“All of them need to demonstrate a level of independence from the national party in order to survive,” said Nathan Gonzales, editor of the nonpartisan Rothenberg & Gonzales Political Report, speaking of the five lawmakers backed by Mr. Faison’s group. “They’ll need to declare independence from Donald Trump.”

In 2015, Ms. Ayotte broke with her party to vote against a measure written by Mr. McConnell that would have blocked Mr. Obama’s climate change rules. She also voted for a program to establish grants to schools for climate change education, against a proposal to block the Obama administration from signing on to the Paris climate change accord, and in favor of a federal fund to respond to the threat of climate change.

Mr. Portman voted with his party on most of those measures, but also voted in favor of the fund to respond to climate threats. He has worked for years with Senator Jeanne Shaheen, Democrat of New Hampshire, on a bill to improve energy efficiency in buildings. He is a former board member of the Nature Conservancy and is a co-author of legislation to support cleanup of the Great Lakes.

The three House members backed by Mr. Faison’s group are among just 13 Republicans who have signed on to a resolution, offered by Representative Chris Gibson, Republican of New York. “The resolution was a vehicle to find out which Republicans were willing to step up and take some action,” said Steve Valk, a spokesman for Citizen’s Climate Lobby.



But while those five Republicans’ environmental records stand out from many in their party, they have voted more times against environmental regulations than in favor. The League of Conservation Voters, which tracks lawmakers’ environmental records on a scale of 1 to 100, have given lifetime scores to Ms. Ayotte of 35 percent, Mr. Portman of 20 percent, Mr. Curbelo of 23 percent, Mr. Reed of 6 percent and Ms. Stefanik of 9 percent. “To give House Republicans like Elise Stefanik, Tom Reed or Carlos Curbelo credit for acknowledging that climate change is real is a very low bar,” said Meredith Kelly, a spokeswoman for the Democratic Congressional Campaign Committee.

In Miami, Mr. Curbelo’s opponent, Annette Tadeo, a Democrat, has slammed his climate positions as hypocritical. “Big oil and gas lobbyists have been filling his campaign coffers with thousands of dollars in cash, in exchange for his advocacy for offshore drilling,” she said in a statement.

In Ohio, Mr. Portman is fighting to keep his seat against a former governor, Ted Strickland, who notes his support of Mr. Obama’s climate plan and slams Mr. Portman for voting against it.