Saturday, March 17, 2007

Climate scientists in epistemological lather

I awoke today to the depressing sound of an eminent climate scientist arguing that other eminent climate scientists were going too far in making alarming statements about climate change. The self-styled purist was gathering at a Sense about Science meeting and was heroically guarding the pristine truths of science from the barbarians of the American Association for the Advancement of Science and their climate change statement. He said he was doing this in order to preserve the trust of the public in the pronouncements of scientists - fat chance. Well he's made a mess of that..! All blown wildly out of proportion in a BBC story and interview in which, Prof Paul Hardacre, the scientist with the gripe, completely failed to explain what he was concerned about. All involved professed support for the findings of the IPCC and Prof Hardacre even said he "agrees with everything in the [AAAS] statement", but didn't like the way it was phrased.

We sometimes get cri de couer from scientists - worried that their discipline is misunderstood. The basic problem is a difference in scientific method for the exploration of knowledge, and scientific assessment to give advice for policy making. In the former, one has the right (and some say the obligation) to reserve judgement indefinitely as there is no imperative to come to a conclusion, but every reason to go on attempting to falsify the lead hypothesis in order to strengthen and widen its applicability. In the latter, one has to assess the state of knowledge and be insightful about uncertainty - using careful wording to convey probability and what is known and not known. For example, the AAAS statement says:

As expected, intensification of droughts, heat waves, floods, wildfires, and severe storms is occurring, with a mounting toll on vulnerable ecosystems and societies. These events are early warning signs of even more devastating damage to come, some of which will be irreversible.
This does reflect real observations, and these observations are consistent with the theory of climate change and are predicted by models built on the theory. But the state of knowledge is not yet such that these events can always be unequivocally attributed to climate change as the cause. There may be many reasons why these causal relationships aren't established with near complete certainty: the historical record may flaky; more measurements for longer may be needed; confounding theories may not have been adequately tested; and, er, they might be wrong. Scientific method says reserve judgement until causation is established, but scientific assessment for policymaking says that observations consistent with the dominant theory are important confidence-building facts to communicate to the public and policymakers.

I put this fake and ill-conceived row in the category of 'Climate Porn' to borrow IPPR's term - and I think it adds another category to their ten: the Irritated Boffin, annoyed by too much 'unscientific' media coverage, devoid of the pages of caveats and hedging that fills scientific papers. Also see IPPR's Warm Words report on how we are communicating climate change.

I think the problem is more the other way. As I argued in my piece about What the IPCC does and doesn't tell us, the attempt to put a very strict scientific filter on an assessment for policy-makers has the effect of understating the dangers. A pure scientist loses nothing from not saying something, but in my view it is 'reckless caution' for a scientist providing advice to underplay or ignore particular observations just because there is not full certainty about them.

No comments: