He's long been a critic of climate science -- and now those words now loom over his decision.
Trump's long-held views on climate change and global warming include -- despite scientific evidence to the contrary -- suggesting climate change is a hoax that was perpetrated by the Chinese government.
During the 2016 campaign, for example, Trump said he would "rescind all the job-destroying Obama executive actions," including the Paris agreement.
Belief vs. Fact
Trump has long cast himself as someone who doesn't "believe" in global warming, suggesting that the scientific fact is a belief, not a fact.
"I'm not a believer in man-made global warming," he told Hugh Hewitt in 2015. "But the problem we have, and if you look at our energy costs, and all of the things that we're doing to solve a problem that I don't think in any major fashion exists."
The day after his announced his run for president in 2015, Trump told Fox News that he was "not a believer in man-made climate change" and faulted Obama for arguing that the issue is a top problem.
Trump's skepticism about the Paris Climate Accord stems, in part, from his idea that growing countries -- namely, China -- want the United States to enter into deals in an effort to stymie their growth.
Trump made this clear in 2012 when he flatly blamed global warming on "the Chinese."
"The concept of global warming was created by and for the Chinese in order to make U.S. manufacturing non-competitive," he tweeted.
And he has also said that climate change is a "hoax" carried about by the Chinese.
Trump, in 2010, reportedly told an audience at one of his golf courses that "China and other countries couldn't care less" about climate change.
China, though, signed onto the Paris agreement in 2016 and the President has tried to back away from his criticism of China on global warming and even flatly -- and inaccurately -- denied that he ever said it.
"And I often joke that this is done for the benefit of China. Obviously, I joke," he said on Fox News in January 2016.
Much of Trump's opposition to fighting climate change has stemmed from conspiracy theories that argue a whole host of people -- Democrats, scientists, foreign countries -- have fabricated climate science to sell the theory to the American people.
After "Climategate," a controversy regarding stolen emails between climate scientists that were published in 2009, Trump called climate change a "con" during a 2010 appearance on Fox News.
"In Washington, where I'm building a big development, nobody can move because we have 48 inches of snow," he said.
Trump has held onto these beliefs to years, too.
"They say they have science on one side but then they also have those horrible emails that were sent between the scientists," he said.
Trump has long linked extreme weather events -- ice storms, cold weather, large snows -- as proof that global warming is a "total, and very expensive, hoax."
In 2013, when an ice storm blanketed the Southern United States, he made the same case that the extreme weather proved global warming science wrong.
"Ice storm rolls from Texas to Tennessee - I'm in Los Angeles and it's freezing. Global warming is a total, and very expensive, hoax," he tweeted.
And on his final season of the NBC's "Celebrity Apprentice," which aired months before he announced his 2016 candidacy, Trump suggested that cold weather in New York proved climate change was wrong.
"Do you believe in global warming," he asked Gilbert Gottfried, who said yes. "And yet you are freezing your ass off."
Of course, scientists argue that one weather event can't be linked directly to global