A continuation of our discussion of scientific input into policy debates:
The climate change debate is unusual in that scientists are understood as being almost monolithically on one side of the debate; in the public eye it is common to view it as The Scientists vs. The Politicians. Part of this is because of the cognitive biases of scientists and the blurring between positive and normative positions, and these are effects we see in other debates, for instance about public health in third world countries. But part of this phenomenon is structural: even under ideal cases, the debate about costs and benefits are split across disciplines. One technocratic approach to evaluating climate change would be as follows:
1. Climate scientists estimate the extent of anthropogenic climate change, creating a graph of emitted greenhouse gases vs oC change in temperature, with nice error bars.
2. Economists calculate the costs of any arbitrary temperature change, along with the costs of an adjustment to any arbitrary CO2 emission level. They find the point at which marginal cost equals marginal benefit.
3. Political scientists refine this estimate by calculating the probable public-choice inefficiencies of government policies. They formulate the optimal policy, which will probably reduce emissions slightly less than the economists’ model proposes.
Even in this model, when everyone stays inside their disciplinary lines, scientists will be in the position of pointing out the costs of our current choices. It is up to the social scientists to say yes, this is true, but the adjustment to lower emissions levels is not costless.
Given these roles, and given that scientists, politicians, and journalists all have their own axes to grind, it is not surprising that scientists are often presented as being monolithically on the interventionist side on the climate change debate. The only way for their research not to be simplified into “Needs Action Now!” is if it claimed that either climate is static or that climate cannot be changed by man, both of which are almost certainly false. But the sophisticated observer would note that their contribution is but one link on a long logical chain, a chain that needs to be viewed in its entirety to support an argument pro or con. And honest (and modest!) scientists and journalists would do well to keep that framework in mind.