Newsweek: Economist Peter Nickerson, 56, is a proud resident of Seattle, arguably the capital of green America, so it almost goes without saying that he supports aggressive environmental policies. He’d like to see his city make public transit free to reduce vehicle emissions. He wants to ban pesticides in rivers where salmon swim. He’s a devoted recycler who even composts his own trash. Surely, then, he must love Seattle’s new bag tax? (Starting in 2009, it would require drug, grocery and convenience …