Reality Bites Back

"The problem with offsets is that they always involve comparing a real situation with a counterfactual situation." That's the Caregie Institute's Ken Caldeira, as quoted in this excellent article in Conservation Magazine ("That Sinking Feeling," by Nick Atkinson) about the practice of planting trees, or, better yet, avoiding deforestation, in order to slow global warming. The concept is simple: trees sop up C02, so by planting more of them, we can (theoretically) offset the emissions from that flight to New York or road trip to Vegas. Alas, it's not so simple.