WASHINGTON -– Four Republican former administrators of the Environmental Protection Agency had a message for the Senate on Wednesday on climate change: It's real, it's bad and the United States should do something about it.

But their fellow Republicans at the hearing largely ignored that position, instead repeating a variety of arguments about why the U.S. should not address the greenhouse gas emissions causing the planet to warm up.

The hearing before the Senate Environment and Public Works Subcommittee on Clean Air and Nuclear Safety focused on new EPA standards for reducing emissions from power plants. The standards, released on June 2, have been a major point of contention for congressional Republicans.

"We believe there is legitimate scientific debate over the pace and effects of climate change, but no legitimate debate over the facts of the earth's warming or over man's contribution," said William Ruckelshaus, who served as the EPA administrator under both Richard Nixon and Ronald Reagan.

Christine Todd Whitman, who served as the agency's administrator during the first years of George W. Bush's presidency, expressed frustration at critics who argue the EPA doesn't have authority to act on greenhouse gas emissions.

"The issue has been settled. EPA does have the authority," Whitman said. "The law says so, and the Supreme Court has said so twice. The matter should be put to rest. ... My hope is the primary focus will be on the substance of the proposed rule and not EPA's broad authority to promulgate it."

Lee Thomas, who served as administrator during Reagan's second term, and William Reilly, who served under George H.W. Bush, also testified at Wednesday's hearing. The four penned an op-ed together last year for the New York Times called "The Republican Case for Climate Action."

On the new power plant rule, the administrators expressed support for the action the EPA has taken under President Barack Obama.

"They've been as creative as I've ever seen them be," Whitman said in a meeting with reporters just before the hearing. "They've really made an effort. They’ve really gone out of their way to try to make it a workable rule."

"My sense is they've built in as much flexibility as possible," Thomas said in the meeting.

During the hearing, the subcommittee's Republicans raised a range of challenges to the EPA rules. Sen. David Vitter (R-La.) argued that the rules would have "serious economic consequences" while providing "no measurable impact on climate change." He also said he's "frustrated" by the "cartoonish" and "outlandish" claims that proponents of climate action make to dismiss critics of the science. Vitter has previously called evidence cited to support climate change "ridiculous pseudo-science garbage."

Sen. John Boozman (R-Ark.) criticized "expensive, big-government, left-wing climate policies." Jim Inhofe (R-Okla.) accused the EPA of trying to "force Americans to live out the president's green dream." Jeff Sessions (R-Ala.) challenged the idea that carbon dioxide is a pollutant.

"I would say CO2 is a different kettle of fish," said Sessions. "It's plant food. It's not a pollutant in any normal definition."

The Republicans called three witnesses for the hearing: a biologist who argues that climate change is not significantly affected by human activity; the attorney general of Alabama, who has fought other EPA actions in court; and an economist who criticized cap and trade (a policy previously debated in Congress to address climate change, but not, in fact, the policy that the EPA has put in place).

The senators and their witnesses thoroughly rehashed arguments that critics of climate action have made before. They said the Intergovernmental Panel on Climate Change, the UN body charged with synthesizing the current science on climate change, is wrong about global warming, and that scientists are cooking the books to exaggerate its importance. They also argued that even if climate change is happening, the U.S. cutting emissions won't mean anything unless China and India also cut emissions. Finally, they suggested cutting emissions will cost the U.S. economy billions of dollars and thousands of jobs.

Although they engaged with their witnesses, Republican subcommittee members mostly ignored the former EPA administrators. For visual effect, the hearing room was also filled with coal miners from Alpha Natural Resources and Murray Energy, who had been bussed into town overnight from West Virginia, Ohio and Pennsylvania for the hearing.

Before the hearing, the former administrators expressed optimism about getting more people in their party to back action on climate change.

"There are a lot of Republicans that believe that the climate is changing and that humans play a role in that," said Whitman. "They just need some cover."

That cover, she said, comes from public opinion turning increasingly toward the need to act.

"We feel strongly that something should be done, and we ought to get on with it," said Ruckelshaus.

Following the hearing, Reilly didn't seem too taken aback by the Republican response.