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The Worst of All Worlds

COPENHAGEN – Have you noticed how environmental campaigners almost inevitably say that not only is global warming happening and bad, but also that what we are seeing is even worse than expected?

This is odd, because any reasonable understanding of how science proceeds would expect that, as we refine our knowledge, we find that things are sometimes worse and sometimes better than we expected, and that the most likely distribution would be about 50-50. Environmental campaigners, however, almost invariably see it as 100-0.

If we are regularly being surprised in just one direction, if our models get blindsided by an ever-worsening reality, that does not bode well for our scientific approach. Indeed, one can argue that if the models constantly get something wrong, it is probably because the models are wrong. And if we cannot trust our models, we cannot know what policy action to take if we want to make a difference.

Yet, if new facts constantly show us that the consequences of climate change are getting worse and worse, high-minded arguments about the scientific method might not carry much weight. Certainly, this seems to be the prevailing bet in the spin on global warming. It is, again, worse than we thought, and, despite our failing models, we will gamble on knowing just what to do: cut CO2 emissions dramatically.