Senate Democrats encouraged President Trump to remain a part of the Paris Climate Agreement during a press conference on Wednesday.

The White House says the president has not made up their mind about staying in the agreement, but Senate Minority Leader Sen. Chuck Schumer, D-New York, said that the Trump administration is "leaning towards withdrawing the United States" from the pact.

In anticipation of the Group of Seven (G7) conference in Sicily this week, which will be President Trump's first appearance at an international summit, 40 Senate Democrats signed and sent a letter to the president urging him not back out of the international climate change agreement.

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The agreement was signed last year during Barack Obama's presidency at the COP21 conference in Paris, where nations committed to slowing the effects of climate change through cutting down on greenhouse gas emissions.

Earlier in May, Mr. Trump delayed a meeting on the Paris Climate Agreement, citing "scheduling conflicts" for the postponement. The White House has said the president will announce the United States' position on the agreement after the G7 conference.

Schumer warned that if the United States were to un-sign the agreement, all of the progress in combatting climate change "would be undone in one fell swoop."

The senators present referenced the urgency of addressing the effects of climate change and cited incentives for transitioning to renewable energy sources and away from fossil fuels, such as continued economic growth and job creation.

The group of Senate Democrats also said that U.S. participation in the climate agreement is key to American competition and leadership on the international stage, especially with regard to China.

"Imagine that: Donald Trump, who campaigned repeatedly that China was eating our lunch and taking our jobs, is willing to cede both economic and moral ground to China," Schumer said.

Scientists, business owners, even our kids know #ClimateChange is real. Our gov’t shouldn’t run away from it. #ParisAgreement — Chuck Schumer (@SenSchumer) May 24, 2017

If the Trump administration were to pull out of the pact, the U.S. would join just two other nations that have not signed the agreement.

"We would be joining Syria and Nicaragua," said Sen. Tom Carper, D-Delaware. "That's not a pleasant company for us to be in in regards to this issue."

Critics of the Paris Climate Agreement argue that the promise to cut greenhouse gas emissions by 26-28 percent is too steep of a promise and may jeopardize the U.S. economy. These critics argue that the United States should either back out of the agreement or go to the Senate for a vote. If the agreement did reach the Republican-controlled Senate for ratification, it would likely fail.

Sen. Sheldon Whitehouse, D-Rhode Island, also referenced a full page advertisement in the New York Times from 2009 signed by Mr. Trump, as well as his eldest daughter and White House Adviser Ivanka Trump, that urged then-President Obama and Congress to pass legislation combating climate change.

The Democratic senators warned that withdrawing from the agreement would be "a historic misstep," as Schumer put it.

"I urge the president to remain at the table and to exercise US leadership on this very important global issue," said Sen. Ben Cardin, D-Maryland, who is also a ranking member of the Senate Foreign Relations Committee.