He’s looking at an option to pull out of the historic agreement within a year.

Less than a week after Election Day, Donald Trump is already trying to figure out how he can pull the United States out of the historic Paris climate deal as quickly as possible.

Trump considers global warming a hoax, despite an overwhelming consensus from climate scientists who say that climate change is both real and man-made. Throughout his campaign, he promised to cancel the Paris climate agreement, which was signed by more than 180 countries last year and hopes to keep the world below 2° C of warming.

The possibility of a Trump presidency actually helped spur countries to ratify the agreement on an accelerated timeline, and the agreement officially went into effect on November 4.

But a source on his transition team told Reuters that the president-elect might be looking at a more extreme option to cancel the Paris agreement, by canceling the very treaty that made the Paris agreement possible in the first place — the United Nations Framework Convention on Climate Change (UNFCCC). The UNFCCC was ratified by the Senate under George H.W. Bush, and the United States was actually the first developed country to ratify it — largely because the U.S. felt it was important to have a seat at the table for climate negotiations on the international stage.

Beyond officially pulling out of the agreement, a Trump administration threatens to undermine the U.S. role as a leader on climate action simply because he has shown no interest in continuing President Obama’s progress — instead, he has bragged about his intention to cancel Obama’s signature climate regulations like the Clean Power Plan. So far, there’s nothing to show that his promises on the campaign trail won’t be carried out once he is president — he has already named Myron Ebell, a climate denier, to lead his EPA transition team (and there is speculation that Ebell could snag the role of top EPA administrator once Trump takes office).