In an announcement harkening to a characteristically reality TV cliffhanger, the president teased his decision in a tweet on Saturday morning during a summit with the Group of 7 industrialized nations in Italy, where the U.S. clashed with European allies over climate and trade. Trump initially delayed the decision until after the G7 meeting, which ended on Saturday.
European, Canadian and Chinese leaders have urged Trump to keep the U.S. in the accord. All but two countries ― Syria and Nicaragua ― signed the agreement committing to begin slashing planet-warming emissions.
The accord is not legally binding. And even if every country reached its promised goals, the targets set out in the agreement would not prevent the Earth from warming beyond the 3.6 degrees Fahrenheit above pre-industrial levels, after which scientists predict the most catastrophic effects of climate change would become irreversible. But the United Nations-brokered deal marked the first time the world, including the U.S. and China, the biggest polluters by far, agreed to slash emissions with the intent of halting global warming.
Still, Trump pledged to "cancel" the agreement during his openly nationalist presidential run last year, insisting multilateral deals like it were harmful to U.S. economic interests. In March, he ordered the Environmental Protection Agency to review the Clean Power Plan ― the only U.S. policy for cutting emissions from the electricity sector. Without this sweeping regulation, which puts limits on coal-fired power plants and encourages the proliferation of renewable energy, the U.S. won't even come close to meeting its emissions goals.
"It seems President Trump is seeking to build the kind of suspense that is usually reserved for reality shows," Heather Coleman, climate and energy director at the charity giant Oxfam America, told HuffPost by email on Saturday morning. "Climate change is not a TV show, it is and will continue to have devastating consequences for all of us on this planet, especially the poorest and most vulnerable among us."
The White House has split over the future of the Paris Agreement. Like climate science itself, which Trump has dismissed as a "hoax", the pact has overwhelming support. Sixty-one percent of Americans said the country should remain in the deal, while just 17 percent support withdrawing and 21 percent weren't sure, according to a HuffPost/YouGov poll conducted last week. Already, more than 400 U.S. cities, 37 states, 800 universities and nearly half of all Fortune 500 companies have set clean energy and emissions targets.
Secretary of State Rex Tillerson, Energy Secretary Rick Perry and familial advisers Jared Kushner and Ivanka Trump back the deal. Big corporations, including coal, oil and gas companies, also support remaining in the agreement.
EPA administrator Scott Pruitt and White House chief strategist Steve Bannon want to pull out of the pact. Aside from the usual cadre of once-fringe climate science deniers, they are joined by a handful of House Republicans and at least three GOP senators.
Sources told HuffPost this month that Trump was leaning toward withdrawing. But since then, world and corporate leaders have increased pressure for the U.S. to remain in the deal. During his first visit to the Vatican this week, Pope Francis gave Trump a 184-page letter on climate change.
In the president's best-known business book The Art of the Deal, he outlines a strategy for negotiating based on making aggressive opening salvos. Vowing to withdraw could be an initial step toward reworking the Paris Agreement to get what his administration considers more favorable terms.
Pulling out of the agreement could have major economic consequences. The U.S. could lose jobs in a clean energy industry estimated to be worth $6 trillion by 2030. Countries could put a tariff on American-made imports. And investors could sour on the U.S. amid what they see as instability sown by sclerotic regulation of carbon emissions.
The diplomatic ramifications could be worse. Quitting the deal could brand the nation as a "rogue country" and a "climate pariah" as it loses its seat at the negotiating table on global climate policy. Moreover, the U.S. risks ceding global influence to rival superpower China, which has already promised to support poorer countries' efforts to adapt to climate change.
"Trump has heard now very clearly from world leaders, CEOs, and even the Pope," David Waskow, director of international climate policy for the World Resources Institute, told HuffPost by email. "It's time for him to make the right decision."