Michael Grunwald is probably right about the main reason for Donald Trump pulling out of the Paris Accord:
Donald Trump’s decision to withdraw from the Paris climate agreement was not really about the climate. And despite his overheated rhetoric about the “tremendous” and “draconian” burdens the deal would impose on the U.S. economy, Trump’s decision wasn’t really about that, either. America’s commitments under the Paris deal, like those of the other 194 cooperating nations, were voluntary. So those burdens were imaginary.
No, Trump’s abrupt withdrawal from this carefully crafted multilateral compromise was a diplomatic and political slap: It was about extending a middle finger to the world, while reminding his base that he shares its resentments of fancy-pants elites and smarty-pants scientists and tree-hugging squishes who look down on real Americans who drill for oil and dig for coal. He was thrusting the United States into the role of global renegade, rejecting not only the scientific consensus about climate but the international consensus for action, joining only Syria and Nicaragua (which wanted an even greener deal) in refusing to help the community of nations address a planetary problem. Congress doesn’t seem willing to pay for Trump’s border wall—and Mexico certainly isn’t—so rejecting the Paris deal was an easier way to express his Fortress America themes without having to pass legislation…
This also plays into his delusions that he can make better deals.
The actual facts don’t matter. MIT officials said that Donald Trump misunderstood the their research when he cited it as a reason for pulling out. The reality is that Donald Trump was searching for statistics he could twist to support the view he had already decided upon, and did not care about the research.
Glenn Kessler cited several factual errors in Donald Trump’s statement. Of course that is nothing new. It would be news if Trump got the facts right. Foreign Policy has more on Why Abandoning Paris Is a Disaster for America. I would recommend reading these articles as opposed to trying to summarize here.