Steve Rayner has an editorial in the Feb 2006 issue of Global Environmental Change – What drives environmental policy? about science and public policy. He writes:

Rather than resolving political debate, science often becomes ammunition in partisan squabbling, mobilized selectively by contending sides to bolster their positions. Because science is highly valued as a source of reliable information, disputants look to science to help legitimate their interests. In such cases, the scientific experts on each side of the controversy effectively cancel each other out, and the more powerful political or economic interests prevail, just as they would have without the science. This scenario has played out in almost every environmental controversy of the past 25 years (Sarewitz 2000).

This phenomenon has led to a widespread pathology: the use of bad arguments for good causes.

In the wake of Hurricane Katrina, the media on both sides of the Atlantic wasted no time in attributing it to global climate change. Leading members of Britain’s scientific establishment, including the Chairman of the Royal Commission on Environmental Pollution and the President of the Royal Society were quoted in the national media as implying that the damage caused by the 2005 hurricane season could be laid at the door of greenhouse gas emissions. For example, Lord May was quoted in The Guardian as saying:

“Nobody can say that global warming played no part in the unusual ferocity of hurricanes Katrina, Rita and Wilma. The estimated damage caused by hurricane Katrina alone was equivalent to 1.7% of US GDP. This is an insight into the economic cost to the developed world.”

Apart from the fact that Lord May would be the first to point out that science cannot prove a negative, both the science and the economics behind the attribution of high storm damage losses to greenhouse gas emissions remain decidedly dodgy. Pielke et al., (2005) remind us of three reasons.

First, although some work (e.g., Emanuel, 2005) is suggestive, and the idea is quite plausible, no connection has yet been established between greenhouse gas emissions and the behaviour of hurricanes (Intergovernmental Panel on Climate Change, 2001; Walsh, 2004). Second, the peer-reviewed literature strongly suggests that any future changes in hurricane intensities will be small in relation to observed variability (Henderson-Sellers et al., 1998; Knutson and Tueya, 2004). And third, the future damage costs of projected changes in hurricane behaviour are likely to be dwarfed by growing wealth and population (Pielke et al., 2005). But, most importantly, a series of studies by Pielke indicates clearly that the overwhelming factor explaining the seemingly inexorable trend towards increased costs of hurricane wind and water damage is not increased storm intensity. Much more important, by orders of magnitude, is the increasing propensity to build expensive infrastructure in coastal margins and flood plains and to destroy the buffering capacity of natural terrain. While there are many good reasons to argue for greenhouse gas emissions reductions, the evidence suggests that reducing storm damage costs is simply not among them.

The danger of using bad arguments for good causes, such as preventing unwanted climate change, is two-fold. Generally, it provides a dangerous opening for opponents who would derail environmental policy by exposing weaknesses in the underlying science. Specifically, it leads to advocating policies for reducing future storm impacts that are likely to be ineffective in achieving their declared aim. With or without greenhouse gas emissions reductions, the costs of storm damage are bound to rise. Reducing greenhouse gas emissions will have far less impact on storm damage costs than moving expensive infrastructure away from coastal margins and flood plains.

For good or ill, we live in an era when science is culturally privileged as the ultimate source of authority in relation to decision making. The notion that science can compel public policy leads to an emphasis on the differences of viewpoint and interpretation within the scientific community. From one point of view, public exposure to scientific disagreement is a good thing. We know that science is not capable of delivering the kind of final authority that is often ascribed to it. Opening up to the public the conditional, and even disputatious nature of scientific inquiry, in principle, may be a way of counteracting society’s currently excessive reliance on technical assessment and the displacement of explicit values-based arguments from public life (Rayner, 2003). However, when this occurs without the benefit of a clear understanding of the importance of the substantial areas where scientists do agree, the effect can undermine public confidence.

Link via the Science Policy weblog Prometheus, where Roger Pielke Jr comments on Steve Rayner’s editorial.