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.

LABOUR TO RENATIONALISE NATIONAL GRID? WE NEED BETTER ARGUMENTS AND MORE COMPREHENSIVE SOLUTIONS.

There is a good case for more central direction and control for the power sector but many of  Labour’s proposals are either muddled or counter-productive.

The Labour Party is talking about plans to renationalise the Grid. The UK power sector certainly has some major problems. The utilities themselves, and current market arrangements, are neither popular with the public nor particularly effective in delivering on key policy objectives, especially on reducing the UK carbon footprint.  The institutions of the sector do indeed need a serious overhaul, but the emphasis of Labour proposals distracts from more fundamental issues that surround the difficult task of decarbonising the UK economy, and overcoming the failings of the liberalised electricity market. We need a better discussion.

The Labour party has unveiled plans to take the National Grid back into public ownership, with the stated intention of providing a correction to alleged excesses of asset stripping and profiteering at the consumers’ expense, and making the power sector more responsive to social and environmental objectives. One headline grabbing feature of the proposals has been to suggest that shareholders would receive less than full market value in compensation. Another important component has been proposals to assist poorer households with the installation of solar panels, simultaneously enabling them to cut their electricity bills and reduce overall power sector emissions of CO₂.

The background is that National Grid is responsible for the nationwide transmission network, and transmission per se only accounts for around 10% or less of consumer bills. However, the Labour proposals extend to the much larger distribution networks and the aggregate of all the “wires” business is much larger, amounting to around 30% or more of domestic consumer bills. The tariffs that pass on these network costs to suppliers and consumers are regulated by OFGEM. The regulator’s main remit is to allow the network companies to make a fair, but not excessive return, on their assets, while at the same time encouraging efficiency and ensuring a high quality service.

Excess profits? If this is a problem it is easily cured within the existing regulatory framework.

OFGEM is a technically competent body and has 30 years experience in regulating tariffs. So, although private companies may always be seeking to outwit the regulatory regime and squeeze a little extra revenue, it would be surprising if large excess profits were a major issue[1]. If this were so, it should be a comparatively easy matter to tighten OFGEM’s regulatory regime. It’s also worth noting that the original 1990 privatisation is generally considered to have brought down network costs, although this was not the biggest source of cost reductions[2] for the sector as a whole.  The structure of the tariffs through which these costs are recovered is also an important but separate separate matter and one which we address briefly below.

National Grid currently discharges its main functions very competently, so proposals appearing to punish this part of the power industry may seem perverse and unnecessary. Proposals to confiscate part of the value of what are already closely regulated assets are particularly dangerous. If pursued, this could undermine the financial standing and credibility of the entire sector, as well as the borrowing capability of government itself. A serious unintended consequence would be to deter investment in the UK power sector. Raising the cost of either private or public capital, not just for the grid but for the whole sector, would make it harder for an increasingly capital intensive sector to maintain supplies to consumers at an affordable price.

Labour has also ignored some of the manifest weaknesses in supply competition[3], which in many respects is a more obvious failure to serve the consumer effectively.  It is far from clear that competition has been of any net benefit to consumers as a whole. The supply function per se adds little in the way of value, but supply margins have increased significantly^[4] while there is little or no differentiation in the quality of service that suppliers provide, little or no innovation in tariffs, and consumer prices have to cover the additional marketing costs incurred by the supply companies.

There is however a very strong case, as Labour suggests, for using the grid and network companies as part of an intervention to promote environmental and low carbon policies.

There are good reasons for concern that markets as currently organised have some manifest failings in relation to environmental objectives. These are described in more depth on the Low Carbon Power page, but the main considerations are the following.

1.    There is a need to support investment that is a necessary component of decarbonisation strategy but cannot be delivered by the private sector in a market environment that continues to under-price the true environmental and social costs of CO₂ emissions. A National Grid charged with an obligation to deliver national low carbon objectives could provide the mechanism and the expertise to remedy this. At present all low carbon generation investment depends on government support (through feed in tariffs or long term contracts) but government lacks the expertise to do this effectively.

