Governors' Wind Energy Coalition

WASHINGTON — All but giving up on Congress, as spent the year foraging for issues he could tackle on his own, and largely coming up with minor executive orders. But on Monday, he will unveil a n to take on that may be his last, most sweeping effort to remake America in his remaining time in office.

WASHINGTON — All but giving up on Congress, President Obama has spent the year foraging for issues he could tackle on his own, and largely coming up with minor executive orders. But on Monday, he will unveil a plan to take on climate change that may be his last, most sweeping effort to remake America in his remaining time in office.The far-reaching regulations will for the first time force power plants in the United States to curb the carbon emissions that scientists say have been damaging the planet. By using authority already embedded in law, Mr. Obama does not need Congress — so, in this era of gridlock, he has a chance to transform the nation’s energy sector and, at the same time, his presidency.

While the administration was still completing crucial elements of the plan, it was already clear that the economic stakes are enormous. The new regulations could eventually shutter hundreds of coal-fired power plants. Critics wasted little time arguing that the president’s unilateral plan abuses his power in a way that will cost jobs and raise energy prices for consumers.

“The administration has set out to kill coal and its 800,000 jobs,” Senator Michael B. Enzi, Republican of Wyoming, the nation’s top coal-producing state, said in response to Mr. Obama’s Saturday address. “If it succeeds in death by regulation, we’ll all be paying a lot more money for electricity — if we can get it. Our pocketbook will be lighter, but our country will be darker.”

Almost by default, climate change looks to be the defining domestic initiative of Mr. Obama’s second term. His aspirations to enact gun control measures, pass a jobs plan, overhaul the tax code and reach a grand bargain on long-term spending all have eluded him amid Republican opposition. He may yet negotiate legislation liberalizing immigration policy, but otherwise harbors little hope for major new domestic action.

In taking on climate change, Mr. Obama is returning to one of the themes of his first campaign for president, when he vowed that his election would be remembered as the moment when “our planet began to heal.” His difficulties living up to that rhetoric has deeply frustrated many supporters, and he personally urged his Environmental Protection Agency chief, Gina McCarthy, to draft an ambitious regulation in time to ensure that it is finalized before he leaves office.

“It’s the most significant executive action he can take probably in the entirety of his presidency,” said Neera Tanden, president of the left-leaningCenter for American Progress. “The president is a relatively young president,” she added. “Not to do something would be something you wouldn’t want to live with for the next few decades.”

Having failed to pass climate legislation through the Senate in his first term, Mr. Obama has used his own power to advance his goals, including increased fuel-efficiency standards for cars and trucks. In seeking to limit power plants, he is finally addressing the most significant source of carbon pollution.

And yet the president seems to have chosen a low-wattage rollout of the plan. He will not unveil it in a televised East Room address or travel to some out-of-town venue for a big speech, as he has for moves of far less import. Instead, he will leave it to Ms. McCarthy to announce on Monday, while he plays a supporting role by making a telephone call to the American Lung Association.

That may reflect the complicated politics of the issue. Republicans are not the only ones concerned about economic costs, or for that matter political ones. Democrats from coal-producing states are acutely nervous with midterm elections approaching.

Representative Nick J. Rahall II, Democrat of West Virginia, for one, has already distanced himself from the plan. “I will oppose this rule as it will adversely affect coal miners and coal-mining communities throughout West Virginia and the nation,” he said.

White House officials denied playing down the announcement and said they were trying to be creative because an East Room event is no longer as useful as it once was. They are trying to frame the issue as a matter of public health. To tape his Saturday address, Mr. Obama traveled toChildren’s National Medical Center in Washington to visit children with asthma aggravated by air pollution.

While studies show climate change may exacerbate respiratory diseases, that is hardly the most significant impact of global warming. But the White House hopes that focusing on sick children will play better politically than sweeping statements. An April Gallup poll found that one in four Americans is skeptical of the science of global warming.

The new regulation, which must go through a period of public comment before taking effect, will set a national standard to cut carbon from power plants. It will offer states a menu of options to achieve those cuts, such as adding wind and solar power and energy-efficient technology and joining or creating state-level emissions trading programs called cap and trade.

In 2012, the United States emitted 6.5 billion metric tons of greenhouse gases, of which two billion came from power plants, most burning coal. Experts close to the drafting of the rule said they expected it would lead to annual cuts of up to 500 million tons of carbon in the next decade and more than one billion tons of carbon annually in ensuing years.

But as recently as last week, according to people close to the process, officials had not decided which year to use as the baseline for determining cuts. The coal industry has pushed for 2005, when emissions were near their peak, while environmentalists want a baseline of 2012, when they were lower, meaning that cuts would have to be deeper.

By using the existing Clean Air Act, Mr. Obama will not be able to go as far as new legislation, which would have affected the entire economy. “It would have been better to get more done, absolutely,” said Carol Browner, the president’s former environmental adviser. “But if you can’t get there, using existing law to look at things on a sector basis is a very smart move.”

The new rule will be announced hours before Mr. Obama leaves for Europe, where leaders have pressed him to be more assertive on climate change. “By increasing our credibility with this rule, we leverage everybody else and put the president back in a leadership position,” said Durwood Zaelke, president of the Institute for Governance and Sustainable Development, a research organization. “He becomes seen as a climate leader.”