Can carbon offsets backfire?

Al Gore and I both try to offset our carbon emissions. Are we actually making things worse when we think we’re making things better? The Economist and Tyler Cowen both try to make the case, and both are quickly slapped down by commenters including Joshua Gans. I’m not going to try to work out who has the better economics here, but I do think that organizations such as Climate Care, which sell such offsets, would do well to examine in some detail any possible unintended consequences associated with the areas they spend their money.