From the Washington Post:
The Obama administration formally declared Monday that carbon dioxide and other greenhouse gas emissions pose a danger to the public's health and welfare, a move that lays the groundwork for an economy-wide carbon cap even if Congress fails to enact climate legislation. The move, announced by Environmental Protection Agency administrator Lisa P. Jackson, comes as the largest climate change conference in history gets underway in Copenhagen. It finalizes an initial "endangerment finding" by the government in April.
Read the rest here.