What the “Skeptics” of Climate Catastrophe are Skeptical Of: Nordhaus Reconsidered

The most frustrating thing about being a scientist skeptical of catastrophic global warming is that the other side is continually distorting what I am skeptical of.

In his immodestly titled New York Review of Books article “Why the Global Warming Skeptics Are Wrong,” economist William Nordhaus presents six questions that the legitimacy of global warming skepticism allegedly rests on.

1. Is the planet in fact warming?
2. Are human influences an important contributor to warming?
3. Is carbon dioxide a pollutant?
4. Are we seeing a regime of fear for skeptical climate scientists?
5. Are the views of mainstream climate scientists driven primarily by the desire for financial gain?
6. Is it true that more carbon dioxide and additional warming will be beneficial?

Since the answers to these questions are allegedly yes, yes, yes and no, no, no, it’s case closed, says Nordhaus.…

Opposite Views on Climate Feedbacks (and perhaps the answer lies in the middle)

Just how much warming should we expect from rising levels of atmospheric greenhouse gases (GHGs)? The answer largely hinges on how much extra warming might be generated by the initial warming—that is, how strong (and in what direction) are the feedbacks from water vapor and clouds.

By most estimates (including climate model outcomes), these feedbacks are positive and result in about a doubling of the warming that would result from greenhouse gas increases alone. By others, however, the total feedbacks are negative,…