When Americans hit voting booths on Nov. 8, one constituency will be watching nervously from thousands of miles away – climate change negotiators at the United Nations conference that begins a day earlier in Marrakesh.
The United States election holds major repercussions for the international climate regime. Diplomats in Morocco will huddle for its first convention after securing a landmark global agreement to ramp down emissions last year, and its success rests heavily on who will lead the US.
The top candidates offer two divergent paths: Democratic nominee Hillary Clinton would keep the US involved in the agreement inked last year in Paris and work on measures to realize President Obama's goal of curbing national carbon emissions at least 26 percent by 2025. Republican candidate Donald Trump has threatened to pull America out of the agreement, removing significant US leadership on the issue while also jeopardizing reductions from the world’s second-largest emitter (behind China).
With Clinton, leaders across the world largely know what they’re getting in the climate arena – an extension of Obama-era policies. Trump, meanwhile, has campaigned on yanking the US from the Paris agreement, which aims to slash emissions enough to prevent global temperatures from rising 2 degrees Celsius above preindustrial levels by 2100.
So what, exactly, would that look like?
Trump could follow three general paths: Withdraw from the agreement; pull out of the entire UN climate process, known as the UN Framework Convention on Climate Change; or, simply, do nothing to honor the commitment Obama made last year.
Trump's energy adviser, Rep. Kevin Cramer (R) of North Dakota, previewed an idea for delegitimizing the Paris agreement during a Tuesday debate with Clinton adviser Trevor Houser. Congressman Cramer said Trump would send the climate agreement through the Senate. There, it surely wouldn’t garner two-thirds majority needed to confirm a new, binding agreement.
"The point would be to have it fail,” says David Hunter, a law professor and Director of the International Legal Studies Program at American University Washington College of Law, though he questioned whether even that option was available once the agreement enters into force on Nov. 4.
Such a move would be largely symbolic, mainly because international environmental law experts say the Paris agreement doesn’t require that Senate step. (The Obama administration has gone by that logic, to the infuriation of Senate Republicans.)
But even symbolic measures can have real-world consequences – former President Bill Clinton backed off the Kyoto Protocol, another climate agreement struck in 1997, after the Senate voiced its disapproval in a 95-0 resolution. Trump could therefore potentially use the vote against the Paris agreement as pretext for withdrawing from the arrangement altogether, though he’d likely face an international haranguing as a result.
Even without all that procedure, Trump’s most effective play might be to simply do nothing.
Under the Paris agreement, the 26-percent emission reduction Obama floated is non-binding – if the US doesn’t meet that mark, there are no legal ramifications. Only the review and monitoring mechanisms for emissions cuts are legally binding, a structure to which the Senate gave its “advice and consent” under a previous climate agreement.
"That would be a good strategy for him if he didn’t want to make any political noise by withdrawing,” Mr. Hunter says. “Simply not take the steps necessary to meet the US (nationally determined contribution) and then submit a weak or meaningless plan the next time.”
After all, the Obama administration didn’t seek legally binding emissions cuts – as the European Union and some other countries preferred early in the process – precisely because he would have needed to run it through a hostile, Republican-controlled Senate.
"As long as the US did comply with the binding obligations, such as reporting on emissions, that course of conduct would arguably be consistent with the letter of the agreement, although certainly not with its spirit,” says John Knox, an international law professor at Wake Forest University and UN Special Rapporteur on Human Rights and the Environment.
That approach, however, might actually run afoul of the Paris agreement, argues Daniel Bodansky, a law professor and co-director of the Center for Law and Global Affairs at Arizona State University. He says that’s because the pledge each party makes is one “intends to achieve” and to "pursue domestic mitigation measures.”
“So if President Trump were to do nothing, then arguably that would breach US obligations under the Paris Agreement, as well as the obligation under the 1992 Framework Convention on Climate Change, which the Senate unanimously approved,” Bodansky says.
What that leaves a theoretical Trump White House are the two exit strategies of scrapping the agreement or the entire UN process.
The US can’t officially leave the Paris agreement until Nov. 4, 2020. That’s because countries cannot signal they want to withdraw until it has been in force for three years, and the actual removal takes one year. That would come just in time for a hypothetical Trump re-election bid, Knox notes.
But there’s also “a shortcut,” Knox says, which is to exit the UNFCCC entirely. That would be "an even bigger rejection of the international climate regime,” but he says, "the Trump administration could withdraw from the UNFCCC immediately after taking office, and be out of both agreements on the morning of Jan. 20, 2018.”
Even whether that is possible, however, is not entirely clear since the Senate already ratified the UNFCCC, says Kal Raustiala, a law professor and director of the UCLA Burkle Center for International Relations.
“There is a constitutional question, unresolved, about whether the president can withdraw from treaties duly ratified by the Senate without the Senate approving that withdrawal,” he says.
Despite the lack of constitutional clarity, Raustiala says many experts believe a president can unilaterally exit treaties. He points to former presidents Jimmy Carter scrapping a mutual defense treaty with Taiwan in 1979 and George W. Bush ending an antiballistic missile pact with Russia.
While all these options are on the table, some climate experts voice confidence that even a potential Trump White House would remain engaged.
“The issue of climate change has really entered the mainstream in diplomacy,” David Waskow, director of the World Resources Institute’s international climate initiative, said in a recent call with reporters. “This is very much bound up in a broader diplomatic context, international relations context.”
The UN's top climate change official, similarly, says the Paris accord has built considerable traction.
“I think everyone in the world is following the election process because of the implications, and we are vigilant, but it’s important to bear in mind the Paris Agreement has an incredible amount of legitimacy,” the UN's Patricia Espinosa told Climate Home.