Clouds and Climate

Catching up on my reading last night (I get too many weekly science magazines*, all of them good), I curled up last night with a piece in the July 24 New Scientist (apparently not on line) by Fred Pearce about uncertainties in the climate models because of water vapor and clouds.

Pearce talks about relatively new model results suggesting that uncertainties over water vapor feedbacks are creating a big tail on the warm side of the curve of uncertainty over CO2 doubling - in other words, increasing the odds for Earth ending up on the warm side of the one to twelve degree C warming range.

The story gives a good accounting of what the uncertainties are, and why water vapor is hard for the modellers. But then Pearce concludes with these frankly astonishing comments:

Some climate scientists find these new figures disturbing not just for what they suggest about the atmosphere's sensitivity to greenhouse gases, but also because they undermine existing predictions. Uncertainty about those predictions is stopping politicians from acting to halt global warming. So, they argue, even suggesting that the model results are less certain could be politically dangerous.

But other climate scientists fear creating a spurious certainty about climate change. Since we don't know what the future holds, they say, we shouldn't claim to know. These people see the predictions of climate models as less like a weather forecast and more like a bookmaker setting odds for a high-stakes horse race. There are no "dead certainties". They say that humanity has to act prudently and hedge its bets about future climate change in the absence of certainty. We will, they argue, never be able to see through the clouds, and politicians will just have to accept that.

I rather wish Pearce had named names here, especially the scientists described in the first paragraph above who seem to think that they ought not be sharing the truth with the public and policy makers lest we get all confused about what to do about greenhouse climate change. That "we're scientists and we know best" attitude is the sort of profound arrogance that has gotten scientists into trouble on the climate change debate.

* I'm getting New Scientist, Science, Nature and Science News right now - all terrific, but who has time to read it all?

Posted by John Fleck at September 15, 2004 07:59 PM