The endangerment finding also provides a legal foundation for the clean cars program, an agreement announced by Obama and leaders in the auto industry earlier this year to limit greenhouse gas emissions from vehicles.

Endangerment Finding Answers a 3-Year-Old Supreme Court Ruling

The finalizing of the endangerment finding finally puts the U.S. government in line with a nearly 3-year-old Supreme Court ruling that had been ignored by the previous administration.

In Massachusetts v. EPA, the high court found in early 2007 that EPA has the authority to regulate greenhouse gases and under the Clean Air Act and ordered the EPA to make a determination based on science: If the agency found greenhouse gases posed a danger to public health and welfare, the EPA would have to begin setting standards to regulate greenhouse gases emissions from motor vehicles.

The Bush administration’s EPA did draft an endangerment finding later that year stating that “air pollution of elevated levels of greenhouse gas (GHG) concentrations may reasonably be anticipated to endanger public welfare.” However, the Bush-Cheney White House never opened the draft.

“Now that the U.S. government has officially ended its era of climate denial, the real endangerment to our planet comes from those who continue to deny the science and delay taking any action,” said Rep. Ed Markey (D-Mass.), a co-sponsor of the ACES bill.

Sierra Club Executive Director Carl Pope praised the Obama administration for following through on its campaign pledge to act to slow climate change.

"By shifting to clean energy and cracking down on the corporations that pollute the water we drink and the air we breathe, we can restore our economy to prosperity and reduce our dependence on oil and coal, all while tackling global warming," Pope said.

"This is one more key commitment President Obama can bring to the world to show that the U.S. will do its part to fight global warming.”

See also:

How Tom Delay Sparked the EPA’s Greenhouse Gas Endangerment Finding

EPA Releases Bush Administration's Proposed Greenhouse Gas Endangerment Finding

Senate Bill Puts EPA Back in the Climate Game, and the Agency Wastes No Time