Some of the stories that gripped our attention in 2014 will probably be forgotten in a few years — if not a few weeks. But there's one story that President Obama argues we'll be living with for decades to come.

"There's one issue that will define the contours of this century more dramatically than any other. And that is the urgent and growing threat of a changing climate," he said in September, addressing the United Nations Climate Change Summit.

Even as Obama struggled with other big challenges this year, climate was one area where he managed to get some traction.

As the threat of a changing climate became more obvious and immediate, governments here and around the world began to respond. In June, the Environmental Protection Agency unveiled new rules governing power plants — the No. 1 source of greenhouse gases in the U.S.

"2014 is the year in which a lot of these initiatives took form and became public. ... So this has been a big year," says David Doniger of the Natural Resources Defense Council. Doniger says those long-awaited rules are the centerpiece of the president's effort to fight climate change.

The administration has also taken steps to boost energy efficiency and promote cleaner sources of electricity that don't produce carbon pollution. None of that sits well with the coal mining industry that Luke Popovich represents as vice president of the National Mining Association.

"It's almost a jihad against fossil energy, but particularly focusing on coal. ... This is the electricity generation that you depend on for your air conditioning in the summer and your heat in the winter," Popovich says.

Obama's plan does call for significant cuts in greenhouse gases — cuts the president calls "ambitious but achievable." And he's not just focused on U.S. pollution. In November, Obama announced a landmark carbon-cutting deal with China — the world's leading producer of greenhouse gases.

"This is a major milestone in the U.S.-China relationship. And it shows what's possible when we work together on an urgent global challenge," Obama said.

The U.S.-China deal provided a jump-start for international climate talks, expected to culminate in Paris this coming year.

Critics complain that while the U.S. is already cutting its carbon pollution, China's emissions are allowed to keep growing until 2030. China is already making big investments in clean energy, though. And the Chinese government has announced plans to cap the use of coal within five years. Doniger of the NRDC says China's choking smog problem gives it a big incentive to clean up its power plants. What's more, he says, the Chinese government is genuinely worried by increasingly dry weather in the northern part of the country and rising sea levels in the east.

"They understand climate change is real. And when their scientists tell them it's real, they don't have a bunch of ideologues who tell them it's a hoax," Doniger says.

Obama's climate agenda is about to face new political headwinds, though. His announcement in China came just eight days after the midterm elections, which gave Republicans control of not only the U.S. Senate but also two-thirds of state legislative chambers. States are responsible for implementing the new EPA rules. And the mining association's Popovich says that could be the next climate battleground if some try to delay or thwart the administration's policy on power plants.

"It's going to come down to governors in two, three dozen states saying, 'You have to tear this up and start over again. We can't expose our citizens to these kinds of cost increases for so little benefit,' " he says.

EPA Administrator Gina McCarthy is not backing down. She points to polls showing that most Americans want the government to cut greenhouse gases, even if that means they have to pay a bit more for electricity.

"I feel very confident that the American people want EPA to continue to protect them and their family and most importantly their kids. ... They are worried about climate change. And they want us to do something. So I'll hopefully let democracy work," she told reporters in November.

One unexpected wrinkle in climate policy stems from the steep drop in oil prices. With gasoline now averaging less than $2.40 a gallon nationwide, demand for SUVs and pickup trucks has picked up, potentially undermining some of the gains of the administration's tougher fuel economy standards.

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