2.    The need for coordination of choices made in transmission and generation investment is greatly increased in systems based on renewable or low carbon investment, in order to balance types of generation with different operating characteristics, storage and demand side response from consumers. An interesting illustration is the need for diversity in contracting for offshore wind power. Capacity auctions will most likely induce bids from the  most obviously attractive sites in terms of cost and output (site conditions and available wind), but solutions that work best will depend on selection of a diversity of sites that are not closely correlated in terms of weather. Market structures will not easily resolve these choices, but the Grid is ideally positioned to do so.

3.    Current consumer tariffs are quite dysfunctional in failing to provide the right economic incentives for low carbon. They fail to reflect incremental costs in ways which can penalise low carbon initiatives for consumers (such as domestic heat pumps) and arguably over-incentivise other forms of consumer investment, including solar. Getting the right economic signals in tariffs is particularly important in a future in which we envisage a much bigger role for various forms of decentralised energy provision. These arguments are discussed more fully in a recent blog[5] and report[6] commissioned by Energy Systems Catapult, but one possible resolution could be based on the transfer of supply responsibilities to the local distribution companies, who would have a much more explicit duty to encourage decarbonisation of the sector, very much in line with Labour’s stated objectives.

The essential point is that the National Grid, and the other network companies, will need to play a vital role in resolving these issues. Nationalisation need not be the only means to that end, with alternatives including the mandating of low carbon targets, or new statutory duties. But significant policy direction, and significant government support for low carbon investment, are likely to be essential components of any solution.

Labour is failing to make its case well

Labour has so far failed to make the comprehensive case that can be made for a more powerful National Grid, or for reform of the distribution and supply of power.  It has instead chosen to focus on greatly expanding the use of solar panels. This may please the solar lobby, and could indeed be part of a sensible overall strategy for the sector, but it is prima facie questionable to risk over-promoting solar power.  For the UK at least, solar power is counter- seasonal.  Solar output is highest in summer, but energy demand is highest in winter. This implies difficult technical judgements that an organisation like the Grid is better placed to make than either politicians or civil servants.

There are some strong arguments that opposition parties should be making, but they do need to do some better technical analysis, and avoid simplistic solutions that look attractive but fail to address the real problems.

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[1] The structure of the tariffs through which these costs are recovered is a separate matter and one which we start to address later.

[2] Much more significant was the move away from British coal, towards coal imports and later towards gas as an alternative fuel. The second factor was in part coincidental with the rise of new technology in the form of combined cycle gas turbines.

[3] These were extensively criticised in the 2012 IPPR report,  The true cost of energy: How competition and efficiency in the energy supply market impact on consumers' bills. Much of this analysis remains valid.

[4] The Monopolies and Mergers Commission report on Scottish Hydro in 1994, before introduction of competition in energy supply, considered that 0.5 per cent was an adequate margin for regulated energy supply. Recent margins have been as much as 4.0% or higher.

[5] THE ROLE OF TARIFFS IN A LOW CARBON FUTURE

[6] Cost reflective pricing in energy networks

DECLARING A CLIMATE EMERGENCY IS FINE. BUT WHAT SHOULD THE ACTION AND POLICY PRIORITIES BE?

The UK Parliament has responded to a recent raising of awareness on climate change by declaring a climate emergency.  This is unequivocally a positive sign for anyone concerned with our future wellbeing and species survival, but it leaves a lot of questions unanswered, not least on how to select priorities for effective policies. Here are a few thoughts.

This is a global not a national crisis.

Anything the UK can achieve, given it is responsible for less than 2% of global emissions, will only be meaningful if it has a wider impact and is set within a context of international cooperation and agreement. Any policies seeking a global reach will also, inevitably and inextricably be bound up with trade. There is for example no gain from simply exporting UK emissions to other places. The UK can achieve little on its own, and it is hard to see how we on our own would have any significant influence on China, India, or the USA, particularly a USA under a President who regards climate science as a hoax.  

Unsurprisingly, those most hostile to effective action on emissions, like Trump and our own home-grown Brexit gang, are also those most hostile to the EU. EU policies on emissions are admittedly far from ideal, and need substantial strengthening and reform; but it would be far easier for the UK to influence these from within by remaining a member of the EU. For the most part, other EU states and their populations at least share the same broad objectives.

