In a major announcement in Washington, the Environmental Protection Agency finalized their “endangerment finding” on carbon dioxide and other greenhouse gases. Under the Clean Air Act, the EPA could use this finding to announce major limits on major emitters.

Lisa Jackson spoke to reporters today, saying that there is an overwhelming amount of scientific studies and evidence showing that greenhouse gas emissions are “deteriorating the natural balance in our atmosphere and hurting our climate.” The decision made today shows that “this Administration will not ignore science or the law any longer,” and shows that “the United States government is in the arena on clean energy and climate solutions.”

The endangerment finding was compelled by a 2007 Supreme Court ruling, which judged that the Clean Air Act is written to include greenhouse gas pollution. This authorizes the EPA to make “reasonable efforts,” as Jackson put it, to reduce greenhouse gas emissions under the Clean Air Act.

Under the finding, which can be found here, large emitters at “stationary sources” that burn over 25,000 tons of CO2 per year would have to monitor their GHG emissions starting next month. By 2011, that data would need to be publicly available to allow emissions tracking. Starting next spring, this stationary source emitters would need to use the “best available technology” to reduce or control their emissions should they expand or retool their factories. The EPA would have to put out technical guidance on that technology, and then work with states to implement the measure.

This would also finalize the clean cars rule which was announced back in September, providing the endangerment finding that allows the EPA to regulate.

Jackson was quick to bat down concerns about the hacked emails in “Climategate,” saying that in their finding they relied on “decades of sound, peer-reviewed scientific data.” She said that there is nothing in the stolen emails that calls into question the voluminous science on which their decision was based.

Many have speculated that the EPA is moving forward to encourage Congress to act and get a bill to the President’s desk. Under this theory, the finding is the hammer, suggesting that the government will choose to move forward with or without Congress’ input. Jackson said that she continues to believe legislation is the best way to move forward on clean energy and mitigating climate change, for a variety of reasons. She said that “this is not an either/or proposition, but both/and.” She thinks the Clean Air Act regulations can supplement a solution in Congress. And as a threat to public health and welfare, the EPA has no choice but to act on GHG emissions, as per the Supreme Court ruling. “My intention here is to follow up on a three year-old requirement from the Supreme Court that we address greenhouse gas pollution,” Jackson said. She said that Congress would have the benefit of a reporting inventory on emissions when they finally construct their legislation.

Carl Pope of the Sierra Club praised the finding. “As the major global warming summit begins this week in Copenhagen, this announcement couldn’t come at a more important time. The Obama administration has followed through on its pledge to act and is demonstrating that the U.S. has turned away from eight years of inaction under the Bush administration.”

Obviously, the timing of the talks in Copenhagen show “a clear demonstration of commitment” in this area, as Jackson said.

The Financial Times has more.