Contrary to the "natural capitalism" arguments that are all the rage nowadays, it looks likes the real world applications of "green" thinking haven't been quite as successful or smooth. It's like the problem with hybrid cars. Either you pay the premium to buy the Prius that "looks" green and everyone knows it (i.e. you're buying a fashion statement) or you ignore the hybrids. So too with most businesses buying RECs (renewable energy credits) that make them look good but have no real impact in reducing carbon emissions or a few businesses are paying the premium to do some "real" carbon-reducing projects at a significant financial cost. The in between "hybrid" strategy isn't happening, and that's where the real gains are to be made.
http://www.businessweek.com/magazine/content/07_44/b4056001.htm
At least in the U.S. . . . Going further afield, we see that man-made coal fires in Chinese mines alone are causing 2-3% of the entire world's CO2 emissions, the equivalent of all of the cars in the U.S. Spend some money to bring a few of those under control, and you'll do more to deal with real CO2 emissions than all of our current efforts in the U.S.!
http://www.gi.alaska.edu/~prakash/coalfires/co2_emission.html
http://unpan1.un.org/intradoc/groups/public/documents/APCITY/UNPAN025914.pdf