The EU emissions trading scheme is not perfect and needs substantial tightening, but if it can be made consistent with the right climate objectives and targets, then continued participation is in the UK’s economic interest and will assist our own decarbonisation.

We need the closest possible cooperation with our nearest neighbours in the EU. Resolving the chaos and confusion of our current position, and preferably remaining within the EU, must also rank as a first priority for effective action on climate. Participation in a reformed EU trading scheme will make our own measures less costly.

There is a big premium on early rather than delayed action.

Sometimes the case is made for postponing action while time is spent researching better solutions. But the reality is that early reductions in greenhouse gas emissions (GHG), and especially CO₂, confer a large benefit and have a big option value in postponing climate milestones. This trumps the risk that we might occasionally choose less than perfect solutions when new technologies may be available further down the road. The benefits of early action are generally under recognised.

Front end loading of any emissions reduction strategy helps postpone critical climate milestones. This factor alone justifies the emergency tag. We should  start with the low hanging fruit, the easy wins that can be achieved, not at zero cost or without any pain, but without major infrastructure spending or excessive disruption to current lifestyles

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There are a few relatively low cost “wins” that do not depend on massive infrastructure investment, but relate more to behaviour, lifestyle choices and a few habits and customs. These may be partly attained through personal choices, but they are also susceptible to economic pressures and broader policies.  Two behavioural factors with major impact on GHG emissions are the very rapid growth in aviation and the consumption of meat in our diets. A third is the extent of speed and traffic congestion, two of the major factors that raise road transport emissions

Work towards international agreement on taxation of aviation fuel.

Environmental costs are largely priced into road transport fuels, at least in Europe, but not into aviation. There is a degree[1] of economic distortion here – absurdly, the fuel cost of a two people using their car to travel a thousand miles in Europe may be twice as much as two airfares, even though it gives rise to less than half the emissions. More importantly ultra-low airfares encourage very high carbon-intensive lifestyles, such as weekly commutes to distant weekend cottages, transatlantic stag weekends or Christmas shopping expeditions. This is a significant source of GHG driven by a tax anomaly. Some of these considerations also apply to the treatment of fuel for shipping.

With aviation as one of the fastest growing sources of GHG emissions, and the absence of an immediately available technology solution (electric aircraft), this must be an obvious priority if we are serious about the issue. As a measure it has an international impact, but of course depends on international agreement, although coverage of flights within Europe could be an important start.

Less meat eating.

Complete abandonment of meat in diets may not be a realistic goal, but even modest reductions could achieve significant reductions in GHG emissions associated with livestock rearing. Eating less meat in many Western economies has significant health benefits, and is a lifestyle trend that is already gaining ground. It is also consistent with a more sustainable approach to agriculture and land use, a reminder that CO₂ is not the only problem of environmental degradation that we face.

Managing road traffic; reducing both speeds and congestion.

Speed and congestion, as every motorist with a trip meter will know, are both major sources of extra fuel consumption that are to a significant degree within our individual and collective control. Lower speeds lead to significant reductions in fuel consumption, and so do measures, like road pricing, designed to curb urban congestion. Once again these are measures that can bring health, safety and general environmental benefits.

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Behavioural changes only take us so far.  Eating less meat, taking fewer flights and turning down the heating to 19^oC will not get emissions anywhere near the ultimate target of zero. We are ultimately dependent on making changes that depend on large scale infrastructure investment, especially in relation to power and heat. So as well as making the relatively easy emissions savings we need to turn our attention to a wide range of actions required to prepare for substantial infrastructure development.

My priorities[2] on this include

• Much more coherent direction of the power sector towards earlier achievement of very low emissions targets.
• Re-establishing support for carbon capture and storage, and other low carbon options in generation.
• Infrastructure that enables rapid transformation towards electric vehicles (EVs)
• Much clearer policies for heat, and promotion of early trials of local heat networks, as well as other routes to low carbon such as electric heat pumps.

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[1] Obviously travel time may be a bigger factor than cost for many people, but relative costs will also influence travel choices as between road, rail and air.

[2] Some of these broader policy questions are discusses elsewhere on this site, including the pages: Decarbonising Heat, Low Carbon Power, and A Climate Manifesto. (bar at top of this page)

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.