The question of climate change has finally moved on from is it happening? to what should we do about it?.

There has been some great discussion here at Grist on carbon trading vs. carbon taxes (e.g., here or here).

For those who want more, Bill Chameides, chief scientist of Environmental Defense, was on Science Friday to talk about carbon trading. Check out the mp3 here.

Bill basically reiterates the points he made here on Gristmill a while back. But it’s still worth listening to.