Republicans have warned that US President Barack Obama's deal with China to curb greenhouse gas emissions would face stiff opposition in congress.
In signing the landmark agreement with his counterpart Xi Jinping in Beijing, Obama infuriated his opponents, who are angry with the president for circumventing congress by issuing executive orders.
"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," House Speaker Boehner said on Wednesday.
"It is the latest example of the president's crusade against affordable, reliable energy that is already hurting jobs and squeezing middle-class families."
Boehner was joined by Senate Republican leader Mitch McConnell, who said he was "particularly distressed" by the deal, which has been widely seen as a breakthrough in co-operation on climate change between the world's two biggest polluters.
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China set a target for its greenhouse gas output to peak "around 2030", the first time Beijing agreed to an approximate target date for beginning to reverse its emissions trend.
Obama set a goal for the US to cut such emissions by 26-28 per cent from 2005 levels by 2025.
"I read the agreement requires the Chinese to do nothing at all for 16 years while these carbon emission regulations are creating havoc in my state and other states around the country," said McConnell, who is from the coal-rich state of Kentucky.
The reactions were the first salvos in the coming battle in the US Congress, where Republicans will assume control of both chambers on January 3, having emerged on top in last week's midterm elections.
Outgoing Senate majority leader Harry Reid hailed the US-China pact as one that could "spur other countries" to join in combating climate change.
But in Washington, a monster fight looms ahead.
Boehner noted that the House of Representatives has passed several bills to "rein in" Environmental Protection Agency regulations on carbon emissions and other energy issues.
The legislation stalled in the Democratic-held Senate, but with Republicans taking over, energy legislation may be reaching Obama's desk next year.
McConnell, asked whether he will move to reverse EPA rules on emissions, said: "We'll be discussing all that with our colleagues here in the next few days."
Joining the new Senate will be Iowa Republican Joni Ernst, who has called for the EPA's elimination.
And the Senate environment and public works committee will likely be headed by Senator James Inhofe, seen by many as the leading climate change sceptic in congress.
Inhofe, who has declared man-made global warming a "hoax", is sure to attempt to eviscerate Obama's proposed EPA regulations on power plant emissions.
On Wednesday, he dismissed the US-China deal as "a non-binding charade" and vowed to go after Obama's "overbearing" EPA mandates.
"As we enter a new Congress, I will do everything in my power to rein in and shed light on the EPA's unchecked regulations."
Energy policy is a Republican priority for congress next year and gaining approval to construct the long-delayed Keystone XL pipeline between Canada and the United States will be an early goal.
But the White House, seeking to avoid the gridlock on Capitol Hill, has chosen to act at the regulatory level.
After the bitter experiences of the Kyoto Protocol which the US signed but never ratified, and fruitless negotiations in Copenhagen, congress was unprepared to pass a climate bill, let alone ratify a legally-binding international treaty.
Obama has used the EPA and its publication of strict environmental standards to further reduce CO2 emissions, particularly after his 2012 re-election.
