GHG's now fall under the Clean Air Act...

The United States' Environmental Protection Agency (EPA) has formally recognized a number of greenhouse gases, including carbon dioxide (which contribute to climate change) as "endanger[ing] public health and welfare". This has huge implications for climate change policy in the United States, as these gases will now fall under the jurisdiction of the Clean Air Act which prohibits the discharge of some of the world's most dangerous polluting chemicals into the air.

This is being recognized as the first step in the United States towards a significant climate change policy. Unlike his predecessor, Barack Obama is pursuing relatively ambitious climate change policies, even in the face of a tremendous economic downturn.

Interestingly, this move by the EPA may not sit well with Obama. With the new rules, the EPA would be able to regulate emissions of the GHGs. Obama, on the other hand, does not seem as interested in regulation as he does in implementing a cap-and-trade system, which would instead rely on economics rather than governmental laws. Depending on the level of regulation from the EPA, a cap-and-trade system is generally considered to be less harmful to business than regulation.

In any case, it is a very important step in a long process to establishing an effective climate change policy.