CHAOS AND CLIMATE

At a time of chaos in national politics (with our new UK prime minister) and international crisis, it may seem frivolous to write about the mathematical concepts of chaos theory. Analogies can indeed be drawn between seemingly trivial chance events in politics and “chaotic” or seemingly unpredictable situations and outcomes like Brexit. But this blog is concerned primarily with energy, low carbon, and climate issues and policies, to which the world will be increasingly turning its attention when Brexit is done and dusted. In the absence of much immediate policy discussion on that front, it is perhaps a good time to cover a subject that is at the same time both arcane and interesting, and to speculate on what we might learn from that discussion.
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Could a butterfly flapping its wings in China set off a tornado in Texas? This rather fanciful idea is of course incapable of being tested, but it has nevertheless been used to describe chaos theory, and is in reality rather misleading. Since weather and climate systems are indeed genuinely “chaotic” as defined in terms of the mathematics of chaos theory, it is important to understand what this might mean for our understanding of climate science, and what chaos theory might or might not tell us about predicting either weather or climate.

Chaos in this context does not have quite the same meaning as chaos in everyday language. So it is worth stressing what it does not mean.

·         Chaotic behaviour does not mean behaviour that is not governed by well understood rules.

 ·         Chaos is not the same as mere complexity.

 ·         Chaos is not the same as unpredictability.

 ·         Nor does it imply randomness.

 ·         The chaotic nature of a system does not mean that we cannot develop important understandings of the nature and frequency of its future states

The definition of a chaotic system, in the mathematical sense, is one in which very small changes in the initial conditions, sometimes called boundary conditions, will have a very large impact on the actual state of the system at more distant points in the future. It is comparatively easy to find examples, even in the relatively simple world of Newtonian mechanics, and one does not need to assume the deeper uncertainties of quantum theory, or waste time on the rather fanciful and unverifiable claims about the impact of a butterfly’s wings.

All of this matters in understanding what chaos theory can tell us in relation to climate and weather. The close connection is emphasised by fact that it was a climatologist, Edward Lorenz, who is credited as one of the founders of chaos theory.  The phenomenon is closely associated with the differential equations that can be used to describe weather and climate systems.

One of the best (because it is simple) illustrations of the nature of chaotic systems is provided by the double pendulum – two rods hinged at their junction, with a weight at the end of each.

https://math24.net/double-pendulum.html

The article explains the nature of the double pendulum. Its behaviour is governed simply by Newtonian mechanics, and can be described by a set of differential equations, which are solved in order to produce the simulated behaviour that the article then illustrates.

The reader is invited to experiment with this link, changing the relative size of the weights and the initial angle, which corresponds to the amount of potential energy the system has at the start. When the system is charged with relatively low amounts of energy, its pattern remains fairly close to that of a conventional single pendulum, and will continue in this pattern indefinitely, as we can see from the picture below. 

However a small increase in the amount of energy above a certain level creates a highly chaotic system, observed in the second picture, and giving rise to much more complex and unusual patterns of motion.

So what analogies might we draw from this simple example. I suggest there are two.

The first is simply that the injection of more energy into any physical system tends to make it more turbulent and chaotic, something that will seem intuitively clear to many people. In the case of weather and climate, the extra energy is the "warming" injected by radiative forcing. Its effects might include obviously turbulent events such as hurricanes, but might simply mean a wider variety of new or unusual weather and climate patterns. Identifying those possibilities is of course a significant part of what climate science is about.

A second analogy is that there are indeed “tipping points” or extreme non-linearities of response. At a certain point the extra energy injected into the system, raising the initial angle from 75 to 79 degrees, induces much more unstable and "chaotic" behaviour, and a much wider range of "extreme" events. The parallels with the dispute over tipping points, often ridiculed by climate sceptics, are clear. Far from being speculative scare stories, the illustration shows that tipping points can be a major feature of even highly simplified chaotic systems.

TIME TO DEMOLISH SCEPTICISM OVER CLIMATE SCIENCE.

If effective policies to reduce emissions catch the popular imagination we can expect a counter from the vested interests, both financial and more importantly ideological, opposed to any action. We can expect the reiteration of bad arguments and untruths, so let’s try to clear up some of the sillier bits of misinformation that keep doing the rounds.

There are at last a few signs (school climate strikes, activist demonstrations, and some belated political recognition of an “emergency”) that the issue of climate change is starting to gain popular traction. The climate sceptics are still, sadly, out there, although many are currently keeping very quiet. This silence is unlikely to persist as policy debates unfold, so it may be a useful time to reflect on and counter the classic techniques of disinformation, fallacious argument and political rhetoric that they employ. I have chosen a 2017 piece by Melanie Phillips  as an illustration, partly because the author (MP) is a well-known, articulate and persistent sceptic, and partly because a relatively recent 2017 posting illustrates in a short comment a number of typical fallacies and untruths about climate. But the same approaches to argument are very widespread in much of the popular and political discourse on climate issues.

