The regulatory approach has been studied and recommended by groups such as the Center for Biological Diversity, which has just joined 350.org in petitioning EPA to use the Clean Air Act for aggressive cuts in greenhouse gases. <a href="http://www.yesmagazine.org/planet/using-the-clean-air-act-to-cap-carbon">http://www.yesmagazine.org/planet/using-the-clean-air-act-to-cap-carbon</a> In an analysis issued earlier this year, the Center concluded: