The election of a U.S. president who has called global warming a “hoax” raised questions Wednesday about America’s involvement in the Paris Agreement on climate change — and the future of the deal itself.

As the sun rose over the Atlas mountains, news of Trump’s victory was still sinking in at U.N. climate talks in Marrakech, Morocco, where delegates from almost 200 countries — including the U.S. — were meeting for the first time since the landmark deal entered force.

The first official reaction came from an alliance of small island nations who fear they will be washed away by rising seas. In a diplomatically worded statement, Maldives Energy Minister Thoriq Ibrahim, who chairs the alliance, congratulated Trump and said his administration will have to confront the challenge of climate change and the transition to cleaner energy.

“America has led this technological transformation and can continue to create jobs and opportunity in this area – something people everywhere will benefit from,” Ibrahim said.

Environmental activists were devastated by the election result, with May Boeve, leader of the 350.org environmental group, calling it a “disaster.”

“Trump will try and slam the brakes on climate action, which means we need to throw all of our weight on the accelerator,” Boeve said. “In the United States, the climate movement will put everything on the line to protect the progress we’ve made and continue to push for bold action.”

In contrast to Barack Obama, who made climate change a key policy area, Trump has called global warming a “hoax” on social media and pledged in May to “cancel” the Paris deal, which was adopted in the French capital last year.

More than 100 countries, including the U.S., have formally joined the agreement, which seeks to reduce emissions of climate-warming greenhouse gases and help vulnerable countries adapt to rising seas, intensifying heat waves, the spreading of deserts and other climate changes.

The withdrawal process would take four years — an entire presidential term — under the terms of the agreement. However, Trump could also decide to simply ignore the Obama administration’s Paris pledge to reduce U.S. emissions by 26-28 percent from 2005 levels by 2025. The pledges are self-determined, and there is no punishment for countries who miss their targets.

It’s unclear what would happen to the deal if the U.S. dropped out, though U.S. negotiators and others said before the election they believed the rest of the world would go ahead because they see a transition to clean energy in their national interests.

“It seems like a most miserable U.S. election result for climate stewardship prospects,” said Jason Box, a glacier expert at the Geological Survey of Denmark and Greenland. “Can the world do climate stewardship without the U.S.? It has to.”

The conservative American Energy Alliance welcomed Trump’s victory, saying American people are tired of their interests taking a back seat to special interests in Washington.

“President-elect Trump’s victory presents an opportunity reset the harmful energy policies of the last generation,” said the group’s president, Thomas Pyle. “He has laid out an energy plan that puts the needs of American families and workers first.”