One feature is routine abuse. Words or language such as “climate hoax” (Trump), “scam”, “climate alarmism” or “conspiracy” are regularly used in attempts to discredit both a serious body of science and the great majority of scientists. More subtly, a “dogwhistle politics” approach is used to associate climate science with religious belief, the implication being that the science is based on personal faith rather than hard evidence, or with political ideology.^[1]  And the latest “Brexit era” abuse, when it comes to discussing possible policies on climate, has been clearly illustrated by the personal attacks on teenager Greta Thunberg.[2] The slur is of course that this is an “elite” obsession, as if only middle class, Waitrose shoppers were concerned about the future of their children or grandchildren.

But fallacy and dishonesty begin in earnest with the construction of the “straw men”, the attribution of opinions or statements not actually held or expressed by any serious climate scientist but which the author (in this case MP) feels able to refute. 

Create straw men and misrepresent your adversary.

Global warming theory rests on the belief that rising CO2 levels drive up atmospheric temperature. (MP). Wrong. It does not rest on “belief” (note the word used), but on the certain knowledge that particular gases, of which CO2 is the most relevant, have a significant radiative forcing impact, and the certain knowledge that anthropogenic emissions have been and are increasing atmospheric concentrations of many of those gases. This then leads to analysis based on a broadly based and growing body of science, and study of two complex and closely interrelated systems, the climate system itself and the natural carbon cycle. The results are estimates of the projected future impact on global temperatures and climate, and hence the nature of the associated risks, associated with policies that fail to mitigate GHG emissions. So far those estimates, despite natural cycles and other statistical noise, have been disturbingly close to actual observed trends[3].

But there is no straightforward link between CO2 and temperature. (MP).  And no climate scientist ever claims the link is straightforward? The science has never claimed either that CO₂ is the sole determinant of climate, or that there are not substantial natural cycles, significant time lags, measurement error, or that there is not consequent “noise” in climate data. Both the climate system and the carbon cycle are intrinsically complex. They are interrelated. Outcomes, and hence comparison with any predictions, can be affected both by unforeseen elements such as volcanic activity, variations in solar radiation, and errors in measurement or in assumptions, for example on future GHG emissions. But naturally the pretence that climate science offers a simple relationship makes it easier to generate spurious evidence that appears to falsify (following Popperian principle) the core finding, that GHG emissions are the likely cause of currently observed warming and a large threat for the future. 

Just invent some alternative facts.

Observable fluctuations in global temperature are within the normal historic pattern of atmospheric variation. (MP)

This is clearly untrue, and rather obviously so. Systematic annual global temperature records are of course a relatively recent phenomenon.  Comprehensive global temperature data only dates back to 1850, and estimates of global temperature earlier in history are to a large degree speculative[4]. As can be seen from the chart below, the world has now moved well outside its 1850-1980[5] range. Within the “historic pattern” available to us, a casual observer might argue that there had been little or no significant change between 1880 and the late 1970s, followed thereafter by an apparently rapid trend increase. This description of a broad pattern happens to fit quite neatly, with an expected time lag, to the explosive growth of emissions from the 1950s, and consequent rise in GHG concentrations. 

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This brings us to the next tool of the sceptic trade - selective use of irrelevant information to make absurd comparisons. The MP article has some good examples, much of which is related to interesting real science even if it is beyond the periphery of what is currently most relevant. These include introduction of geological or cosmological timescales that are largely irrelevant to human concerns, and focus on peripherally significant indicators such as Antarctic sea ice or polar bear populations.

An entirely different timescale

Historically, temperature increases have often preceded high CO2 levels, destroying this theory of cause and effect. Moreover, there have been periods when atmospheric CO2 levels were as much as 16 times what they are now, periods characterised not by warming but by glaciation. (MP)

Introduction of this comparison as relevant evidence is absurd. Planet Earth, and a climate with CO₂ at 16 times current levels, describes a planet and solar system of 400 million years ago or more. This is an interesting subject but it was a world very different from our own. Solar radiation from a younger sun is estimated to have been significantly lower, and in consequence consistent with much higher CO₂ for any given temperature. The carbon cycle, at a time when plants were still colonising the land, would have been completely different. Known carbon removal mechanisms (eg from temperature to weathering rock) are very relevant to explaining changes over tens or hundreds of millions of years. But these are processes operating on geological or even cosmological timescales. Their parameters have rather less importance in understanding the timescales with which most of current climate science is concerned.

Other measures indicate that CO₂ concentrations (see NOAA ice core data above) have been substantially below current levels throughout the last 800,000 years. The most important climate science, as one might expect, is concerned with the parameters of our planet as it is now, with what is observable on human timescales, and with effects on human timescales.

Cherry pick statistics from secondary indicators.

