Representative Mike Johnson of Louisiana, the newly elected House speaker, has questioned climate science, opposed clean energy and received more campaign contributions from oil and gas companies than from any other industry last year.

Even as other Republican lawmakers increasingly accept the overwhelming scientific consensus that human activity is dangerously heating the planet, the unanimous election of Mr. Johnson on Wednesday suggests that his views may not be out of step with the rest of his party.

Indeed, surveys show that climate science has been politicized in the United States to an extent not experienced in most other countries. A Pew Research Center survey released Tuesday found that a vast majority of Democrats polled — 85 percent — said that climate change is an extremely or very serious problem, while 47 percent of Republicans viewed climate change as not too serious or not a problem at all.

“It should concern us all that someone with such extreme views and so beholden to the fossil fuel industry has such power and influence during a time when bold action is more critical than ever,” said Ben Jealous, the executive director of the Sierra Club, an environment group.

Mr. Johnson, whose district includes Shreveport, a former oil town that has diversified over the past decade, was first elected to Congress in 2016. A former constitutional lawyer, he does not sit on committees that decide the fate of major energy issues.

But he has consistently voted against dozens of climate bills and amendments, opposing legislation that would require companies to disclose their risks from climate change and bills that would reduce leaks of methane, a potent greenhouse gas, from oil and gas wells. He has voted for measures that would cut funding to the Environmental Protection Agency.

At a town hall in 2017, Mr. Johnson said: “The climate is changing, but the question is, is it being caused by natural cycles over the span of the Earth’s history? Or is it changing because we drive S.U.V.s? I don’t believe in the latter. I don’t think that’s the primary driver.”

After Representative Alexandria Ocasio Cortez, Democrat of New York, and Senator Ed Markey, Democrat of Massachusetts, unsuccessfully filed “Green New Deal” legislation in 2019 to aggressively cut emissions, move the country toward 100 percent renewable energy and address a host of social issues, Mr. Johnson hit back.

Then the chairman of the Republican Study Committee, Mr. Johnson issued a 13-page paper dubbing the climate plan “A Greedy New Steal.” He called the Democrats’ plan “a thinly veiled attempt to implement the policies that would usher in a new socialist society in America.”

Last year, when Democrats passed climate legislation that provided for investing $370 billion in clean energy, Mr. Johnson criticized it as a plan to send taxpayer dollars to “green energy slush funds.” Much of the private investment stemming from that law is taking hold in Republican-led states.

Since 2018, Mr. Johnson has received about $240,000 in campaign contributions from the oil and gas industry, according to Open Secrets, a campaign finance watchdog.

The League of Conservation Voters, an environmental group, has given Mr. Johnson a lifetime score of 2 percent. The American Energy Alliance, which represents fossil fuel interests, gave him a score of 100 percent in 2022.

The scores, however, are nearly identical to those earned by Mr. Johnson’s predecessor as speaker, Representative Kevin McCarthy of California, who did acknowledge climate science.

But Mr. McCarthy “made sure that the MAGA House Republicans acted at Big Oil’s behest day in and day out, and it’s clear that Johnson will be just as extreme if not worse,” said Tiernan Sittenfeld, the senior vice president of government affairs for the League of Conservation Voters.

This year is shaping up to be the hottest year on record. The United States has experienced 23 billion-dollar disasters resulting from extreme weather linked to climate change in 2023, a record for this point in the year, according to the National Oceanic and Atmospheric Administration.

Heather Reams, president of Citizens for Responsible Energy Solutions, a group that works with Republicans on clean energy, said she expected that Mr. Johnson would try to repeal the climate law, known as the Inflation Reduction Act.

But, she said, “The more embedded these tax incentives become, particularly in the red districts, I think it will be hard to repeal.”

Representative John Curtis of Utah, a Republican who leads a conservative climate change caucus, has spoken with Mr. Johnson about the issue, Mr. Curtis’s spokesman Adam Cloch said.

“We look forward to working with him on our priorities,” Mr. Cloch said. “Conservatives are at the climate table.”

The Independent Petroleum Association of America applauded Mr. Johnson’s election, saying that as a Louisiana representative, he “knows the importance of both Haynesville shale and Gulf of Mexico production to America’s energy future.” Steven J. Milloy, a prominent climate denialist, called Mr. Johnson “a quantum leap improvement” over Mr. McCarthy.