Books: certainty and subjectivity

Getting to grips with “Science as a Contact Sport”, Oliver Morton found that Stephen Schneider has zeroed in on some issues and events in ways no one else could or would.

Science as a Contact Sport: Inside the Battle to Save Earth’s Climate
Stephen H Schneider
National Geographic, 2009

To sit next to Steve Schneider while listening to someone else give a talk about climate science is like watching a DVD with a commentary track by an insightful but rather grumpy director. As the speaker makes her points, Schneider, a veteran climate scientist now at Stanford University, will mutter about who first made all the interesting points in the talk, and when this or that bit of science was first appreciated, and how stupid people have been not to act on this knowledge years ago.

The purpose is to remind anyone listening than climate science has a history, if a fairly brief one, and that the message of that history is reasonably consistent — scientists have believed much what they believe now about global warming for decades, and if climate scientists in general and Schneider in particular had been listened to better, the world would have faced up to the issue better and sooner.

This personal memoir by Schneider provides a similar effect. It is not the best introduction to the development of climate science in recent decades — that is Spencer Weart’s The Discovery of Global Warming — but it is personal and heartfelt, and zeroes in on some issues and events in ways no one else could or would. There is much here on the recent history of the Intergovernmental Panel on Climate Change (not so recent as to include the current charges of error and calls for reform), on the negotiation at Kyoto, on taking on the corporate carbon lobby over the past 20 years. But perhaps the most intriguing material comes earlier than that, as the origins of debates familiar today are revealed in the decades gone by.

The account of the 1970s, and of Schneider’s coming into his scientific own amid the first stirrings of scientific and political concern about what could be happening to the climate, is fascinating. It shows, from the inside, quite how little was known at the time and how much room for progress there was. In so doing, it also, incidentally, makes clear that one of the trivial claims commonly made by those who doubt the importance of global warming — that there was a widespread consensus on global cooling a few decades ago — is bunk. And it shows how hard it was to start building bridges between the natural and social scientists who had something to offer — a process still not fully achieved, and into which Schneider has put much effort.

There is a fascinating early encounter, one that prefigures many future debates, between Schneider and Richard Lindzen. In 1972 they were both on a panel convened in Fort Lauderdale, Florida, to begin an evaluation of the risks posed to the stratosphere by aviation. Lindzen, who is now well known as one of the few academic climate scientists to disagree with his colleagues’ consensus on the likely effects of increased carbon dioxide, argues that, over the next couple of years, there is no way that the science involved will permit certainty, and that scientists should resist all political pressure to provide answers under such conditions.

Mike MacCracken — like Schneider now one of the respected elders of climate science — responds that they should not claim a certainty they don’t have, but that they should outline the range of possibilities and the research that might narrow that range. Lindzen is unconvinced — he thinks science too noble for such a subjugated role. Schneider wades in with a partisan point — that scientists’ guesses will be better than those of US Republican politicians. Lindzen gets even crosser, and leaves shortly afterwards.

That anecdote will confirm what some already think of Schneider — that he is happy with political guesses that serve his purpose. In fact it says something different: that he knows that scientists need to communicate, precisely, what is certain and what is not, and that when working on policy they need to go further than they would in academia by giving subjective estimates of how likely or not they are to be wrong. This is not the only model for processes by which scientists can advise politicians, but it is undeniably a powerful one. In trying to put this approach on to a firm and transparent footing within the IPCC — to make it clear what is subjective, and to provide consistent language that expresses how strong the consensus around such conclusions is — Schneider did that organisation a great deal of good.

Those who, reading this, think Schneider always bring his politics into things may be surprised by the subsequent chapter on the 1980s debate on nuclear winter, a subject that those thinking about climate policy and science would do well to study more than they do. It was with nuclear winter — and specifically the claim by Carl Sagan and colleagues that even a relatively small nuclear war would lead to a global climatic spasm perhaps serious enough to bring about human extinction — that computer models of the climate first became politicised in America, with the right, broadly construed, eager to pick holes in Sagan’s work (a project not without possibilities of success).

Schneider was a friend of Sagan’s, and probably also saw him to some extent as a role model — suave, engage, swooningly good at communicating. Sagan had introduced Schneider to the delights of appearing on US television’s then-popular Tonight Show with Johnny Carson, though Schneider blew it by upstaging his host. Schneider had actively encouraged Sagan to take on a greater role in public policy and on political issues. What’s more, Schneider was, like most American liberals, opposed to the Reagan administration’s arms build-up. But Schneider’s modelling disagreed with Sagan’s, and Schneider thought Sagan was underplaying uncertainties. He said so in public, and was taken up by Sagan’s critics. Their friendship, unsurprisingly, suffered. But Schneider was guided by what he thought was right and responsible.

In a few weeks, I will have the good fortune to be at a meeting in California where I will be able to sit next to Schneider and hear him giving a running commentary on what’s smart, what’s dumb and how long A, B and C have been known. You will probably not — but this book will give you a taste of what that experience is like, and what can be learned from it.

Oliver Morton, a British science writer and editor, is the author of Eating the Sun.