WASHINGTON (Reuters) - Democratic presidential hopeful Joe Biden is crafting a climate change policy he hopes will appeal to both environmentalists and the blue-collar voters who elected Donald Trump, according to two sources, carving out a middle ground approach that will likely face heavy resistance from green activists.

FILE PHOTO: U.S. Democratic presidential candidate former Vice President Joe Biden holds a campaign stop in Des Moines, Iowa, U.S. May 1, 2019. REUTERS/Jonathan Ernst /File Photo

The backbone of the policy will likely include the United States re-joining the Paris Climate Agreement and preserving U.S. regulations on emissions and vehicle fuel efficiency that Trump has sought to undo, according to one of the sources, Heather Zichal, who is part of a team advising Biden on climate change. She previously advised President Barack Obama.

The second source, a former energy department official advising Biden’s campaign who asked not to be named, said the policy could also be supportive of nuclear energy and fossil fuel options like natural gas and carbon capture technology, which limit emissions from coal plants and other industrial facilities.

A spokesman for Biden’s campaign, TJ Ducklo, declined to comment on Biden’s emerging climate policy or his advisers, but said Biden takes climate change seriously. “Joe Biden has called climate change an ‘existential threat,’ and as Vice President was instrumental in orchestrating the Paris Climate Accord,” Ducklo said in an emailed statement.

On Twitter, Biden echoed the statement and said he plans to unveil policies that reflect the urgency of climate change.

“I’ll have more specifics on how America can lead on climate in the coming weeks,” he said.

The approach, which has not been previously reported, will set Biden apart from many of his Democratic rivals for the White House who have embraced much tougher climate agendas, like the Green New Deal calling for an end to U.S. fossil fuels use within 10 years. That could make Biden, vice president under Obama, a target of environmental groups and youth activists ahead of next year’s primary elections.

“I respect where they (activist groups) are coming from,” Zichal said. “What we learned from the Obama administration is unless we find middle ground on these issues, we risk not having any policies.”

More than half of the crowded field of Democratic contenders, including Bernie Sanders, Elizabeth Warren, Kamala Harris, Beto O’Rourke, Cory Booker, Jay Inslee and Pete Buttigieg have backed the Green New Deal, and many have also called for a moratorium on drilling on federal land.

Sanders and Inslee on Friday criticized the measured approach that Biden may take.

Inslee praised the Obama-Biden administration for its climate legacy but said “the times and science have changed. We cannot simply go back to the past; we need a bold climate plan for our future.”

On Twitter, Sanders said there is “no middle ground when it comes to climate policy.”

Biden has yet to comment publicly on the Green New Deal, and has said little about climate change in his campaign stops.

Referring to the outlines of Biden’s policy, Varshini Prakash, the director of the Sunrise Movement, which has been pushing candidates to endorse the Green New Deal, said: “We are ready and willing to call out the insufficiency of policies like that.”

Republicans, labor unions, and some Democrats have panned the Green New Deal as unfeasible in a country that has become the world’s top oil and gas producer, and remains a major fossil fuel consumer. The costs of ending the fossil fuel economy and transitioning to clean fuels could soar into the trillions of dollars, and would take decades, they say.

Blocking or reversing the Trump administration’s rollback of over 70 Obama-era climate rules and initiatives, such as the Clean Power Plan, auto efficiency standards, oil and gas methane emissions limits, and the withdrawal from the Paris Climate Agreement could form the foundation of the strategy, she said.

She and the other adviser said Biden’s climate policy was still being formed and the campaign’s approach could change.

OBAMA-ERA EXPERTS

Trump’s successful bid for the White House in 2016 hinged in part on his promise to create blue-collar jobs in oil, mining and manufacturing by rolling back regulations he argued were overly burdensome to business.

In contrast, then-Democratic presidential hopeful Hillary Clinton saw her support dip after she said her aggressive clean energy agenda would “put a lot of coal miners and coal companies out of business,” underscoring the impact environmental policy can have on an election.

Biden’s middle ground approach to environmental policy could put him in a better position than his rivals to take on Trump if it accommodates blue-collar voters. But he must first battle for his party’s nomination by seeking the votes of people who see global warming as a priority.

A recent CNN poll showed that climate change is the top issue for Democratic voters.

Zichal said she is gathering policy advice on Biden’s behalf from experts including former Obama Energy Secretary Ernest Moniz and Frank Verrastro, head of the energy and national security program at the Center for Strategic and International Studies.

Moniz, who declined to comment, co-wrote an op-ed published by CNBC in March with a Bush administration official calling for a “Green Real Deal,” an alternative to the Green New Deal that calls for increased energy efficiency, nuclear energy and carbon capture and storage technology to drive down emissions alongside renewable energy. He has said achieving a zero-carbon target by 2030 is impossible.

Zichal said Biden hopes to be able to use his climate policy to bridge the gap between younger and more progressive Democrats who want bold action on global warming, and the working-class demographic that fear losing jobs as the economy shifts away from fossil fuels.

“He will build a new climate coalition,” she said. “Unions and environmentalists are searching for common ground. We can’t drive a common agenda unless we work together.”