Friday, May 3, 2019


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. 
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.

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.

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

1 comment:

Anonymous said...

I notice that MP talks about chaos. It is important not to confuse chaos with complexity, randomness or unpredictability. For example one of the moons of Saturn, Hyperion, has chaotic rotation in the proper technical sense although it moves in full accordance with Newton's laws, which are deterministic. Chaotic is not the same as random or unpredictable and I would guess that genetic mutations should be called random. A highly simplified model of weather patterns were among the first examples of chaotic dynamics -- Lorenz 1961.

I also imagine that someone has written about the Milankovich laws governing the major ice ages and about the volcanic (?) cause of the Little Ice Age. Scientists should perhaps emphasize that they do know about natural causes of climate change and are taking such possibilities into account!