The icecaps are not generally melting; Antarctic ice is actually increasing. (MP)

Polar ice is, for NASA, one of the “vital signs” of climate. But it is always dangerous to base an argument by cherry picking among secondary indicators, at least without a good understanding of their limitations. Antarctic sea ice is a favourite choice for supposed contra-indications. Without pursuing the subject in depth, this indicator is generally considered  subject to significant natural variation, even in the absence of warming. As it happens, Antarctic sea ice area in January 2019 was the second lowest of any January since the start of the data record in 1979. This would therefore appear to signify the opposite of MP’s conclusion, but the fall is not currently seen by climate scientists as predominantly due to overall warming. 

Arctic sea ice is the more significant factor in amplifying warming tendencies, by reducing the albedo (reflection) effect, and has shown more dramatic and consistent reductions over a longer period, something easily verified from aerial mapping.  

As for land ice[6], the most recent data from NASA's GRACE satellites show that the land ice sheets in both Antarctica (upper chart) and Greenland (lower) have been losing mass since 2002. Both have seen an acceleration of ice mass loss since 2009. One previous (2015)  NASA study (Zwally et al), used different methods, and did appear to contradict previous measurements of Antarctic ice. However even at the time the lead author of this study was at pains to point out that the results, assuming they were accurate, did nothing to contradict the scientific consensus on climate change, or the view that sea levels would continue to rise. He astutely predicted that climate science deniers would distort the study.

Polar bears are increasing in number. (MP)

Polar bear numbers are hard to measure and there appear to be no reliable statistics. Other factors, such as restrictions on hunting, or available food, are present. Bears may or may not be able to cope with reduced ice cover, but bear numbers are not per se a measure of climate change, either as victims or beneficiaries.  

There is no upward trend in the occurrence of virtually any extreme events …. (MP)

Extreme events do not “prove” climate change, and it is impossible to attribute an individual weather event to climate change. But greater frequency or severity is entirely consistent with it. A priori the injection of more energy into any system (which is what warming amounts to) will tend to produce more turbulent outcomes. More recent science has attempted with some success to draw an explicit link in terms of probabilities. The chart below shows one particular example.

Finally, disbelieve human capacity to find meaning, understanding and order in complex and chaotic systems. 

The assumption that highly complex natural systems can be predicted at all, however, is absurd. …. Computers cannot accommodate such myriad variations. (MP).

It is strange then that science, relying heavily on computers, has achieved such success in fields such as genetics or mapping the human genome, with complexities and random or unpredictable elements (mutations) that arguably dwarf those of climate systems. The point is that one does not need to explain or predict the infinite complexity of everything in order to achieve useful results that can be accepted with confidence in the understanding, diagnosis and treatment of human genetic conditions. The same is true of climate science.

Conclusions

We can generally observe on this side of the climate debate, a high degree of sophistry, the use of clever but false arguments intended to deceive, together with a cavalier attitude towards evidence. This is not exactly unknown in the world of politics, but in relation to existential threats such as climate change it has an almost unique degree of irresponsibility.  If it is ideologically inspired, as many suspect, we would do well to ponder the example of the Soviet geneticist Lysenko, whose ridiculous but politically driven theories on the genetics of wheat resulted in mass starvation in the 1930s.

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[1] The science has been “… yet another variation of Leftwing, anti-American, anti-West ideology which goes hand in hand with anti-globalisation and the belief that everything done by the industrialised world is wicked”, according to Melanie Phillips; Daily Mail, 12 January 2004.

[2] There is however a remarkable correlation between denial of the science, support for Brexit, and ideological opposition to any state or inter-governmental interventions of the kind that any action to limit GHGs implies. But again the demonstration of this kind of motivation is not part of any scientific argument, although it has serious and disturbing political implications.

[3] As observed in the immediately previous posting. CLIMATE CRISIS. TRUSTING THE SCIENCE HAS NEVER BEEN MORE IMPORTANT.

[4] There is for example no evidence that the so-called “mediaeval warm period” was significantly different in global temperature from the second half of the twentieth century. But we shall never know.

[5] !980 is chosen in this context only as an approximate date for the development of widespread scientific concern over global temperature and GHG trends

[6]On a long term perspective it is the melting of land ice that is much more serious in contributing to sea level rise. 

And, finally, to avoid the accusation of selective misquotation, here is a fuller extract from the Melanie Phillips article:

Trump is being accused of being anti-science. On the contrary: it’s the anthropogenic global warming (AGW) scam that’s anti-science. Here are some elementary facts.

