Tyler Cowen at Marginal Revolution and the Economist magazine explain why buying “carbon offsets,” like paying someone to plant trees to make up for your airplane flights or electricity usage, aren’t as wonderful an idea as they may sound. (von at Obsidian Wings refutes wingnut attempts to exaggerate the point.)

There’s a lot of wonkery involved, but here’s the gist:

“Many readers profess puzzlement as to how carbon offsets could fail to reduce one’s carbon footprint.  The answer is that they probably do reduce one’s carbon footprint, but by nowhere near the one-for-one ratio that seems to be implied by the extraordinarily low price of carbon offsets.  Unless they are implemented under a cap-and-trade system [where there are legal limits on the total amount of carbon emitted], these sorts of environmental efforts are plagued by something called the rebound effect, which is to say that using more efficient technologies causes the price to fall, which causes people to use more of the carbon-emitting substances in question.” (Economist)

It gets worse:

“Furthermore if you simply buy less of a non-storable good such as electricity, price to other demanders will go back down and social quantity consumed will not change.” (Cowen)

There really is no substitute for some kind of collective action to start reducing carbon consumption. That can take either command-and-control forms like regulating and subsidizing, or market-based forms like cap-and-trade systems or a carbon tax. That discussion is about to heat up on both federal and state levels, as David Greising reports in Friday’s Tribune.