So the U.S. and China Made an Historic Climate Agreement. Now What?

When the White House announced late Tuesday evening that the U.S. and China struck an agreement to mutually shrink their greenhouse gas emissions, news media and policy analysts reacted with surprise. After decades of a logjammed "you first" approach to climate policy, the presidents of the world's two biggest emitters appeared at a press conference Wednesday all smiles. The U.S., President Obama said, would nearly double its prior emissions target, setting new goals of emitting 26 percent to 28 percent less greenhouse gases by 2025 than the baseline set in 2005. China, meanwhile, agreed to hit an emissions "peak" by 2030 and taper emissions downward from there.

The political significance of this is hard to overstate, say experts in climate and environmental law. First, the agreement will deprive chronically hesitant nations of a central excuse for their inaction on climate change.

"It makes it much more difficult for other countries not to participate" meaningfully in the upcoming 2015 climate negotiations in Paris, says Jonathan Cannon, a professor of law at the University of Virginia who served as general counsel to the Environmental Protection Agency (EPA) during the Clinton administration. "Before, other countries could say that the two biggest emitters aren't stepping up to the plate. Now, it appears they are."

Second, it may also serve to reinforce the staying power of Obama's new clean power plant rules in the face of a rising GOP. The rules, which have yet to be finalized as the president's second term draws to a close, are still likely to be subjected to relentless Republican challenges, and the possibility of a challenge reaching the Supreme Court looms large. Yet the regulations are necessary for the U.S. to meet its new, internationally paraded emission targets. That fact might defend the rules from their critics.

"I think that the president has just signaled to Congress that the EPA action that he's taking to regulate existing power plants is the centerpiece to reducing emissions consistent with the Chinese agreement, and they have to keep their hands off of it. He's made it more difficult for the Republicans to curtail that rule," says Ann Carlson, a co-director of the Emmett Institute on Climate Change and the Environment at the University of California Los Angeles law school.

The fact that successful headway on the agreement will rest in part on reducing emissions from new and existing U.S. power plants could also make it "much less palatable" for the Supreme Court to move to diminish the new rules. If "facts on the ground" have the power to influence Supreme Court decisions, the reality of a historic and internationally applauded agreement hinging on the implementation of the rules could do much to color the court's verdict.

China, for its part, is facing embarrassingly poor air quality and has "powerful domestic reasons to reduce coal use," says Michael Gerrard, the director of the Sabin Center for Climate Change Law at Columbia University. Gerrard says China is not in a position to bow out of this agreement. "The pollution is choking their cities and leading to hundreds of thousands of premature deaths."

For all its political significance, without a formal structure of accountability, the agreement remains just that: a public agreement between two powerful executives. And if China hesitates to make progress toward its new emissions targets, the U.S., fearing competitive disadvantage, might be more reluctant to go forward with its own emissions cuts, sparking a feedback loop of inaction that China especially cannot afford.

"It would be detrimental to China and the rest of the world. If China is serious about reducing climate change, it has to depend on us as well as other countries in order to achieve its goals," says Cannon. "There are consequences for making agreements with important partners and not performing. Those consequences are not necessarily legal. They could come in all sorts of forms."

Despite its historic political implications, the agreement's effect on the future of global climate change is woefully inadequate, experts say.

Greenhouse gas cuts to the tune of 26 percent to 28 percent below 2005 levels may sound like large figures. But in the context of the Kyoto Protocol, and the Intergovernmental Panel on Climate Change recommendations, measuring from 2005 levels is something comparable to grade inflation. The year 1990 has been upheld as the international baseline for emissions reductions, and it is the baseline used by the European Union in its recent commitment to reduce emissions by 2030 to a whopping 40 percent below 1990 levels.

When Wil Burns, a professor of international environmental law at American University, read the news of the U.S.'s commitment, he decided to crunch the numbers. The plan to cut emissions to around 26 percent to 28 percent below 2005 levels would actually only be a 10 percent to 14 percent reduction below 1990 levels. Compared with the European commitment, the U.S. commitment is dangerously minute.

"One of the games that countries play when they talk about reducing their emissions is moving the goal post," says Burns. "When they say they're going to reduce emissions by a certain amount, you want to look at how far from 1990 levels they are measuring."

Failure to make further, more immediate cuts to emissions leaves us likely bypassing several irreversible climate "benchmarks," including the oft-cited two degrees Celsius of global warming. But given the political environment of stagnation and a global economy still thoroughly reliant on fossil fuels, many experts feel the U.S.-China agreement is the best possible outcome, for now.

"From the perspective of the climate, this announcement is still bad news. But from the perspective of politics, having U.S. and China hand in hand in this is remarkable," says Douglas Kysar, a professor at Yale Law School.