Protesters calling for massive economic and political changes to curb the effects of global warming hold a sit in around the Wall Street Bull statue on Broadway on September 22, 2014 in New York City. Andrew Burton/Getty NEW YORK (Reuters) - President Donald Trump's outspoken doubts about climate change and his administration's efforts to roll back regulation to combat it have stirred a sleepy faction in U.S. politics: the Republican environmental movement.

The various groups represent conservatives, Catholics and the younger generation of Republicans who, unlike Trump, not only recognize the science of climate change but want to see their party wrest the initiative from Democrats and lead efforts to combat global warming.

Conservative green groups such as ConservAmerica and republicEn, along with politically neutral religious groups such as Catholic Climate Covenant and bipartisan groups such as the Citizens Climate Lobby, have ramped up efforts to recruit more congressional Republicans to work on addressing climate change since Trump's election.

Conservative environmental advocates promote what they call "free enterprise" solutions to climate change, like a carbon tax. That stands in contrast to the approach of liberal environmentalists under former President Barack Obama, who backed bans on certain kinds of oil drilling and regulations aimed at discouraging petroleum use.

But whatever their differences, the conservative groups say they have an important role to play.

"Conservatives now have a chance to earn back the trust of Americans on environmental issues," said Alex Bozmoski, director of strategy for republicEn. "They can lead in a completely different direction that actually grows the economy while cutting greenhouse gasses."

The activists' efforts have not swayed anywhere near a majority yet on Capitol Hill. Only 20 or so of the 237 Republicans in the U.S. House of Representatives have spoken out on climate change this year. But they hope to build a big enough bloc in Congress, or enough influence at the White House, to temper Trump's agenda.

Lobbying has yielded some early results: a pro-environment voting bloc in Congress, the Climate Solutions Caucus, for example, has signed on more Republicans in the last two months than in it had in the final year of Obama's administration — its first year in existence.

Urged on by a coalition of conservative and religious groups, including the Catholic Climate Covenant, a handful of additional Republicans have also signed a congressional resolution pledging to address climate change.

The resolution was non-binding, but it represented a direct challenge to Trump's climate stance, a high-profile signal of dissent within his party.

"It's like Alcoholics Anonymous — you've got to first recognize you've got a problem before you can deal with it," said Mark Sanford, a Republican Congressman from South Carolina who signed the resolution.

Melinda Pierce, legislative director for the more than 100-year-old Sierra Club environmental group, said she was happy to see "enlightened Republicans" beginning to act on climate change. But Pierce added, "Legislative action is a long time away based on, at least, the Republican leadership."

Pierce also said she was skeptical of free enterprise solutions advocated by conservative environmental groups like republicEn, which she said sounded to her like "we have to pay them not to pollute."

Jose Aguto, associate director of the Catholic Climate Covenant, said Republicans are the only major political party in the world not convinced by climate change.

"Once they accept the reality and science of climate change, we will have reached a tipping point in the political will for solutions.”

Trump hoax

Delegates from West Virginia hold signs supporting coal on the second day of the Republican National Convention in Cleveland, Ohio, U.S. July 19, 2016. Aaron P. Bernstein/Reuters

Trump has raised the hackles of many environmentalists since taking office. He has overturned several Obama-era environmental regulations, and last week he proposed slashing the Environmental Protection Agency budget by 31 percent.

During his presidential campaign Trump called climate change a "hoax" and vowed to pull the United States out of the Paris accord, a global pact to fight it – tapping into a well of Republican concern that the United States' energy habits would be policed by the United Nations.

But Republican bias against climate science is out of step with the majority of Americans. A Reuters/Ipsos poll shows a majority of Republican supporters agree the United States should play a leading role in combating climate change.

"It shouldn't surprise anyone that more and more Republicans are interested in this issue," said Republican Representative Carlos Curbelo of Florida. "This issue was regrettably politicized some 20 or so years ago, and we are in the process of taking some of the politics out."

A possible climate change adviser

Republican presidential candidate Donald Trump speaks during a campaign stop, Tuesday, June 28, 2016, at Alumisource, a metals recycling facility in Monessen, Pa. Keith Srakocic/AP On Feb. 8, representatives from a newly formed group of Republican statesmen, the Climate Leadership Council, including former Treasury secretaries Henry Paulson and James A. Baker, met with senior administration officials to push a carbon tax.

"We got a very respectful hearing," said the council's CEO, Ted Halstead. "We've also been meeting with Republicans on the Hill and have found open minds."

The White House did not comment on the meetings.

Billionaire Republican donor and environmental advocate Andy Sabin, meanwhile, said he has been speaking directly with White House officials in hope of becoming Trump's unpaid climate change adviser – modeled on the role of fellow billionaire Carl Icahn in advising Trump on regulation.

Focusing on health concerns would be the most effective way to get Trump to try to slow climate change, said Sabin, a precious metals magnate.

When asked about the chances of Sabin getting the position, a White House spokeswoman said, "We don't have an announcement at this time."

'Sno balled'

Sen. James Inhofe Screengrab Republican Senator James Inhofe incurred public ridicule two years ago after marching into the Capitol Building with a snowball, claiming the cold weather disproved Obama's climate change claims.

This year, republicEn used the incident as part of a humorous rallying call on Valentine's Day. Volunteers delivered greeting cards to lawmakers quoting Secretary of State Rex Tillerson, in his former role as chief executive officer of Exxon, declaring climate change to be a serious risk warranting "thoughtful action."

Along with the card were coconut-coated cakes called Sno Balls, a photograph of Inhofe and a poem:

"Roses are red, snowballs are white, together we'll get the solution right."

(Editing by Richard Valdmanis, Simon Webb and Leslie Adler)