‘Anyone who thinks global warming has stopped has their head in the sand. The evidence is clear – the long-term trend in global temperatures is rising, and humans are largely responsible for this rise.’ (1) This emphatic statement from the UK Met Office yesterday is just the latest shot in the ‘climate war’. But in truth, the polarised and highly politicised nature of the current discussion on global warming features plenty of people on both sides with their heads firmly buried, using ‘science’ to disguise the real debate about the future political and economic direction of society.
This was neatly illustrated by a recent BBC TV series, Earth: The Climate Wars, which ended on Sunday. Last week’s episode, entitled ‘Fightback’ was a particularly one-sided attempt to undermine the critics of the orthodox position on global warming.
Iain Stewart, professor of geosciences communication at Plymouth University, introduced last week’s instalment with the words: ‘Global warming – the defining challenge of the twenty-first century.’ The programme examined the arguments made by the two putative ‘sides’ in the global warming debate, to show ‘how [the sceptic’s] positions have changed over time’. But Stewart misconstrued scepticism of the idea that ‘global warming is the defining issue of our time’ with scepticism of climate research. In this story, ‘the scientists’ occupied one camp (situated conveniently on the moral high ground) and the bad-minded, politically and financially motivated sceptics the other. But there was no nuance, no depth and no justice done to the debate in this unsophisticated tale, and it did nothing to help the audience understand the science.
‘At the start of the 1990s it seemed the world was united’, Stewart told us. World leaders were gathered at the Rio Summit to sign up to the United Nations Framework Convention on Climate Change (UNFCCC), the instrument that would pave the way for the Kyoto Protocol. He recalled the excitement felt by researchers at the prospect of the world being united by concern for the environment. ‘Even George Bush [Senior] was there. But the consensus didn’t last.’ Sceptics, it seems, are responsible, not just for the imminent end of the world, but also for corroding global unity.
Stewart’s intention was to show that ‘the scientific consensus’ existed prior to international agreements to prevent climate change. But the basis of the UNFCCC was not a consensus about scientific facts. It could not have been, because scientific facts about human influence on the climate did not exist in 1992, as is revealed by the Intergovernmental Panel on Climate Change (IPCC) First Assessment Report in 1990, which concluded that ‘The unequivocal detection of the enhanced greenhouse effect from observations is not likely for a decade or more.’ Even the second IPCC assessment report in 1995 did not provide the world with the certainty that Stewart claims: ‘Our ability to quantify the human influence on global climate is currently limited because the expected signal is still emerging from the noise of natural variability, and because there are uncertainties in key factors.’ (2)
Instead of consensus and certainty, the UNFCCC was driven by the precautionary principle. Principle 15 of the Rio declaration states: ‘In order to protect the environment, the precautionary approach shall be widely applied by States according to their capabilities. Where there are threats of serious or irreversible damage, lack of full scientific certainty shall not be used as a reason for postponing cost-effective measures to prevent environmental degradation.’
Omitting the role of the precautionary principle creates the idea that scientists have always known that industrial activity caused global warming. So, with the benefit of hindsight, Stewart could lump various objections to the interpretation of controversial evidence which existed at the time into one ‘sceptic’ category. Not according to the scientific substance of the argument, but according to whether the argument was later vindicated; not by the consistency of the argument with reality, but whether or not it ‘supported’ the theory of anthropogenic global warming (AGW).
In 1992, the data simply wasn’t available to conclude with any great confidence that global warming was happening. But by the logic of Stewart’s argument, as long as you were right about global warming being a ‘fact’ at that time – even if that meant in reality you were wrongly interpreting the evidence available – you were a ‘scientist’. But, if you were right about the unreliability of data in 1992, then you were wrong in 2001, because you were a ‘sceptic’. If this were just a debate within an academic discipline, such challenges would not have any major significance outside of it. But Stewart, like many others, takes routine and isolated differences of scientific opinion, and groups them to imbue them with political significance.
A warming world?
The first scientific debate Stewart presented concerned the reliability of data generated by compiling the records of tens of thousands of surface-based weather stations. Sceptics had argued that these installations were too sparsely distributed and data from them had been contaminated by urbanisation over the twentieth century. Stewart demonstrated that this is indeed a problem. He used the example of the temperature at Las Vegas Airport – home to a monitoring station and heavily urbanised since it was originally set up – and compared it with the temperature outside the city limits, which was markedly cooler. This suggests that making comparisons over time using data from many such stations, where the local environment has changed, may result in over-stating global warming.
The sceptics’ argument was seemingly corroborated in the 1990s by satellite data that showed a slight cooling trend over the 1980s. Ten years later, it turned out that the satellite data had been flawed, Stewart told us. The satellite’s orbits had been drifting downward, and the data they had produced improperly compiled. A correction to the data revealed a warming trend. ‘The sceptics had to admit the world was warming’, said Stewart.
