In case you hadn't noticed, discussion of global warming has become somewhat polarized. Amid accusations, on the one hand, that industry-financed non-experts deliberately sow confusion, and on the other that a leftist cabal exaggerates the risks and threatens our economy, Roger A. Pielke, Jr. is something of an anomaly.
A professor of environmental studies at the University of Colorado, Pielke is an expert who endorses the broad consensus that humans are causing dangerous changes. But he also criticizes scientists like those on the Intergovernmental Panel on Climate Change for stifling legitimate dissent in the service of narrow policy options. In his 2007 book, The Honest Broker: Making sense of science in policy and politics, Pielke touches on climate change only tangentially as he outlines how scientists can more constructively contribute to contentious policy decisions.
Reading the title, I thought at first that I understood what Pielke meant by an "Honest Broker." As an undergraduate thirty years ago I dabbled in the still-young academic field of Science, Technology, and Society. Books like Advice and Dissent: Scientists in the political arena, by Joel Primack and Frank Von Hippel illustrated how scientists who step outside their specialized knowledge to advocate particular policies risk both their own credibility and that of science. To preserve the authority of expertise, scientists should be careful and clear when they spoke outside of their specialty.
But the intervening years, Pielke says, have shown that the whole notion that science provides objective information that is then handed over to inform policy makers, the so-called linear model, is naïve and unrealistic. Only rarely, when people share goals and the relation between causes and effects is simple, can scientists meaningfully contribute by sticking to their fields of expertise as a "Pure Scientist" or by providing focused answers to policy questions as a "Science Arbiter."
More frequently, people do not share goals and the causal relationships are more complicated. Scientists who wish to contribute to these policy debates are naturally pulled into the role of "Issue Advocate," marshalling the science in support of a narrowed range of politically-supported options. Although this is a useful role, Pielke warns, scientists often drift into it unwittingly. As they deny any political influence on their scientific judgments, these "stealth issue advocates" can damage the authority of science even as they obscure the true nature of the political decision.
To address this problem, Pielke pleads for more scientists to act as "Honest Brokers of Policy Alternatives," to give his complete description. Such scientists, presumably as part of multi-disciplinary committees like the now-defunct Congressional Office of Technology Assessment, would act to expand the available policy alternatives rather than restrict them. Unlike the science arbiter, Pielke's honest broker recognizes an inseparability of policy issues from the corresponding scientific issues, but nonetheless provides a palette of options that are grounded in evidence.
In my technology research, I've had my own complaints about the analogous linear model. I've found that pure research often leads to more research, rather than to the promised applied research and products that make everyone's lives better. But Pielke's criticism of the linear model is more fundamental. He correctly notes that in many complex situations, scientific knowledge does not, on its own, determine a policy outcome. But he then seems to conclude that there is no legitimate role for objectively valid science that can narrow policy options.
In discussing Bjørn Lomborg's The Skeptical Environmentalist, for example, Pielke says "Followers of the linear model would likely argue that it really does matter for policy whether or not the information presented in TSE is 'junk' or 'sound' science." He then shows that for some criticisms of the book, the validity of the science was irrelevant to policy. But many of the standard talking points raised by global-warming skeptics are well within the bounds of science, so clarifying them is a useful narrowing of options, even if it doesn't lead to a single, unanimously correct policy.
Nonetheless, Pielke's short, readable book provides a helpful guide for what we can hope for in policy debates involving science, and how scientists can most productively contribute. What we can't hope for is a single, science-endorsed answer to complex issues that trade off competing interests and conflicting values. For that, we have politics.