• Observable fluctuations in global temperature are within the normal historic pattern of atmospheric variation. The world has always warmed and cooled; the climate changes continually and, at times, quite rapidly.
• From 1860 to 1875 temperatures rose, then decreased from 1875 to 1890, rose until 1903, fell until 1918, rose dramatically until 1941, then cooled until 1976.
• Historically, temperature increases have often preceded high CO2 levels, destroying this theory of cause and effect. Moreover, there have been periods when atmospheric CO2 levels were as much as 16 times what they are now, periods characterised not by warming but by glaciation.
• The warming that was observed between 1978-1998 has stopped and global temperatures have plateaued. This disproves the entire theory that carbon emissions – which have been rising – inexorably drive up global temperature. Faced with the consequent contradiction in the IPCC prediction of an 0.3°C global average temperature rise over a decade, AGW proponents claimed that the prediction allowed for pauses. It didn’t.

• The seas are not generally rising any more than they have done for thousands of years.

• The icecaps are not generally melting; Antarctic ice is actually increasing.

• The polar bears are not dying out but increasing in number.
• There is no upward trend in the occurrence of virtually any extreme events such as tornados, hurricanes, droughts or floods, and some are in fact decreasing.
• Predictions of planetary temperature apocalypse derive from computer modelling.

The assumption that highly complex natural systems can be predicted at all, however, is absurd. And climate change is arguably the most complex system there is: coupled, non-linear, chaotic. The number of feedback mechanisms involved is vast. Computers cannot accommodate such myriad variations.

CLIMATE CRISIS. TRUSTING THE SCIENCE HAS NEVER BEEN MORE IMPORTANT.

What do Scientists Really Know? Why the Philosophy Really Matters.

This column does not often stray into the philosophy of science, but there are occasions when it is useful to reflect on just why we consider certain things to be true and with what evidence. Nowhere is this more true than in evaluation of what science tells us on climate change. Given the superficial and inaccurate material that continues to flow from the many political opponents of action on climate issues, it is worth dissecting some of the fallacies and misunderstandings that find their way into popular debate. One of these is the notion that the nature of scientific knowledge is always provisional, with the additional assertion that it cannot therefore be relied upon in matters of policy. This is a misreading of the nature of scientific method and the philosophy of science. It is often combined with the false claim that climate science has lacked predictive power and in particular failed to anticipate the actual warming that we are now observing. These arguments owe little to logic or fact.

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“Science is never settled. History tells us that!”

“We can’t even find models that forecast tomorrow’s weather, so there cannot be any basis for predicting the climate decades ahead.”

A lot of the popular discussion on climate (and other) science stems from low level interpretations of the work of Karl Popper, and in particular the criterion of falsifiability as a necessary condition for any proposition to be considered as science. So it is worth describing briefly the nature and status of Popper's philosophy. Loosely summarised, Popper's essential thesis was that no proposition could ever be finally proved, but that proper science could be defined by our ability to set tests, often of a predictive nature, for it to pass. Hence falsifiability, or the capability of being disproved, was the test of proper science. Popper has always been popular among political commentators, especially on the Right, because he usefully demolished the pretensions to science status of many Marxists. He observed that they failed, or refused, to produce testable, and hence falsifiable, propositions based on their ideas.

These ideas, taken in isolation, characterise science as proceeding by a series of hypotheses, each of which may or will in turn be falsified and replaced by a better  hypothesis. This is the feature that excites the interest of climate science sceptics. The idea (incorrect, as we shall argue later) that scientific propositions are always provisional supposedly implies that they can and will be found to be false, and are therefore not reliable as a basis for policy. Needless to say, this is an attractive argument for anyone faced with what they may regard as an “inconvenient scientific truth”.

So far, so good. Popper made an important contribution, at the very least as a codification of what had always been present in de facto practice of science since the days of Isaac Newton[1]. But his insight is not the whole story, although it is sometimes treated as such in a political context. Nor is it a complete description of how science works, and Popper is certainly not the ultimate court of appeal or the last word on scientific method.

One excellent source on this subject is the work[2] of Brian Davies, referenced below, which gives a much more coherent and comprehensive account of the nature of proof and knowledge in mathematics and science, fully acknowledging the contribution of Popper among others, but putting it in its proper historical, scientific and philosophical perspective. Another interesting article by Richard Lawson[3] makes a further interesting contribution on the application of Popper’s approach to validation of climate science

Popper and Evolution. Scientific understanding of evolution has had an enormous impact on human thought and on practical science since these ideas developed more than 150 years ago. Comparison with climate science, which threatens to be an issue of similar scale, is therefore instructive, not least because there is some overlap[4] between the sceptics on both issues. However, Popper’s judgement on matters scientific is called into question by his earlier failure to recognise the theory of evolution as science under his criterion. JBS Haldane is famously attributed the answer: “Show me a pre-Cambrian rabbit, and my confidence in the theory of evolution is lost.” Popper later and sensibly retracted.

Not all science provides a basis for future prediction. Falsifiability does not depend on and cannot be equated with the ability to make accurate future predictions. Evolutionary biologists may understand perfectly the mechanisms of genetic mutation but there is no way they can predict, or we test, exactly how random mutations might lead over many millennia to the evolution of new species under the same or changed environmental conditions. Similarly, weather, the day-to-day manifestation of climate, is intrinsically unpredictable for more than a few days ahead. But this is much less likely to be true of climate, the composite or “average” of weather over a long period.

