By Alissa de Carbonnel and Valerie Volcovici
BRUSSELS/WASHINGTON (Reuters) - EU officials are scrambling to persuade U.S. President Donald Trump not pull out of the Paris climate accord after his advisers warned of legal problems if Washington stayed in but lowered its commitments.
European Union sources said European ministers and EU officials have been lobbying senior White House staff after hearing Trump was leaning heavily towards exiting the global pact because of the legal problems that could arise if Washington revised its climate commitments downward.
Trump is expected to announce a decision as early as next week along with other energy policy changes, including ordering opening up LNG exports and Arctic drilling.
"If the biggest economy in the world dumps the whole thing ... we all have to worry," one EU source told Reuters. "We are reaching out at all possible levels ... to try to explain why they do not need to leave the Paris agreement."
Four U.S. sources briefed on White House meetings, who asked not to be named, told Reuters on Tuesday that opponents of the 2015 accord to cap greenhouse gas emissions had won the upper hand in recent days about whether to pull out or remain in the accord with a reduced commitment.
Senior administration officials - including chief of staff Reince Priebus, chief strategist Steve Bannon, White House Counsel Donald McGahn and Environmental Protection Agency head Scott Pruitt - argued Washington risked legal challenges if it lowered its climate goals while remaining a party to the deal.
The sources said White House lawyers had argued in a memo recently that changing the U.S. target, known as the Nationally Determined Contribution, could trigger these complications.
A White House spokeswoman said a decision had not yet been made, and gave no further details. Trump said at a rally in Harrisburg, Pennsylvania on Saturday that he would announce a "big decision" on the Paris agreement within two weeks.
EU Climate Commissioner Miguel Arias Canete, who has telephoned White House officials to press them on the climate issue, said "there is room for the new U.S. administration to chart its own path."
"We all continue to hope the U.S. will find a way to remain within the Paris Agreement," he told reporters after a meeting with Iran's environment minister in Tehran on Sunday.
Trump vowed during his campaign to "cancel the Paris Climate Agreement" within 100 days of becoming president, part of a broader plan to sweep away Obama-era environmental protections he said were hobbling the economy.
But since being elected, he has been mostly quiet on the issue. Scores of large U.S. companies and several Republican lawmakers have urged him to keep America in the deal as a way to protect American industry interests overseas.
The accord, agreed by nearly 200 countries in Paris in 2015, seeks to limit planetary warming by cutting emissions of carbon dioxide and other gases from burning fossil fuels.
The United States committed to reducing its emissions by between 26 percent and 28 percent below 2005 levels by 2025 - a level that the Trump administration is unlikely to support.
As recently as last week, advocates for remaining in the agreement - including Secretary of State Rex Tillerson, Ivanka Trump and Jared Kushner - seemed to have Trump's ear.
EU lawyers studying the Paris accord, another EU source said, say nothing in the Paris deal prohibits a participant from seeking to reduce its commitments.
That view was upheld by Sue Biniaz, a former State Department legal adviser who left earlier this year and was a key architect behind the Paris agreement.
"Countries might criticise the decision but it wouldn't be a violation of the agreement as a legal matter," she said.
An overwhelming majority of scientists say the burning of fossil fuels like petroleum and coal is a main driver of global climate change, triggering sea level rise, droughts and more frequent violent storms.
(Story corrects to clarify sourcing and wording in first five paragraphs.)
(Additional reporting by Richard Valdmanis; Editing by Tom Heneghan)