Paul Krugman: Cassandras of Climate

Every once in a while I feel despair over the fate of the planet. If you’ve been following climate science, you know what I mean: the sense that we’re hurtling toward catastrophe but nobody wants to hear about it or do anything to avert it.

And here’s the thing: I’m not engaging in hyperbole. These days, dire warnings aren’t the delusional raving of cranks. They’re what come out of the most widely respected climate models, devised by the leading researchers. The prognosis for the planet has gotten much, much worse in just the last few years.

What’s driving this new pessimism? Partly it’s the fact that some predicted changes, like a decline in Arctic Sea ice, are happening much faster than expected. Partly it’s growing evidence that feedback loops amplifying the effects of man-made greenhouse gas emissions are stronger than previously realized. For example, it has long been understood that global warming will cause the tundra to thaw, releasing carbon dioxide, which will cause even more warming, but new research shows far more carbon locked in the permafrost than previously thought, which means a much bigger feedback effect.