, B and C you can easily reach a result which is hugely in error. Overestimate the realistic land that can be addressed; and the carbon dioxide sequestration rate; and the time till saturation/ equilibrium is reached … and it is quite easy to overestimate the product of these by a factor of 100 or more.

Savory is suggesting 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.

There are many complex processes at work in the whole carbon cycle – the biological, chemical and geological processes covering every kind of cycle, with flows of carbon into and out of the carbon sinks. Despite this complexity, and despite the large flows of carbon (as we saw in the Lawson case), atmospheric levels had remained stable for a long time in the pre-industrial era (at 280 parts per million).  The Earth system as a whole was in equilibrium.

The deep oceans have by far the greatest carbon reservoir, so a ‘plausibility argument’ could go along the lines of: the upper ocean will absorb extra CO2 and then pass it to the deep ocean. Problem solved! But this hope was dashed by Revelle and others in the 1950s, when it was shown that the upper-to-lower ocean processes are really quite slow.

I always come back to the Keeling Curve, which reveals an inexorable rise in CO2 concentrations in the atmosphere since 1958 (and we can extend the curve further back using ice core data). And the additional CO2 humans started to put into the atmosphere since the start of the industrial revolution (mid-19th century, let us say) was not, as far as I can see, magically soaked up by soils in the pre-industrial-farming days of the mid-20th century, when presumably traditional farming methods pertained.

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. A nice cop-out there.

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).

It is interesting what we see here.

An example of ‘incredulity’ from Lawson, who gets carbon flows mixed up with net carbon flow, and an example of ‘credulity’ from Harvey where he puts too much stock in the equilibrium capacity of carbon in the soil, and assumes this means soils can keep soaking up carbon almost without limit. Both seem to struggle with basic arithmetic.

Incredulity in the face of startling claims is a good initial response to startling claims, but should be the starting point for engaging one’s intellectual curiosity, not as a perpetual excuse for confirming one’s bias; a kind of obdurate ignorance.

And neither should hopes invested in the future be a reason for credulous acceptance of claims, however plausible on face value.

It’s boring I know – not letting either one’s hopes or prejudices hold sway – but maths, logic and scientific evidence are the true friends here.

Maths is a great leveller.


(c) Richard W. Erskine, 2017


Filed under Climate Science, Essay, Uncategorized