I heard self-styled “Skeptical Environmentalist” Bjorn Lomborg talking about his new book, Cool It on NPR’s morning edition today. He accepts the findings of the Intergovernmental Panel on Climate Change (IPCC) that the Earth is warming due to human activities, but he argues for slower changes in policy than I think are needed.
I am pleased to see that his argument is over policy, and that he bases it on the recognized IPCC consensus. Where I think he went wrong was in neglecting some very significant error bars alluded to in the IPCC report.
Those who are raising the loudest warnings about consequences of anthropogenic global warming usually cite the risk of sea level rises of several meters, rather than the IPCC consensus of up to a half-meter by 2100. Indeed, if we could be sure that the consensus had small error bars, we could take the time Lomborg suggests to allow technology to catch up with the problem.
The reason I argue for a stronger technological and policy push is that the IPCC report includes a caveat that the sea level prediction assumes that there will not by dynamic melting of the Greenland and West Antarctic Ice Sheets. There are recent signs that such melting may be taking place.
Calculating a sea level rise based on those preliminary measurements would require a nonlinear extrapolation based on fragmentary data. That’s not the kind of thing that belongs in an international consensus. Yet it is plausible enough to be factored into policy-making decisions.
By the time the next IPCC report comes out, we’ll know more about those early signs. If we are indeed on the threshold of dramatic changes in melting, more dramatic–and more costly–policies will be in order.
In the NPR interview, Lomborg ignores that caveat and the signs that dynamic melting may be happening. By doing so, he can make a good economic case for delay. That approach makes it possible for him to mis-characterize the stance of those who think the caveat deserves attention as alarmist.
I call it prudent urgency instead. I think the admonition to “Cool It,” at least as stated in the interview, is misguided.
I haven’t read the book for review on my Science Shelf book review archive, but I would welcome thoughtful reviews, whether favorable or unfavorable, from readers. See my guidelines for contributors page for details on how to submit a review.
