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the real debate begins where the science ends

bergens tidende, 13 december 2009

On Monday, as the UN climate change conference opened in Copenhagen, 56 newspapers across the world (including Dagbladet in Norway and the Guardian in Britain) published a front page editorial. ‘The science is complex but the facts are clear’, it claimed. And ‘the facts have started to speak… In scientific journals the question is no longer whether humans are to blame, but how little time we have got left to limit the damage.’

This has become the mantra of the environmental movement, and indeed of the Copenhagen conference. Science has told us the facts. Now we must act. There can be no questioning the policy because it is backed by the authority of science.

It was an argument into which Mike Hulme, one of Britain’s leading climate scientists, once bought. In 1997, in the run-up to the Kyoto conference, he helped organize a statement by European climate scientists that supported the then EU position of a 15 per cent cut in CO2 emisions by 2010. ‘By signing it “European climate scientists”’, Hulme recalls, they hoped to create the impression that ‘our belief was a non-negotiable conclusion of our scientific work.’

Today, he says, he is ‘rather critical of my naivety 12 years ago.’ Not because he rejects the idea of man-made global warming. Nor because he does not believe in CO2 emission cuts. But because, he says, it was a strategy that dangerously blurred the lines between science and politics. ‘When science is invoked to support such dogmatic assertions’, he observes, ‘the essential character of scientific knowledge is lost – knowledge that results from open, always questioning, enquiry that, at best, can offer varying degrees of confidence about how the world is, or may, become.’

Hulme works at the University of East Anglia, the same university whose computers were hacked to steal emails from the Climactic Research Unit, emails that generated a storm of controversy in the run-up to Copenhagen. For many global warming skeptics, the emails reveal a worldwide conspiracy by climate scientists to cook the facts. For many supporters of the idea of global warming, they are an irrelevant distraction from the task of mitigating climate change. Both are wrong.

Nothing in the CRU emails undermines the scientific case that global warming is real, a trend indicated not just by temperature records but also by retreating glaciers, reductions in Arctic ice, melting permafrost, changing bird migration patterns, and the earlier arrival of spring. There is good evidence too that humans are at least partly responsible for this change through increased CO2 emissions. There is debate as to how much of climate change is down to human activity, and the degree to which CO2, as opposed to other greenhouse gasses, is responsible. The biggest questions, however, are not about the past or the present but about the future. By how much will atmospheric CO2 grow and what will be the consequences? And what should we do about this?

Climate scientists have built complex models to track the future growth of CO2 emissions and their consequences. Such models are often the weakest part of any scientific argument, not only because of their complexity but because, almost by definition, they employ assumptions that may be questionable. Such uncertainties are part and parcel of science and would normally be of little concern to non-scientists. Except that the whole edifice of global climate change policy is built on these scientific projections. The demand for an 80 per cent reduction in CO2 emissions, or the claim that if action is not taken in the next five years we will have passed the ‘tipping point’, are both based on what certain computer models tell us of future climatic trends. The strongest policy measures have emerged from the weakest part of the scientific argument.

The attempt of policy makers to play the trump card of science has had two consequences. On the one hand those who oppose the policy proposals often attack as false not just the future projections but the entire empirical edifice of climate science. On the other hand many climate scientists feel compelled to go beyond the tentative nature of their models in order to lend scientific authority to political policies they deem necessary. And this is what the hacked CRU emails really reveal – not a conspiracy to falsify data but the pressure to turn science into a form of advocacy.

‘I tried hard to balance the needs of the science and the IPCC, which were not always the same’, CRU scientist Keith Briffa writes in one email. The IPCC is the Intergovernmental Panel on Climate Change, the global scientific body charged with providing objective data on global warming. It is also charged with shaping policy. But as Briffa suggests, there is a gap between the scientific data and the IPCC’s political claims. The desire of scientists to act as advocates often makes them reluctant to engage with the arguments of those seen to be ‘on the other side’, refusing access to data even to respected academics such as the American economist Roger Pielke, threatening to destroy data rather than give it up and discussing how to stop papers regarded as pernicious from being published, including the possibilities of manipulating the peer review process.

Scientific research is, of course, not a pure, unsullied process. There are egos and agendas and the scientific equivalent of office politics. But the blank refusal to share information, the threat to destroy data and the manipulation of the peer review process discussed in these emails goes well beyond the normal cut and thrust of scientific debate.

The blurring of science and politics can be seen not just in the hacked emails but also in much of the response to their leaking. Many environmentalists and scientists have not just dismissed the leak as a storm in a teacup but have also insisted that the real issue is, in the words of the leading science journal Nature, ‘the harassment that denialists inflict on some climate-change researchers, often in the form of endless, time-consuming demands for information’. It’s a response that has left even George Monbiot, one of Britain’s leading green campaigners, aghast. ‘I have seldom felt so alone’, he lamented. ‘Confronted with crisis, most of the environmentalists I know have gone into denial’. It was, he observed a ‘profoundly ironic’ response ‘as we spend so much of our time confronting other people's denial.

The danger in all this is not just a corruption of science but also an emasculation of politics. The key debates about climate change are political, not scientific. How much resource should we put into mitigating emissions and how much into adapting to a warmer world? How do you deal with the fact that slower economic growth may produce less CO2 but may also make it harder for people in developing countries to climb out of poverty? How do we weigh the moral good of cheaper travel with the moral good of reduced emissions? And so on. These are debates about political principles and ethical values that no amount of scientific data can resolve. The trouble is, the more we insist that ‘the science tells us what to do’, the less we are able to engage in the kinds of debates necessary to resolve such issues. That is why the best outcome of the Copenhagen conference would not be a triumphant policy package agreed through a series of backroom deals and stamped with the authority of ‘science’ but an acknowledgement of the political and ethical dilemmas that climate change raises and a willingness to engage in open and democratic debate to resolve them.

Man-made global warming is not a hoax as many skeptics seem to believe, though neither is the science of climate change as settled as many environmentalists would have it. The real debate, however, only begins where the science ends.