Category Archives: Climate Science

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

 

NOTES

(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).

END

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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!

*CUT TO REAL WORLD*

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

Footnotes

  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.”

References

  • 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:

spiral_2017_large

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

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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).

Conclusion

Matt Ridley in an interview he gave to Russ Roberts at EconTalk.org 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. www.drawdown.org) 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

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Beyond Average: Why we should worry about a 1 degree C rise in average global temperature

When I go to the Netherlands I feel small next to men from that country, but then I am 3 inches smaller than the average Brit, and the average Dutchman is 2 inches taller than the average Brit. So I am seeing 5 inches of height difference in the crowd around me when surrounded by Dutch men. No wonder I am feeling an effect that is much greater than what the average difference in height seems to be telling me on paper.

Averages are important. They help us determine if there is a real effect overall. Yes, men from the Netherlands are taller than men from Britain, and so my impressions are not merely anecdotal. They are real, and backed up by data.

If we are wanting to know if there are changes occurring, averages help too, as they ensure we are not focusing on outliers, but on a statistically significant trend. That’s not to say that it is always easy to handle the data correctly or to separate different factors, but once this hard work is done, the science and statistics together can lead us to knowing important things, with confidence.

For example, we know that smoking causes lung cancer and that adding carbon dioxide into the atmosphere leads to increased global warming.

But, you might say, correlation doesn’t prove causation! Stated boldly like that, no it doesn’t. Work is required to establish the link.

Interestingly, we knew the fundamental physics of why carbon dioxide (CO2) is a causative agent for warming our atmosphere – not merely correlated – since as early as Tyndall’s experiments which he started in 1859, but certainly no later than 1967, when Manabe & Wetherald’s seminal paper resolved some residual physics questions related to possible saturation of the infra-red  absorption in the atmosphere and the co-related effect of water vapour. That’s almost 110 years of probing, questioning and checking. Not exactly a tendency on the part of scientists to rush to judgment! And in terms of the correlation being actually observed in our atmosphere, it was Guy Callendar in 1938 who first published a paper showing rising surface temperature linked to rising levels of CO2.

Whereas, in the case of lung cancer and cigarettes correlation came first, not fundamental science. It required innovations in statistical methods to prove that it was not merely correlation but was indeed causation, even while the fundamental biological mechanisms were barely understood.

In any case, the science and statistics are always mutually supportive.

Average Global Warming

In the discussions on global warming, I have been struck over the few years that I have been engaging with the subject how much air time is given to the rise in atmospheric temperature, averaged for the whole of the Earth’s surface, or GMST as the experts call it (Global Mean Surface Temperature).  While it is a crucial measure, this can seem a very arcane discussion to the person in the street.

So far, it has risen by about 1 degree Centigrade (1oC) compared to the middle of the 19th Century.

There are regular twitter storms and blogs ‘debating’ a specific year, and last year’s El Nino caused a huge debate as to what this meant. As it turns out, the majority of recent warming is due to man-made global warming, and this turbo-charged the also strong El Nino event.

Anyone daring to take a look at the blogosphere or twitter will find climate scientists arguing with opinion formers ill equipped to ‘debate’ the science of climate change, or indeed, the science of anything.

What is the person in the street supposed to make of it? They probably think “this is not helping me – it is not answering the questions puzzling me – I can do without the agro thanks very much”.

To be fair, many scientists do spend a lot of time on outreach and in other kinds of science communications, and that is to be applauded. A personal favourite of mine is Katharine Hayhoe, who always brings an openness and sense of humility to her frequent science communications and discussions, but you sense also, a determined and focused strategy to back it up.

However, I often feel that the science ‘debate’ generally gets sucked into overly technical details, while basic, or one might say, simple questions remain unexplored, or perhaps assumed to be so obvious they don’t warrant discussion.

The poor person in the street might like to ask (but dare not for fear of being mocked or being overwhelmed with data), simply:

“Why should we worry about an average rise of 1oC temperature, it doesn’t seem that much, and with all the ups and downs in the temperature curve; the El Nino; the alleged pause; the 93% of extra heat going into the ocean I heard about … well, how can I really be sure that the surface of the Earth is getting warmer?”

There is a lot to unpick here and I think the whole question of ‘averages’ is part of the key to approaching why we should worry.

Unequivocally Warming World

Climate Scientists will often show graphs which include the observed and predicted annual temperature (GMST) over a period of 100 years or more.

Now, I ask, why do they do that?

Surely we have been told to that in order to discern a climate change trend, it is crucial to look at the temperature averaged over a period of at least 10 years, and actually much better to look at a 30-year average?

