David Friedman has a different type of 'What if They're Right?' argument from mine here, which deals largely with political economy. His is more about the consequences of warming as more or less likely to be catastrophic. (Hell, I've always wondered why it wouldn't be beneficial to humanity and ecology, as in past non-anthropogenic warm periods.) Anyway, here's a good sliver:
But most of the argument is put in terms not of what might conceivably happen but of what we have good reason to expect to happen, and I think the outer bound of that is provided by the IPCC models. They suggest a temperature increase of about two degrees centigrade over the next hundred years, resulting in a sea level rise of about a foot and a half. What I find implausible is the claim that changes on that scale at that speed would be catastrophic—sufficiently so to justify very expensive measures now to prevent them.
Human beings, after all, currently live, work, grow food in a much wider range of climates than that. Glancing over a U.S. climate map, it looks as though all of the places I have lived are within an hour or two drive of other places with an average temperature at least two degrees centigrade higher. If people can currently live, work, grow crops over a temperature range of much more than two degrees, it is hard to imagine any reason why most of them couldn't continue to do so, about as easily, if average temperature shifted up by that amount—especially if they had a century to adjust to the change. That observation raises the question with which I titled this post: Does climate change catastrophe pass the giggle test? Is the claim that climate change of that scale would have catastrophic consequences one that any reasonable person could take seriously?
Find the whole post here. (HT: Michael Strong)
Remember that these 100 year, foot and a half sealevel rise predictions are the most extreme conditions made by a body who has strong incentives to bias their work in favor of warming. Indeed, empirical observations over the last ten years have seen no warming and no cooling. IPCC models predicted temperature increases, which simply haven't happened. Why should we trust their models on something even more difficult to predict -- i.e. future consequences of warming? I'd say ecologists like Dan Botkin are more qualified to talk about such consequences to the ecology. Indeed, I'm very sympathetic to Botkin's "non-steady state" view of the climate and ecosystem.