Prediction and falsifiability. The reality of science is in practice much more nuanced and complex than a simple move from predictive failure[5] to falsification. Where a prediction made from an apparently well-established theory fails, the first response should normally be to look for what has gone wrong with the data or the experiment, or what other factors have affected the result. It should not be immediate rejection of a well-established theory.  Otherwise the laws of chemistry and physics would be disproved on a daily basis in school laboratories.

At a higher level, discrepancies in the orbit of Uranus revealed the existence of Neptune, not the failure of Newton’s Laws. Small discrepancies for Mercury, on the other hand, could only be explained after Einstein’s theory of relativity had overtaken Newtonian physics as a more complete description of the universe. The clear parallels in climate science have been critical examination of apparent anomalies in global temperature data (compared to model predictions), together with the impact of unpredictable events such as particular large volcanic eruptions. The normal scientific process of seeking increased understanding has, in this context, absurdly been characterised as data fraud, as part of the politicisation of the policy debates. Perhaps fortunately for Einstein and the general theory of relativity, views on the orbit of Uranus did not disturb as many vested interests.

Science may never be complete, but it is not always provisional. The absence of complete knowledge and understanding does not imply the absence of useful knowledge and understanding. Most of conventional science is for all practical purposes providing facts that we can and do treat as certain. Our understanding, even of the principles of quantum physics, and however incomplete, enables most of the advanced technologies of the modern world that we take for granted.

Popper’s characterisation of scientific knowledge as always provisional, is more relevant to particular parts of physics (quantum mechanics or astrophysics) than it is to many other sciences.  Theoretical physics does indeed include speculative interpretations, such as string theory or parallel universes (though it is questionable whether either is capable of being tested and meeting Popper’s falsifiability test). But much of science, especially in relation to the natural world, is descriptive and observational.

Science gives us a huge amount of fact that is certain. There are many more things that we “know” with certainty as a result of scientific observation, that do not need to be regarded as “provisional”, and are fundamental to any sensible consideration of public policy. This is true of much of climate science, which will be essentially concerned with careful observation of known phenomena such as parts of the carbon cycle or heat exchange within the oceans and the atmosphere.

 “Science is never settled. History tells us that! “

This is an absurd generalisation and history tell us nothing of the kind. Science provides vast amounts of knowledge that we can and do, for all practical purposes, treat as certainty. We know that the basic theory of tectonic plates is true. We know that AIDS is caused by the HIV virus, and malaria by mosquitoes. We know that mass vaccination can protect populations from lethal diseases.

The anti-science brigade, from the Trump and Pence core vote on measles, or tobacco companies denying the links between smoking and lung cancer, or Melanie Phillips on MMR vaccines, or African leaders in denial on HIV/AIDs, and more recently anti-vaccination activists on Ebola, must over the years bear responsibility for huge amounts of human suffering.

The basic building blocks of climate science, in terms of the radiative forcing effects of various greenhouse gases, have well established parameters, and we have, at a minimum, an awareness of most of the other major factors involved in the carbon cycle and the climate system. And the knowledge is constantly improving. Climate science as a distinct discipline consists of the application of knowledge from a large number of separate but related fields of knowledge and observation. Putting the pieces together to form a full understanding of climate variation is a complex application of known science along with some known uncertainties. And of course it necessarily includes numerous year-on-year effects such as variations in solar variation and climate cycles such as el Nino, which do not have a human cause, as well as the possibility of sampling error in climate measurement.

 “We can’t even find models that forecast tomorrow’s weather, so there cannot be any basis for predicting the climate decades ahead.”

This is a popular myth with no basis in reality. Today’s short term weather forecasting, along with associated probabilities, is good enough to be extremely useful. In farming and shipping, not to mention storm alerts, it is regarded as a crucially important service. Forecasts will always have a margin of error, and will always be revised to reflect additional information and unforeseen extraneous factors, but in various forms it is an essential part of almost every human endeavour. 

The reality is that scientists have also proved remarkably consistent in their assessment of the determinants of climate, which is necessarily measured over much longer time scales than weather. This includes the global temperature impacts of greenhouse gases. These forecasting efforts are very well summarised in a Carbon Brief article that starts with some relatively simple calculations in the early 1970s.

In a paper published in Nature in 1972, Sawyer hypothesised that atmospheric CO₂ would increase by 25% and that the world would warm 0.6^oC between 1969 and 2000. Sawyer argued for a climate sensitivity – how much long-term warming will occur per doubling of atmospheric CO₂ levels – of 2.4^oC, which is not too far off the best estimate of 3^oC used by the Intergovernmental Panel on Climate Change (IPCC) today, on the basis of much more information and sophisticated analysis.