In this way we smooth out all the ups and downs that are a result of the energy exchanges that occur between the moving parts of the earth system, and the events such as volcanic eruptions or humans pumping less sulphur into the atmosphere from industry. We are interested in the overall trend, so we can see the climate change signal amongst the ‘noise’.

We also emphasis to people – for example, “the Senator with a snowball” – that climate change is about averages and trends, as distinct from weather (which is about the here and now).

So this is why the curve I use – when asked “What is the evidence that the world is warming?” – is a 30-year smoothed curve (red line) such as the one shown below (which used the GISS tool):

30 yr rolling average of GMST

[also see the Met Office explainer on global surface temperature]

The red line shows inexorable warming from early in the 20th Century, no ifs, no buts.

End of argument.

When I challenged a climate scientist on Twitter, why don’t we just show this graph and not get pulled into silly arguments with a Daily Mail journalist or whoever, I was told that annual changes are interesting and need to be understood.

Well sure, for climate scientists everything is interesting! They should absolutely try to answer the detailed questions, such as the contribution global warming made to the 2016 GMST. But to conflate that with the simpler and broader question does rather obscure the fundamental message for the curious but confused public who have not even reached base camp.

They may well conclude there is a ‘debate’ about global warming when there is none to be had.

There is debate amongst scientists about many things: regional impact and attribution; different feedback mechanisms and when they might kick in; models of the Antarctic ice sheet; etc. But not about rising GMST, because that is settled science, and given Tyndall et al, it would be incredible if it were not so; Nobel Prize winning incredible!

If one needs a double knock-out, then how about a triple or quadruple knock-out?

When we add the graphs showing sea level rise, loss of glaciers, mass loss from Greenland and Antarctica, and upper ocean temperature, we have multiple trend lines all pointing in one direction: A warming world. It ain’t rocket science.

We know the world has warmed – it is unequivocal.

Now if a the proverbial drunk, duly floored, still decides to get up and wants to rerun the fight, maybe we should be choosing not to play his games!?

So why do arguments about annual variability get so frequently aired on the blogosphere and twitter?

I don’t know, but I feel it is a massive own goal for science communication.

Surely the choice of audience needs to be the poor dazed and confused ‘person in the street’, not the obdurately ignorant opinion columnists (opinion being the operative word).

Why worry about a 1oC rise?

I want to address the question “Why worry about a 1oC rise (in global mean surface temperature)?”, and do so with the help of a dialogue. It is not a transcript, but along the lines of conversations I have had in the last year. In this dialogue, I am the ClimateCoach and I am in conversation with a Neighbour who is curious about climate change, but admits to being rather overwhelmed by it; they have got as far as reading the material above and accept that the world is warming.

Neighbour:  Ok, so the world is warming, but I still don’t get why we should worry about a measly 1oC warming?

ClimateCoach: That’s an average, over the whole world, and there are big variations hidden in there. Firstly, two thirds of the surface of the planet is ocean, and so over land we are already talking about a global land mean surface temperature in excess of 1oC, about 1.5oC. That’s the first unwelcome news, the first kicker.

Neighbour: So, even if it is 5oC somewhere, I still don’t get it. Living in England I’d quite like a few more Mediterranean summers!

ClimateCoach: Ok, so let’s break this down (and I may just need to use some pictures).  Firstly we have an increase in the mean, globally. But due to meteorological patterns there will be variations in temperature and also changes in precipitation patterns around the world, such as droughts in California and increased Monsoon rain in India. This  regionality of the warming is the second kicker.

Here is an illustration of how the temperature increase looks regionally across the world.

GISTEMP global regional

Neighbour: Isn’t more rain good for Indian farmers?

ClimateCoach: Well, that depends on timing. It has started to be late, and if it doesn’t arrive in time for certain crops, that has serious impacts. So the date or timing of impacts is the third kicker.

Here is an illustration.

Screen Shot 2017-04-15 at 08.45.34.png

Neighbour: I noticed earlier that the Arctic is warming the most. Is that a threat to us?

ClimateCoach: Depends what you mean by ‘us’. There is proportionally much greater warming in the Arctic, due to a long-predicted effect called ‘polar amplification’, in places as much as 10oC of warming. As shown in this map of the arctic. But what happens in the Arctic doesn’t stay in the Arctic.

Arctic extremes

Neighbour: I appreciate that a warming Arctic is bad for ecosystems in the Arctic – Polar Bears and so on – but why will that effect us?

ClimateCoach: You’ve heard about the jet stream on the weather reports, I am sure [strictly, the arctic polar jet stream]. Well, as the Arctic is warmed differentially compared to latitudes below the Arctic, this causes the jet stream to become more wiggly than before, which can be very disruptive. This can create, for example, fixed highs over Europe, and very hot summers.

