Climate change and the National Academy of Sciences

Early last week the U.S. National Academy of Sciences held a summit on America's Climate Choices. It was part of the Academy's response to a request from Congress that it provide advice on how the U.S. should respond to climate change. The suite of studies the Academy will produce draws on experts from government, business, nongovernmental organizations, and research and educational institutions (more details at the project web site).

As the editors of Nature point out:

On the face of it, this sounds as though Congress was asking the NAS for specific policy choices -- a request that could lead the academy into dangerous territory. Although it has recommended specific policies in the past, the academy runs the risk of politicizing itself and weakening its standing should it advocate policies such as the stabilization of carbon dioxide at a particular atmospheric concentration, or the adoption of a US cap-and-trade programme. These are not scientific decisions: they depend on how much society is willing to spend on curbing CO₂ emissions versus how much it is willing to live with the results -- a fundamentally political problem. (emphasis mine)

I've made points like that a couple of times before.¹ It's important that scientists distinguish between questions science can answer -- what are the consequences of particular policy choices? -- from those it can't -- which consequences are desirable and how much are they worth? Science should inform policy choices, but it cannot determine them.²