The Paris climate agreement, a historic international treaty to curb global greenhouse gas emissions, has only been in effect for 12 days. But if President-elect Donald Trump follows through on his campaign promise to "cancel" the agreement, America's participation in the pact could be halted before it begins.
In the wake of the election, there's been a lot of speculation as to what could happen if the US reneges on their promise. Like all presidents before him, not everything Trump promised on the campaign trail will come to pass. But when a man who has said climate change is a hoax created by the Chinese government (a comment he later said was a joke) is elected to the White House, you might want to take his stated intentions on a major climate agreement seriously.
But can he even do that? And if he did, what would that mean for the US, and the planet?
The first answer is yes, Trump can decide the US will not fulfill its part of the pact
"The Paris agreement is really a collection of individual pledges by countries on what they're willing to do to cut their emissions," said Ann Carlson, a professor of environmental law and faculty co-director of the UCLA Emmett Institute on Climate Change and the Environment at the UCLA School of Law. "So it's quite easy for the US to decide that it's not going to live up to its commitments."
In signing the agreement, each country set its own plan—called a nationally determined contribution—that indicated how it would contribute to the overall goal of reducing emissions and stopping rising global temperatures. The US's statement included the Environmental Protection Agency's Clean Power Plan and new fuel efficiency standards for vehicles. President-elect Trump has already starting making plans to dismantle the EPA and tear up the Clean Power Plan, which would alone signal the US's reneged support for the agreement because we simply wouldn't be fulfilling our end of the bargain. But Trump could take things even further.
Formally leaving the Paris Agreement altogether is a bit harder
"To actually withdraw from the treaty is a much more involved process: the US would give notice and it would take four years before it could legally withdraw," Carlson explained.
And Trump could take things to the extreme
"The third option, and what I think is the most dramatic and really a strong signal to the international community that the US has no interest in being involved in global efforts to reduce greenhouse gases is to withdraw from the Framework Convention on Climate Change."
The Framework Convention on Climate Change is a United Nations agreement that was adopted in 1994 and has served as the basis for all of the international climate work since then. If the US formally withdrew from that Convention, it would be a very powerful and dramatic signal that this country has no interest in fighting global warming now or in the future.
The world won't end if the US decides not to participate.
Even if any of these three options comes to pass—the US shirks its Paris Agreement responsibilities, formally withdraws, or abandons the Framework Convention—the Paris Agreement would still survive.
To go into effect, the treaty required at least 55 countries representing 55 percent of the global greenhouse gas emissions to ratify their pledge to participate. We currently have 110 nations representing 77 percent of global emissions. Though the US represents a whopping 17 percent of global emissions, its exit wouldn't drop the participation below that threshold. It would, however, hold back the progress the agreement was created to accomplish.
But that doesn't mean there would be no consequences.
At the UN's global warming summit, many diplomats have stated concern over the President-elect's position. French presidential candidate Nicolas Sarkozy has proposed introducing a carbon tax on all US products imported to Europe if America withdraws from the agreement.
There's also the question of a domino effect: if the US leaves, will other countries follow? Carlson told me that's difficult to predict, but a US exit could actually strengthen some other countries' resolves.
"There are some strategic reasons that a country like China might want to do that," Carlson explained. "It has invested heavily in trying to shift to a cleaner, greener economy. It has domestic political pressure to reduce air pollution. China, I think, wants to be seen on the global stage as a leader."
Climate change, and the US's contribution to the fight against it, is going to be one of the first and most persistent topics that President-elect Trump will need to consider throughout his administration. That's why it's important to understand how his decisions would affect the country and the planet, even before we know for sure what he will do.
Get six of our favorite Motherboard stories every day by signing up for our newsletter.