Environmentalists hailed the deal while acknowledging that many of the details still need to be fleshed out.

Jake Schmidt, director of the Natural Resource Defense Council's international program, said the announcement sends a signal to other countries that China, long viewed as a roadblock in climate efforts, is taking efforts to reduce carbon emissions seriously.

The plan puts Chinese coal consumption on track to peak in about 2020, with carbon emissions maxing out a few years later, he said.

And it recasts the debate over climate change in the United States, where climate skeptics have long argued that American action was worthless without commitments from other countries, he said.

"The bogeyman has always been, 'What about China?" Schmidt said. "This takes that off the table."

Wyoming's Republican congressional delegation was quick to fire back. U.S. Sens. John Barrasso and Mike Enzi said the deal would hamstring the American economy by implementing carbon-cutting measures while helping China, which they said would not have to impose cutbacks until 2030.

Barrasso, in an interview, said the agreement will hurt Wyoming miners and ratepayers in the form of reduced coal demand and higher electricity bills.