WASHINGTON (CN) – Fulfilling one of President Donald Trump’s campaign pledges and putting the future of a landmark environmental deal firmly on the 2020 presidential ballot, the White House on Monday formally notified the United Nations it plans to withdraw from the Paris climate agreement.

The move comes more than two years after Trump announced the United States intended to withdraw from the landmark accords, which were signed under former President Barack Obama. The U.S. will officially leave the pact next year, just after the 2020 presidential election.

“We will continue to work with our global partners to enhance resilience to the impacts of climate change and prepare for and respond to natural disasters,” Secretary of State Mike Pompeo said in a statement announcing the formal withdrawal. “Just as we have in the past, the United States will continue to research, innovate, and grow our economy while reducing emissions and extending a helping hand to our friends and partners around the globe.”

The agreement required signatories to stay in for a minimum of three years, meaning Monday marked the earliest the United States could back out, though Trump announced in June 2017 his administration would be pulling the country out of the deal.

Under the agreement, which Trump roundly criticized both on the campaign trail and in the White House as a danger to the U.S. economy, the almost 200 signatory countries set their own targets to curb greenhouse gas emissions. Countries will revise their plans every five years, with the intent of each being more ambitious than the last.

The United States had set a target of reducing emissions by 26 to 28% by 2025, relative to 2005 levels.

The international pact, which is nonbinding, aims to stave off further warming of as much as 1.8 degrees Fahrenheit.

Environmental groups denounced the formal withdrawal on Monday.

“Climate change won’t be solved without a global effort,” Mitch Bernard, president of the Natural Resources Defense Council, said in a statement. “It won’t happen without U.S. leadership. It won’t happen as long as the world’s second-largest climate polluter is backsliding on the climate pledge it has made to the rest of the world.”

Steve Herz, a senior international policy advisor at the Sierra Club, said in an interview Monday the impacts of the Trump administration’s formal withdrawal may be somewhat limited, considering other countries have been planning for the move since the last presidential election.

He also noted if a Democrat wins the White House in 2020, the United States would likely only be formally out of the agreement for a matter of months. It would take a Democratic president 30 days to rejoin the agreement, meaning the United States could be back in as soon as February 2021.

If they rejoined the agreement with a more ambitious emissions reduction plan than before, it could make the previous four years of uncertainty less damaging in the eyes of other countries, Herz said.

“We’ll lose the opportunity to lead in this process, but we will be able to catch up in terms of our own revised pledge,” Herz said.

Still, he said it could impact the ability of the United States to take a leading role on the issue of climate change, particularly on priorities like transparency, as countries could approach future negotiations with concerns about what happens the next time a president of the opposing party sweeps into the White House.

Erika Rosenthal, a staff attorney at Earthjustice, was similarly optimistic that the Paris agreement will remain viable without the United States, saying in the absence of federal action, businesses and state and local governments have already been moving to meet the emissions reductions goals the United States set.

“I think the Paris agreement will move forward, the real question for the Unites States will be one – the extent to which all these other entities can keep the United States on track to keep its Paris commitment, but also two – how quickly we can get back into it,” Rosenthal said in an interview.