text:  Let's go back to the calls. Charles in Sebastopol, California. Welcome to the program. Charles, you are on the air with us. Thanks so much, and thanks for having me. Great topic. A couple of things I can squeeze in. Two things. First of all, I've really been taking a close look at carbon credits as a trading mechanism, as a fiduciary instrument. This has been going on for years. I think this is really part of the larger picture of the economics of...