Neighbour: But we’ve had very hot summers before, why would this be different?

ClimateCoach: It’s not about something qualitatively different (yet), but it is quantitatively. Very hot summers in Europe are now much more likely due to global warming, and that has real impacts. 70,000 people died in Europe during the 2003 heatwave.  Let me show you an illustrative graph. Here is a simple distribution curve and it indicates a temperature at and above which (blue arrow) high impacts are expected, but have a low chance. Suppose this represents the situation in 1850.

Normal distribution

Neighbour: Ok, so I understand the illustration … and?

ClimateCoach: So, look at what happens when we increase the average by just a little bit to a higher temperature, say, by 1oC to represent where we are today. The whole curve shifts right. The ‘onset of high impact’ temperature is fixed, but the area under the curve to the right of this has increased (the red area has increased), meaning a greater chance than before. This is the fourth kicker.

In our real world example, a region like Europe, the chance of high impact hot summers has increased within only 10 to 15 years from being a one in 50 year event to being a 1 in 5 year event; a truly remarkable increase in risk.   

Shifted Mean and extremes

Neighbour: It’s like loading the dice!

ClimateCoach: Exactly. We (humans) are loading the dice. As we add more CO2 to the atmosphere, we load the dice even more. 

Neighbour: Even so, we have learned to cope with very hot summers, haven’t we? If not, we can adapt, surely?

ClimateCoach: To an extent yes, and we’ll have to get better at it in the future. But consider plants and animals, or people who are vulnerable or have to work outside, like the millions of those from the Indian sub-continent who work in construction in the Middle East.  It doesn’t take much (average) warming to make it impossible (for increasingly long periods) to work outside without heat exhaustion. And take plants. A recent paper in Nature Communications showed that crop yields in the USA would be very vulnerable to excessive heat.

Neighbour: Can’t the farmers adapt by having advanced irrigation systems. And didn’t I read somewhere that extra CO2 acts like a fertiliser for plants?

ClimateCoach: To a point, but what that research paper showed was that the warming effect wins out, especially as the period of excessive heat increases, and by the way the fertilisation effect has been overstated. The extended duration of the warming will overwhelm these and other ameliorating factors. This is the fifth kicker.

This can mean crop failures and hence impacts on prices of basic food commodities, even shortages as impacts increase over time.

Neighbour: And what if we get to 2oC?  (meaning 2oC GMST rise above pre-industrial)

ClimateCoach: Changes are not linear. Take the analogy of car speed and pedestrian fatalities. After 20 miles per hour the curve rises sharply, because the car’s energy is a function of the square of the speed, but also the vulnerability thresholds in the human frame. Global warming will cross thresholds for both natural and human systems, which have been in balance for a long time, so extremes get increasingly disruptive. Take an impact to a natural species or habitat: one very bad year, and there may be recovery in the following 5-10 years, which is ok if the frequency of very bad years is 1 in 25-50 years. But suppose very bad years come 1 in every 5 years? That would mean no time to recover. Nature is awash with non-linearities and thresholds like this.

Neighbour: Is that what is happening with the Great Barrier Reef – I heard something fleetingly on BBC Newsnight the other night?

ClimateCoach: I think that could be a very good example of what I mean. We should talk again soon. Bring friends. If they want some background, you might ask them to have a read of my piece Demystifying Global Warming & Its Implications, which is along the lines of a talk I give.

Putting it together for the person in the street.

I have explored one of many possible conversations I could have had. I am sure it could be improved upon, but I hope it illustrates the approach. We should be engaging those people (the majority of the population) who are curious about climate change but have not involved themselves so far, perhaps because they feel a little intimidated by the subject.

When they do ask for help, the first thing they need to understand is that indeed global warming is real, and is demonstrated by those average measures like GMST, and the other ones mentioned such as sea-level rise, ice sheet mass loss, and ocean temperature; not to mention the literally thousands of indicators from the natural world (as documented in the IPCC 5th Assessment Report).

There are also other long-term unusual sources of evidence to add to this list, as Dr Ed Hawkins has discussed, such as the date at which Cherry blossom flowers in Kyoto, which is trending earlier and earlier.  Actually, examples such as these, are in many ways easier for people to relate to.

Gardeners the world over can relate to evidence of cherry blossom, wine growers to impacts on wine growing regions in France, etc. These diverse and rich examples are in many ways the most powerful for a lay audience.

The numerous lines of evidence are overwhelming.

So averages are crucial, because they demonstrate a long-term trend.

When we do raise GMST, make sure you show the right curve. If it is to show unequivocal global warming at the surface, then why not show one that reflects the average over a rolling 30 year period; the ‘smoothed’ curve. This avoids getting into debates with ‘contrarians’ on the minutae of annual variations, which can come across as both abstract and arcane, and puts people off.