In some instances, the forecasts have under or overestimated current observed warming because they were based on assumptions that under or over overestimated key parameters such as CO₂ emissions, and other factors such as unusual volcanic activity. But of course the real purpose of forecasts is not absolute precision but a reasonably accurate picture, including the risks and uncertainties, of the impact of policy alternatives, such as the effect of allowing uncontrolled emissions or adopting measures for their limitation.

Rejection of known science is both foolish and unjustified. It has also become perhaps the most dangerous intellectual fallacy of our age.

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[1] Popper had never read Principia Mathematica. Had he done so he might have found Newton’s ideas on science closer to his own.

[2] Science in the Looking Glass: What Do Scientists Really Know? E. Brian Davies Oxford University Press, 2003. 288 pages, ISBN 0198525435. (Useful review in Notices of the American Mathematical Society.) Inter alia this remarkable book provides a good description of Popperian ideas on falsifiability, both their positive contribution and their limitations.

[3] Climate Science and Falsifiability. Philosophy Now, 2014. Richard Lawson shows how Karl Popper can help settle the climate debate. This article by Richard Lawson provides a usefully brief discussion and turns the sceptic argument on its head by imposing a falsifiability test on the sceptic position.

[4] Christopher Booker. Trump and Pence.

[5] It is of course only in very specific conditions, such as astronomical observation or highly controlled laboratory experiments, that truly precise predictions and measurements are relevant. In most practical circumstances outcomes can be significantly affected by complex boundary conditions, eg the precise shape of the land mass and its contours.

NORWAY’S DISINVESTMENT IN OIL, THE GREEN PARADOX, AND A WEAKNESS OF POLICY TOWARDS GLOBAL CLIMATE RISKS

This commentary was provoked by recent reports that Norway’s sovereign wealth fund is to sell off its investments in companies that explore for oil and natural gas. This has been welcomed by some environmentalists campaigning for disinvestment from the hydrocarbon-based economy. In fact the Norwegian move is not really a signal of environmental virtue or ethical investing, and is best interpreted simply as a prudent rebalancing of their investment portfolio, a point made forcefully by Nick Butler in a recent FT article (18 March 2019). Butler regrets that this disinvestment is not balanced by “positive” investment in low carbon alternatives.

Butler goes on to claim, again correctly, that environmentalists may also be disappointed because, as he says, the evidence is that the oil companies are anticipating a continuing demand for their product, with few forecasts anticipating a peak before the mid-2030s. If these forecasts are correct and we are unable to prevent continuing growth in production and consumption, then it is bad news for hopes that the ambitious aspirations of the Paris agreement can be met, and that global warming can be limited to the 1.5^o C. This is regarded by many climate scientists as the upper limit consistent with avoiding the most dangerous environmental and climate outcomes.

There are however some related factors that should concern us in relation to oil industry incentives for investment. One is the so-called Green Paradox[1]. This argues, very logically, that if fossil fuel producers perceive that they face increasingly hostile restrictions on output, and gradually increasing carbon taxes, then they have a strong incentive to accelerate production and accelerate the depletion of their reserves. Implicitly the same argument would apply to many of the main sources of demand for oil, where the product depends on oil consumption either in the production stage

And yet that is more or less exactly the future carbon scenario that is most often presented in policy forums, that of a gradually increasing carbon tax. Needless to say, there is little evidence yet of the sort of collapsing investment that would seriously reduce supplies, nor of the much higher oil prices that could result, at least temporarily, from serious disincentives to production. The oil price seems to be stuck somewhere around the $60/ bbl mark, near the bottom of the $60 - $120 “credible range” recognised by many industry analysts.

In consequence it should be no surprise that production and consumption continue to rise. A rational policy to reverse this, and to overcome the Green Paradox, would be to recognise that, if anything, immediate near-term emissions, given that CO2 is cumulative, do more damage per tonne than future emissions[2] and have a significantly higher social cost. Rational policy towards climate should therefore include a policy for a price/tax on emissions that starts high rather than climbs gradually. This would make fossil fuel extraction and investment less profitable, and also provide an additional non-distorting incentive for low carbon investment of all kinds, an objective that many of us share.

Of course, it will be argued that this may have redistributive consequences, but green taxes offer their own answer in this respect. Revenues from taxing emissions offset the need for other taxes, or can be used for redistributive agendas.

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From an economic analysis perspective, the Green/ Sinn Paradox may not seem very surprising. It simply represents a potential consequence of policies that are poorly thought out (at least from a climate perspective). There are of course other factors that lead some oil rich states to favour accelerated exploitation, notably the desire for an immediate boost to the domestic economy, even at the expense of longer term considerations. But the Sinn paradox provides an additional incentive.

The source of the disconnection, between the science led climate imperative and the current economics of fossil fuel industries, is explored in more depth on another page: CUMULATIVE CARBON. HAS THE ECONOMICS LOST CONTACT WITH THE PHYSICS?

