Climate change is starting to become a political worry for some Republicans.

The big picture: For years, Republicans could ignore the issue or outright question mainstream climate science without political worry. That’s starting to change. Some congressional Republicans are beginning to find it in their political interest to at least acknowledge climate change and oppose efforts to weaken existing policies.

The subtle but significant shift is fueled by disparate factors, including a stronger economy and President Trump’s dismissive policies on climate.

“Moderate Republicans running this cycle are going to look for places to distance themselves in some places and appeal somehow to the middle, and [climate] is a fairly safe issue to do so.”

— Adrian Gray, Republican pollster

Unlike the backlash Republicans face for disagreeing with Trump on many issues, Gray says his polling shows that most Republican voters don’t penalize their lawmakers for acknowledging climate change is real and a problem, even though Trump openly mocks it.

This distinction comes despite the fact polling shows climate change remains a low priority for most voters, said Gray, who has done work for environmental groups.

Republican Rep. Carlos Curbelo embodies the moderate GOP mold considered key to Republicans keeping control of the House. He represents the tip of Florida, a swing district whose residents regularly experience rising sea levels, one of the clearest and most present impacts of climate change.

Climate change is a top priority for Curbelo, who has regularly criticized Trump on several issues.

He’s introducing legislation today that taxes carbon emissions, with at least one fellow Republican, Curbelo said.

He’s a co-founder of a bipartisan House caucus that acknowledges climate change.

The other side(s): Curbelo’s Democratic challenger, Debbie Mucarsel-Powell, is accusing the congressman of being ineffective and disingenuous with his work addressing climate change. Meanwhile, Americans for Tax Reform, a conservative group influential with Republicans, is holding an event today highlighting its opposition to what it’s calling the “giant job-crushing carbon tax” bill Curbelo is introducing.

Those cross-pressures highlight the political danger Curbelo faces in the midterm elections. His district is a top target for the Democratic Congressional Campaign Committee, and voters there overwhelmingly supported Hillary Clinton in the 2016 presidential contest.

The 38-year-old Curbelo, first elected to Congress in 2014, is unusually nonchalant about this criticism and the potential for it to ultimately boot him from Washington.

“I don’t worry about those kinds of things. I didn’t go to college to serve in Congress. I’m going to be as effective as possible while I’m here. The day I’m not here, I’ll be perfectly fine.”

— Curbelo

The bipartisan Climate Solutions Caucus Curbelo helped found two years ago with fellow Florida Rep. Ted Deutch, a Democrat, faces accusations from some environmentalists that it’s mostly an empty effort giving political cover to Republicans. Its record does show its limits:

The caucus hasn’t put forth any substantive policies.

Most GOP members of the caucus supported a non-binding but symbolically important resolution last week opposing a carbon tax.

But the fact that some Republicans see a need to join an effort acknowledging climate change represents a political turning point, considering that the party as a whole has dismissed or denied outright mainstream climate science for most of the past decade. Of the 42 Republican members of the caucus, 35 have joined since Trump’s election.

Leading up to last week’s vote on the anti-carbon tax resolution, some Republicans felt “angst” about it, according to a senior GOP aide who spoke on the condition of anonymity to be candid about inner party workings.

After the vote, the aide expressed surprise at the number of Republicans who opposed the resolution: six, including five who are running for reelection. While objectively small, it’s still a notable change from the unanimous GOP backing in a near identical vote two years ago.

Increasingly, Republicans are voting against opposing moves on climate policy — a political double negative. Last July, dozens of House Republicans voted to defeat an amendment that would have blocked a Defense Department study of climate change.

This political shift is by no means universal, and it isn't leading to broad support for policies. It's one thing to acknowledge climate change is real, but it's another, big step to put forward policies, and so far Curbelo is an outlier.

GOP Reps. Steve Scalise of Louisiana and David McKinley of West Virginia sponsored last week’s anti-carbon tax resolution for compelling reasons: they represent fossil-fuel constituents who would get hit hardest by a tax on carbon emitted from oil, natural gas and coal.

Sen. Joe Manchin, a Democrat from West Virginia running for reelection this year, told me last week he would still support today an advertisement he ran in 2010 shooting climate-change legislation with a gun.

One former congressional Republican who got voted out largely for his vote in support of that bill — Bob Inglis of South Carolina — says times are changing, albeit slowly.

“That was the darkest days of the recession, the reddest district in the reddest state in the nation," Inglis said. "So things are turning, but they haven’t turned completely yet.”