This answers the first question people will be asking, simply: “Is the world warming?”. The short answer is “Unequivocally, yes it is”. And that is what the IPCC 5th Assessment Report concluded.

But averages are not the whole story.

There is the second but equally important question “Why worry about a 1oC rise (in global mean surface temperature)?”

I suspect many people are too coy to ask such a simple question. I think it deserves an answer and the dialogue above tried to provide one.

Here and now, people and ecosystems experience weather, not climate change, and when it is an extreme event, the impacts are viscerally real in time and place, and are far from being apparently arcane debating points.

So while a GMST rise of 1oC sounds like nothing to the untutored reader, when translated into extreme weather events, it can be highly significant.  The average has been magnified to yield a significant effect, as evidenced by the increasing chance of extreme events of different kinds, in different localities, which can increasingly be attributed to man-made global warming.

The kickers highlighted in the dialogue were:

  • Firstly, people live on land so experience a higher ‘GMST’ rise (this is not to discount the impacts on oceans);
  • Secondly, geographical and meteorological patterns mean that there are a wide range of regional variations;
  • Thirdly, the timing (or date) at which an impact is felt is critical for ecosystems and agriculture, and bad timing will magnify the effect greatly;
  • Fourthly, as the average increases, so does the chance of extremes. The dice are getting loaded, and as we increase CO2, we load the dice more.
  • Fifthly, the duration of an extreme event will overwhelm defences, and an extended duration can cross dangerous thresholds, moving from increasing harm into fatal impacts, such as crop failure.

I have put together a graphic to try to illustrate this sequence of kickers:

Screen Shot 2017-04-15 at 08.36.37.png

As noted on this graphic (which I used in some climate literacy workshops I ran recently), the same logic used for GMST can be applied to other seemingly ‘small’ changes in global averages such as rainfall, sea-level rise, ocean temperature and ocean acidification. To highlight just two of these other examples:

  • an average global sea-level rise translates into impacts such as extreme storm surges, damaging low-lying cities such as New York and Miami (as recently reported and discussed).
  • an average ocean temperature rise, translates into damage to coral reefs (two successive years of extreme events have caused serious damage to two thirds of the Great Barrier Reef, as a recent study has confirmed).

Even in the relatively benign context of the UK’s temperate climate, the Royal Horticultural Society (RHS), in a report just released, is advising gardeners on climate change impacts and adaptation. The instinctively conservative ‘middle England’ may yet wake up to the realities of climate change when it comes home to roost, and bodies such as the RHS reminds them of the reasons why.

The impacts of man-made global warming are already with us, and it will only get worse.

How much worse depends on all of us.

Not such a stupid question

There was a very interesting event hosted by CSaP (Centre for Science and Policy) in Cambridge recently. It introduced some new work being done to bring together climate science and ‘big data analytics’. Dr Emily Schuckburgh’s talk looked precisely at the challenge of understanding local risks; the report of the talk included the following observation:

“Climate models can predict the impacts of climate change on global systems but they are not suitable for local systems. The data may have systematic biases and different models produce slightly different projections which sometimes differ from observed data. A significant element of uncertainty with these predictions is that they are based on our future reduction of emissions; the extent to which is yet unknown.

To better understand present and future climate risks we need to account for high impact but low probability events. Using more risk-based approaches which look at extremes and changes in certain climate thresholds may tell us how climate change will affect whole systems rather than individual climate variables and therefore, aid in decision making. Example studies using these methods have looked at the need for air conditioning in Cairo to cope with summer heatwaves and the subsequent impact on the Egyptian power network.”

This seems to be breaking new ground.

So maybe the eponimous ‘person in the street’ is right to ask stupid questions, because they turn out not to be so stupid after all.

Changing the Conversation

I assume that the person in the street is curious and has lots of questions; and I certainly don’t judge them based on what newspaper they read. That is my experience. We must try to anticipate and answer those questions, and as far as possible, face to face. We must expect simple questions, which aren’t so stupid after all.

We need to change the focus from the so-called ‘deniers’ or ‘contrarians’ – who soak up so much effort and time from hard pressed scientists – and devote more effort to informing the general public, by going back to the basics. By which I mean, not explaining ‘radiative transfer’ and using technical terms like ‘forcing’, ‘anomaly’, or ‘error’, but using plain English to answer those simple questions.

Those embarrasingly stupid questions that will occur to anyone who first encounters the subject of man-made global warming; the ones that don’t seem to get asked and so never get answered.

Maybe let’s start by going beyond averages.

No one will think you small for doing so, not even a Dutchman.

[updated 15th April]

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