But here again, we see an artefact of the retrospective polarisation of the ‘climate wars’. The truth was that both ‘sides’ were wrong while they had invested their confidence either in the surface station data or the satellite data; both sets of data were ‘wrong’ – Stewart had just demonstrated it himself. But the nuances of the debate don’t interest Stewart. ‘The scientists’ are vindicated by any evidence which shows that ‘the earth is warming’, regardless of its quality. The sceptics, on the other hand, are not vindicated for having pointed out that the surface station record was questionable.
The not-so jolly ‘hockey stick’
Stewart then examined the sceptic claim that an episode in Earth’s history known as the Medieval Warm Period (MWP) shows that current temperatures are not unprecedented in recent geological history. This was countered by climate researcher Michael Mann, who reconstructed past temperatures where no instrument data were available. By analysing ‘proxies’, such as tree-ring width, ice cores, and coral reefs, he produced a graph which apparently revealed that the MWP was not a global phenomenon, and showed current temperatures to be in excess of anything in the previous millennium.
Temperature reconstruction of past 1,000 years, showing difference between estimated temperature and the 1961-1990 average (IPCC, 2001)
‘Sceptics hated it’ announced Stewart. Indeed they did. Mann’s study remains highly controversial for good reasons. But Stewart gave no time to explaining the objection to these reconstructions, other than to characterise them as ‘personal attacks’ against Mann. The graphic had been the centrepiece of the IPCC’s 2001 Third Assessment Report, used to demonstrate the unequivocal influence of human activity on the climate.
Yet perhaps one of the reasons it was so prominent – in spite of criticism – is that Mann himself was a lead author on the chapter which featured it (3). The IPCC is understood to be a meta-review of the available literature on climate change, but allowing authors to review their own work represents something of a departure from the scientific process. In 2007, following continued criticism of Mann’s method, the IPCC were far more circumspect about the value of such reconstructions. Where Stewart presented these reconstructions as ‘proof’ of todays high temperatures, the IPCC give the statement that ‘twentieth century was the warmest in at least the past [1,300 years]’ just 66 per cent confidence (4).
Sceptical ‘guns for hire’
It is only Stewart’s binary treatment of the issue into true and false and ‘scientists’/’sceptics’ that allowed him to reach his conclusion: ‘There are a lot of people who don’t want global warming to be true’, he tells us. ‘Cutting back on greenhouse gases threatens the freedom of companies to go about their business.’ According to Stewart, companies used the media to emphasise the uncertainties in climate science for their own ends – profit – a cause and strategy taken up by the Bush administration.
This is an almost verbatim copy of an argument put forward by a prominent climate change advocate and science historian at the University of California, San Diego, Naomi Oreskes. She had claimed that the ‘climate change denial’ movement comprised the same individuals and network of organisations that had been instrumental in denying the link between smoking and cancer (5). By emphasising doubt and uncertainty in the claims of honest and decent scientists, Oreskes claims, ‘the tobacco strategy’ aimed to influence public opinion to secure the interests of oil and tobacco companies, and the political Right. It should be no surprise then, that Naomi Oreskes was credited on the first episode of the series.
Stewart’s and Oreskes’ conspiracy theories depend on reducing scientific arguments to meaningless factoids, and casting the debate as one between goodies and baddies. Nowhere is this more obvious than in the film’s closing moments. In order to demonstrate that ‘the sceptics’ had changed their arguments in the face of overwhelming scientific evidence, the film used footage from the Manhattan Conference on Climate Change earlier this year, a meeting that featured a large number of sceptical writers and researchers.
‘For years, climatologist Pat Michaels has been one of the most vocal sceptics. And yet, today, he’s in surprising agreement with the advocates of global warming’, said Stewart. Michaels is then shown giving his talk, saying ‘global warming is real, and in the second half of the twentieth century, humans had something to do with it’. But there is nothing surprising about Michael’s apparent turnaround, because it isn’t one. A 2002 article in the Journal of Climatic Research, authored by Michaels et al argued for a revision of the IPCC’s projections for the year 2100. Instead of saying that there would be no warming, the paper concluded that rises of ‘of 1.0 to 3.0 degrees Celsius, with a central value that averages 1.8 degrees Celsius’ were more likely than the IPCC’s range of 1.4 to 5.8 degrees Celsius (6). Hardly climate change denial.
What could have been an interesting film was instead a fiction. It attached fictional arguments to fictional interests to legitimise the politicisation of the debate – exactly what it accused the sceptics of. Rather than concentrating on the arguments that have actually been made, Stewart invented the sceptic’s argument to turn climate science into an arena for an exhausted political argument for ‘change’ that has failed to engage the public.
The real ‘climate war’ is between those who do not believe that our future is determined by the weather and those who think that ‘climate change is the defining challenge of our time’ and define themselves – and everybody else – accordingly. Don’t expect a documentary film about it any time soon.
(1) Global warming goes on, Met Office, 23 September 2008
(5) Watch Orekses’ lecture on The American Denial of Global Warming, Youtube
(6) Revised 21st century temperature projections, Michaels PJ et al, Climatic Research, Vol. 23: 1–9, 2002 (PDF)