Freakonomics: The Consequences of Being Green
I'm going to say it again. I really like economics. Especially FREAKONOMICS!
This article is short and simple, like most of blogger Daniel Hamermesh's entries, but I like it more than a few of his others. Most just explain basic economic principles and apply them to real world events. But this leaves a little more room for interpretation, and I enjoyed all the comments as well.
But this is the best, "There should be a rule: before helping the environment in one market, we should be required to think through the impacts on other markets."