Plants turn out to be a source of a greenhouse gas.

A new study in Nature suggests that living plants are actually producing methane, a major greenhouse gas. If you have a Nature subscription, you can read the study here. Here is the response at Realclimate.org. Here is an article from the Financial Times about it. Here is the Guardian article.

If the results hold up, and this methane turns out to persist in significant levels in the atmosphere, they will affect climate science and global warming negotiations. Climate models will have to be rejiggered. The credit nations get for forest cover in the Kyoto protocol should be reduced. Details of the fallout have not been determined yet. There is some nice romance to the discovery itself. The researchers "acted on a hunch after they found hints of methane from leaves left in an incubator" and everyone else is now slapping their foreheads saying "how could we have missed this?"

The Financial Times article uses this as an opportunity to undermine confidence in climate models in general. Although the author says global warming is real, and that these results only affect how we should respond to this, the subtext seems to be, “Hey look, scientists keep changing their minds, so why should we ever make plans based on scientific predictions?”

This kind of reasoning is what I call the “Sleeper fallacy”, after the Woody Allen movie where Allen plays an owner of a health food store who wakes up in the future to find that smoking and fatty foods are now good for you. It’s funny, because we can imagine that changes in science could make almost anything good for you. But that doesn’t really change anything. You can’t justify taking up smoking now just because at some point in the future it might be found to be healthy. You act on the best information currently available to you. The difficulty in determining the consequences of your actions does not absolve you of the responsibility to act with as much foresight as you can.

(via Steve H via email.)