The EPA was “unambiguously correct” in moving to set limits on industrial and automotive emissions of greenhouse gases including carbon dioxide, a federal appeals court said.

A federal appeals court on Tuesday, June 26, 2012 upheld the first-ever regulations aimed at reducing the gases blamed for global warming, handing down perhaps the most significant decision on the issue since a 2007 Supreme Court ruling that greenhouse gases could be controlled as air pollutants.

Read the court’s opinion here [PDF].

The rules, which had been challenged by industry groups and several states, will reduce emissions of six heat-trapping gases from large industrial facilities such as factories and power plants, as well as from automobile tailpipes.

A three-judge panel of the U.S. Court of Appeals in Washington said that the Environmental Protection Agency was "unambiguously correct" in using existing federal law to address global warming, denying two of the challenges to four separate regulations and dismissing the others.

EPA Administrator Lisa Jackson called the ruling a "strong validation" of the approach the agency has taken.

The court "found that EPA followed both the science and the law in taking common-sense, reasonable actions to address the very real threat of climate change by limiting greenhouse gas pollution from the largest sources," Jackson said in a statement.

Lawyers for the industry groups and states argued that the EPA should have considered the policy implications of regulating heat-trapping gases along with the science. They also questioned the agency's reliance on a body of scientific evidence that they said included significant uncertainties.

The judges - Chief Judge David Sentelle, who was appointed by Republican President Ronald Reagan, and David Tatel and Judith Rogers, both appointed by Democrat Bill Clinton - flatly rejected those arguments.

"This is how science works," the unsigned opinion said [PDF]. "EPA is not required to re-prove the existence of the atom every time it approaches a scientific question."

Industry groups vowed to fight on.

"Today's ruling is a setback for businesses facing damaging regulations from the EPA," said Jay Timmons, president and CEO of the National Association of Manufacturers. "We will be considering all of our legal options when it comes to halting these devastating regulations. The debate to address climate change should take place in the U.S. Congress and should foster economic growth and job creation, not impose additional burdens on businesses."

Environmentalists, meanwhile, called it a landmark decision for global warming policy, which has been repeatedly targeted by the Republican-controlled House.

"Today's ruling by the court confirms that EPA's common-sense solutions to address climate pollution are firmly anchored in science and law," said Fred Krupp, president of the Environmental Defense Fund.

The court also dismissed complaints against two other regulations dealing with pollution from new factories and other industrial facilities. The plaintiffs had argued that the EPA misused the Clean Air Act by only requiring controls on the largest sources, when the law explicitly states that much smaller sources should also be covered.

The judges, when presented with these arguments in February, cautioned the industry groups and states to be careful what they wished for. If EPA chose to follow the letter of the law, they said, greenhouse gas regulations would place even more of a burden on industry and other businesses.