A very senior administration official cautioned that Trump had not yet made a final decision and continued to weigh his options.
Another option, said University of California, Berkeley climate scientist Zeke Hausfather, would be for Trump to withdraw from the United Nations Framework Convention on Climate Change, the treaty on which the Paris accord was based, which would take only a year.
"Don't know which way Paris will go, but I've done all I can to advise directly to POTUS, through others in WH & via councils, that we remain", Musk tweeted to his 8.8 million followers on Wednesday, adding that he would "have no choice but to depart councils" if Trump did go through with the exit.
Almost 200 nations, including the United States under President Barack Obama's administration, agreed in 2015 to voluntarily reduce their greenhouse gas emissions in an effort to combat climate change.
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But CBS News confirms that the president has started to tell confidants he will withdraw from the agreement. If the country pulls out of the deal now, it could put the whole affair in jeopardy.
As the world's second-biggest polluter after China, a move by the U.S.to scrap the accord involving nearly 200 nations would pour hundreds of billions of tons of carbon dioxide into the atmosphere and speed up the warming trend already taking place.
News of Trump's expected decision drew swift reaction from the United Nations.
The back-and-forth in the Trump Administration over whether to stay part of the Paris agreement has triggered an outpouring of opinion and lobbying, perhaps most of all from corporate America, which has strongly supported the accord.
The U.S. set a target for reducing greenhouse gas emissions by 2025 at 26 to 28 percent below 2005 levels - or about 1.6 billion tons of annual emissions.
Juncker says European leaders tried to explain the process for withdrawing from the global agreement to Trump "in clear, simple sentences" during meetings last week.
Trump, who has called climate change a "hoax", will announce his decision on the Paris accord at 3:00 p.m. ET.
It takes at least a year and possibly up to 3½ years for a nation to withdraw from the pact.
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Musk is joining other corporate CEOs in a last-minute push to convince the president not to cede USA leadership on climate. On Wednesday afternoon, Trump was to meet with Secretary of State Rex Tillerson, who has favored remaining in the deal.
During their visit last week Pope Francis gave Trump a copy of his encyclical on climate change, which the president promised to read.
The only two countries not now supporting the deal are Nicaragua and Syria.
"A USA withdrawal would be the best outcome for worldwide climate action", he wrote recently. "And we got the whole world to join us", she said in a statement.
But President Donald Trump could rely on his executive powers to pull the USA out. They are among the most vulnerable to climate change, partly because in many countries they make up the larger share of the agricultural work force and partly because they tend to have access to fewer income-earning opportunities. These include carbon dioxide generated from burning of fossil fuels that scientists blame for a warming planet, sea level rise, droughts and more frequent violent storms.
Once in power, President Trump and Pruitt have moved to delay or roll back federal regulations limiting greenhouse gas emissions while pledging to revive long-struggling US coal mines.
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Andrew said he would like to thank his family, principal, teachers and friends for being so supportive during the entire process. In that round, Gabrielle had a brief conversation with the judge, according to National Spelling Bee blog.