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[1] aka the Sinn paradox, it was first discussed by Hans Werner Sinn.

[2] See link above.

CLIMATE CHANGE. CREATION OF THE “PERFECT STORM”. WE WERE WARNED.

On this day …. Sometimes anniversary events can underline and dramatise a sombre warning.

19 March 2009. BBC

John Beddington, then Chief Scientific Adviser to the UK Government, warned the Sustainable Development UK 09 conference of a global crisis 'to strike by 2030'.  Growing world population would cause a "perfect storm" of food, energy and water shortages by 2030. "It's a perfect storm."  (Link)

“There is an intrinsic link between the challenge we face to ensure food security through the 21st century and other global issues, most notably climate change, population growth and the need to sustainably manage the world’s rapidly growing demand for energy and water. It is predicted that by 2030 the world will need to produce 50 per cent more food and energy, together with 30 per cent more available fresh water, whilst mitigating and adapting to climate change. This threatens to create a ‘perfect storm’ of global events.

.….

The backdrop against which these demands must be met is one of rising global temperatures, impacting on water, food and ecosystems in all regions, and with extreme weather events becoming both more severe and more frequent.     Rising sea levels and flooding will hit hardest in the mega-deltas, which are important for food production, and will impact too on water quality for many.

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Even since the last report of the Intergovernmental Panel on Climate Change (IPCC) in 2007, new evidence suggests that climate change is impacting the real world faster than the models predicted, and global greenhouse gas emissions are continuing to rise at the high end of projections. For example, in 2007 the IPCC concluded that large parts of the Arctic were likely to be ice-free in the summer by the end of the 21st century. Record lows in sea ice extent in 2007 and 2008, combined with other evidence on ice thinning and age, have caused scientists to radically review these estimates, with some analyses now suggesting the Arctic may be near ice-free by 2030 (Figures 5 and 6).  This has major implications not just for the Arctic region but for the world as a whole, as strong positive feedbacks effects are expected to drive climate changes even faster.” Recall that this revision is being discussed in 2009.

19th March 2019, Guardian:

Cyclone Idai, now devastating large areas of South East Africa, 'might be Southern Hemisphere's worst such disaster'.

 Dr Friederike Otto, of Oxford University’s Environmental Change Institute, said: “There are three factors with storms like this: rainfall, storm surge and wind. Rainfall levels are on the increase because of climate change, and storm surges are more severe because of sea level rises… Otto said it was important to help communities in the worst-hit areas become more resilient to storms. “The standard of housing, the size of the population and effectiveness of the early warning systems … these are the sorts of things we need to think about as we move into a world where these events become more severe.”

We are now starting to see the real human impact of our collective failures to heed the warnings. The trend line, and the inertia built into our limited responses, suggests our problems may just be beginning.

Climate scientists, far from alarmist, have tended to understate the risks. Even in 2009, projections of Arctic ice melt were being revised upwards.

• This is no longer a remote and uncertain risk. It is an existential threat.
• In ten years, we have made nothing like sufficient progress to mitigate or adapt to the dangers we face. 
• There is still a large constituency of political leaders, economists and commentators, that is in complete denial on the subject.  (Lawson, Mogg, Trump, Redwood, Phillips …).

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BRAIN OF BRITAIN QUESTION. What else do those last named have in common?

ANSWER. They have all been enthusiastic advocates of Brexit. EIGHT ECONOMISTS. BREXIT AND CLIMATE

A GRAPHIC ILLUSTRATION OF CLIMATE CHANGE

Antti Lipponen of the Finnish Meteorological Institute has created an animated chart that shows the trend in global and national temperatures from 1900 to 2017, ie almost to the present day. The distinctive feature is that it shows how an overall trend, significant in itself, can mask even more dramatic swings in individual geographies and in variations between them. Some though not all of these are likely to be experienced as episodes of unusual or extreme weather, eg drought or flood.

It is expressed in terms of temperature anomalies, or deviations from the norm. In this case this just means deviation from the average over the period 1951-1980.
To interpret what is happening in more detail, the following is a useful key
Year. In the centre of the circle is the year of the observations, starting in 1900.
Global temperature trend: top right of the picture.
Temperature anomalies.   Moving out from the centre are five concentric rings, corresponding to the size of the anomaly: from – 2.0^oC through –1.0^oC, 0.0^oC, +1.0^oC, to +2.0^oC. Individual country values are expresses as spokes emanating from the centre, with colours expressing the scale of the deviations, (negative = blue, positive = red)
Geography. The individual countries should be visible in full screen mode, but for a quick impression of what is happening in global differences, note that the quadrants can be summarised as follows. Moving clockwise from 12.00, we find:

Top right; Asia and the Middle East
Bottom right: Africa
Bottom left: Europe
Top left: The Americas and Oceania

The animation has the virtue of demonstrating in visual form the potential significance of global warming in provoking increasing numbers of extremes, which may nevertheless vary substantially from year to year, country to country, and continent to continent.

