President Barack Obama is planning to impose tougher than expected cuts on greenhouse gas emissions from US power plants, White House officials have said.
A year after proposing unprecedented carbon dioxide limits, the Obama administration was poised to finalise the rule at a White House event on Monday.
The president called it most significant step the US has ever taken to fight global warming.
Obama, in a video posted to Facebook, said the limits were backed up by decades of data and facts showing that without tough action the world will face more extreme weather and escalating health problems like asthma.
“Climate change is not a problem for another generation,” he said. “Not anymore.”
In his initial proposal, Obama had mandated a 30% nationwide cut in carbon dioxide emissions by 2030, compared to 2005 levels.
The final version, which follows extensive consultations with environmental groups and the energy industry, will require a 32% cut instead, according to Obama administration officials, who were not authorised to comment by name and requested anonymity.
Opponents said they would sue the government immediately. They also planned to ask the courts to put the rule on hold while legal challenges play out.
The final version also gives states an additional two years – until 2022 – to comply, yielding to complaints that the original deadline was too soon. States will also have until 2018 instead of 2017 to submit their plans for how they intend to meet their targets.