The EPA today ruled that greenhouse gases are pollutants, and thus can be regulated by the EPA. This is potentially a game-changing decision, since it says that greenhouse gases cause substantive harm to people, just like sulfur emissions (acid rain), CFCs (ozone hole), or mercury (drinking water, fish), which are all regulated. No rules or even targets have been announced, and the EPA (and Obama administration) say they would rather have Congress control greenhouse gas emissions. The bottom line, though, is that if Congress drops the ball (yet again) on adopting strict regulations on greenhouse gas emissions, the administration now has a strong case in stepping forward with its own set of rules. See story in NYTimes.com for more details.