CLIMATE SCIENCE. RESIDUAL UNCERTAINTIES THAT DO NOT CHANGE THE UNDERLYING MESSAGE.

Understanding Time Lags Important for Climate Policies.

“Cumulative carbon”, the fact that human emissions of CO₂ are removed only slowly from the atmosphere through the natural carbon cycle, is the essence of the climate change problem. Given the thermal inertia of our planet it may produce a substantial time lag between effective action, to limit emissions, and actual stabilisation of temperatures, equivalent to the operation of a domestic heating radiator on a one way ratchet. Some climate scientists believe this effect may have been exaggerated, and will be largely offset by other elements in the natural cycle. Even so there is a consensus that we need to move to a world of net zero emissions and beyond.

So much of the predictive element of climate science has been borne out by observation that it is easy to forget there are still major gaps in our understanding and major uncertainties that are very relevant to understanding what climate policies are necessary to (ultimately) stabilise global temperatures.

The slow but seemingly relentless upward trend in global surface temperatures sits firmly in the middle of past model predictions, and denials that it is actually happening (the famous Lawson “hiatus” based on cherry picking outlier el Nino effects), or that it has nothing to do with human contributions to greenhouse gas concentrations, look increasingly threadbare and ridiculous. There is no doubt that human-induced climate change is with us, and that it is dangerous.

However, although the science makes it clear that urgent emission reductions are essential, it is much less clear how much leeway we have, and whether the 1.5^o C or 2.0^o C “targets” are attainable. The uncertainties manifest themselves in discussions over the time lags involved, for example between stabilisation of the atmospheric concentration levels of CO2 and stabilisation of global temperature. These questions relate in turn to complexities of the natural carbon cycle and the

The issue of time lags is in some ways politically important. Thomas Stocker, then co-chairman of the IPCC Working Group I (assessing scientific aspects of the climate system and climate change), and addressing the Environmental Change Institute in Oxford in 2014, argued that “committed peak warming rises 3 to 8 times faster than observed warming”. The implication is that there are very substantial time lags. In this case temperatures could continue to rise, perhaps for several decades or even centuries, even if net human emissions were reduced to zero. Similar comments can be found from other climate scientists. It has even been suggested that the thermal inertia effect, considered on its own, could stretch the lag to about 200 years – the time for heat equilibrium adjustment to reach the deep oceans.

The intuitive physical explanation of long time lags is simply the phenomenon of thermal inertia. When we turn up the radiator at home it may take an hour or more for the room to reach a new equilibrium temperature. Global warming, in this analogy, is a radiator heating system on an upward ratchet. The issue for humanity is that by the time temperatures become really uncomfortable, we have already ratcheted up the future temperature to which we have committed. If this is a real danger it dramatically increases the risks associated with climate inaction or “business as usual” trends. It is also creates an alarming image of climate change as a kind of doomsday machine in which humanity is trapped through its failure to anticipate and respond.

However rather more optimistic views have been presented by other scientists. In 2014 Ricke and Caldeira[1] argued that the lags had been seriously overstated, suggesting a time lag of only ten years as a more appropriate estimate. Oxford-based climate scientists, such as Myles Allen, have also suggested that stabilising atmospheric concentrations could lead to a comparatively early stabilisation of global temperature.

The main reason is the potential offsetting effect of the absorption of incremental carbon through the various elements of the natural carbon cycle, including ocean CO₂ uptake and the behaviour of biosphere carbon sinks. However there is no natural law that requires such a balance of effects, and the reality seems to be that we are trying to compare two magnitudes, both of which are of major importance but are also difficult to measure with precision. If the effects broadly cancel out over particular timescales, this is essentially a numerical coincidence within the modelling effort. We can expect future research, better measurement, and associated modelling, will gradually improve our understanding.

But melting ice caps are a separate story!

The above discussion does not however cover all the long time lags involved. One particular concern has to be the polar ice caps. If global temperatures reach the point where these start to melt, then the consequential effects in the form of rising sea levels will go on for centuries. Ice sheets, as opposed to sea ice, can, like the retreating glaciers, only be restored by precipitation. That will be slow and net annual ice gain will probably depend on conditions associated with a fall in global and polar temperatures to or beyond what used to be regarded as normal.

And the policy implications of these uncertainties?

In reality the consequences for policy of differing estimates can be exaggerated, since there is agreement on most fundamentals. Most modelling now recognises that stabilisation of temperature, even at a higher level, requires progress to net zero human emissions. Importantly, this is probably unachievable without substantial measures to remove CO2 (and other gases) from the atmosphere.  In practice processes for carbon sequestration are likely to be very expensive process. They represent a form of geo-engineering.

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[1]Maximum warming occurs about one decade after a carbon dioxide emission. 2014, Ricke and Caldeira