Under the agreement, the U.S. would reduce carbon emissions in 2025 by 26- to 28 percent from 2005, doubling the pace of the current target. More remarkably, China vowed to turn around the increase in its carbon emissions by 2030 or sooner, promising to produce 20 percent clean energy by that date.
While the "handshake agreement" between the two presidents does not require legislative approval, the incoming Republican-controlled Congress could undermine efforts to meet the reduction targets. And a new president in 2017 will have the power to uphold the deal, or scuttle it, like President George W. Bush did with the Kyoto Protocols reached under President Bill Clinton.
On Wednesday, Speaker of the House John Boehner, Sen. Mitch McConnell, R-Ky., who is expected to take over as Senate majority leader, and Sen. Jim Inhofe, R-Okla., who is poised to become chairman of the Senate Environment and Public Works Committee, led the chorus of criticism from the right.
"This announcement is yet another sign that the president intends to double down on his job-crushing policies no matter how devastating the impact for America's heartland and the country as a whole," Boehner said Wednesday in a statement.
"And it is the latest example of the president's crusade against affordable, reliable energy that is already hurting jobs and squeezing middle-class families. Republicans have consistently passed legislation to rein in the EPA and stop these harmful policies from taking effect, and we will continue to make this a priority in the new Congress.
McConnell, whose re-election campaign in the coal-rich state of Kentucky often hinged on energy issues, slammed the agreement as "unrealistic."
"Our economy can't take the President's ideological War on Coal that will increase the squeeze on middle-class families and struggling miners," McConnell said in a statement.
"This unrealistic plan, that the President would dump on his successor, would ensure higher utility rates and far fewer jobs. The President said his policies were on the ballot, and the American people spoke up against them. It's time for more listening, and less job-destroying red tape. Easing the burden already created by EPA regulations will continue to be a priority for me in the new Congress."
Inhofe, meanwhile, is one of the loudest deniers of climate change on the Hill. But Wednesday, he focused not on the science driving the agreement, but rather the historic mistrust between the two nations.
"It's hollow and not believable for China to claim it will shift 20 percent of its energy to non-fossil fuels by 2030, and a promise to peak its carbon emissions only allows the world's largest economy to buy time," Inhofe said in a statement on Wednesday.
"China builds a coal-fired power plant every 10 days, is the largest importer of coal in the world, and has no known reserves of natural gas. The American people spoke against the President's climate policies in this last election. As we enter a new Congress, I will do everything in my power to reign in and shed light on the EPA's unchecked regulations."
Lack of effort from China, the world's biggest polluter, has been a key Republican argument against major climate regulations. And without an agreement from China and the U.S., the world's other major economies would be likely to follow suit.
But action from China would go a long way toward undermining that argument, something a majority of Americans would like to see, despite Republican victories at the ballot box last week: Even with a conservative electorate turnout, national exit polls found 58 percent of voters concerned about climate change.