WASHINGTON — A year after he entered the White House with a vow that fighting global warming would be a driving priority for his administration, President Biden’s climate agenda is mired in delay and facing legal, legislative and political headwinds that could diminish or dismantle it entirely.

His two main avenues for significant climate action are legislation and regulation. But even Mr. Biden’s top aides and closest allies now concede that the legislative centerpiece of his climate plan is unlikely to become law in the face of steadfast Republican opposition. And regulations that are now under development — strict limits on the pollution from cars and power plants that is dangerously heating the planet — could be curtailed or blocked by the conservative majority on the Supreme Court.

With gasoline prices surging after the Russian invasion of Ukraine and images receding of last summer’s climate disasters — wildfires that raged through seven states, heat waves and floods — Republicans and oil companies are newly emboldened in calling for more drilling and less emphasis on climate change.

“The U.S. oil companies are like a prisoner that was condemned to death, and suddenly the warden of the prison lets them out and wants them to produce as much oil as quickly as possible,” said Robert McNally, a consultant who was a senior energy and economic adviser to President George W. Bush. “Now, the president is saying to them, help me out of a jam. It’s a panicked response to high oil prices.”

On Thursday, President Biden said he would release one million barrels of oil a day from the Strategic Petroleum Reserve for as long as 180 days to help bring down global oil prices. The scale and duration of such a release would be historic. The United States also plans to increase exports of natural gas to help Europe wean itself from Russian supplies. Environmentalists are concerned that both of those moves will lead to more domestic drilling at a moment when scientists say nations must sharply and quickly cut fossil fuel use.

The president used the announcement about the petroleum reserve to make a plea for his stymied climate legislation, saying that he was boosting gas and oil supplies to deal with an immediate crisis but that the country’s long term energy independence should be rooted in wind, solar and other renewable sources that are insulated from global market fluctuations.

“Ultimately, we and the whole world need to reduce our dependence on fossil fuels altogether,” Mr. Biden said. “We need to choose long-term security over energy and climate vulnerability. We need to double down on our commitment to clean energy and tackling the climate crisis with our partners and allies around the world. And we can do that by passing my plan that’s literally before the Senate right now, the United States Congress right now.”

Still, the administration has advanced some climate policies, certainly more than Mr. Biden’s predecessor, who mocked climate change. The Securities and Exchange Commission proposed a landmark rule requiring companies to disclose their financial risk from climate change. The Biden administration approved the nation’s first major offshore wind farm and is moving forward with plans to develop wind farms along much of the United States coastline.

In addition, the Environmental Protection Agency is advancing new rules to limit methane, a potent greenhouse gas that leaks from oil and gas wells. The administration is setting tougher energy efficiency standards for refrigerators, washers, dryers and other appliances. And through the bipartisan infrastructure law, it is providing $3.2 billion to weatherize homes and $5 billion to help states create networks of electric vehicle charging stations.

But Mr. Biden’s strategy to seed climate policy across the federal government has suffered setbacks. His nomination of Sarah Bloom Raskin for vice chairman of the Federal Reserve was scuttled by Senator Joe Manchin III, Democrat of West Virginia, who objected to her views that climate change poses a serious risk to the financial system. Senator Manchin and Republicans also pressured the Federal Energy Regulatory Commission to back off plans to consider climate effects when approving new gas pipelines.

Republicans have shown little interest in addressing climate change, despite the overwhelming consensus of the scientific community that nations must take immediate action to slash emissions from fossil fuels or face a harrowing future of drought, floods, fires, displacement, famine and more. The planet is warming so quickly, it is outpacing humanity’s ability to adapt, according to the most recent report for the United Nations written by 270 researchers from 67 countries.

But the majority of Republicans in Congress have been silent when it comes to the science and have sought to portray the Democrats as “climate elites” who are out of touch with most Americans.

Senator John Barrasso of Wyoming, the ranking Republican on the Senate Energy and Natural Resources committee, attacked Mr. Biden’s proposed 2023 budget as “climate extremism” because he is seeking $45 billion for governmentwide efforts to reduce pollution, expand conservation, research clean energy technologies and prepare for and respond to extreme weather events.

“President Biden wants to spend more taxpayer dollars on his green energy schemes instead of increasing American energy production to solve the energy crisis he created,” Senator Barrasso said on Monday. Wyoming is the nation’s top coal producing state, is eighth in terms of crude oil production and ninth when it comes to crude oil.

With an eye toward this fall’s midterm elections, Republicans have ramped up attacks on Mr. Biden’s climate agenda. The Republican National Committee has launched a campaign to register voters at gas stations across the country, aiming to connect high prices at the pump to Mr. Biden’s policies.

“It’s kind of a perfect storm,” wrote David Axelrod, a Democratic political strategist and former top counselor to President Barack Obama, in an email. “The economic dislocations caused by the pandemic and war in Ukraine have led to record gas prices, and with them, tremendous pressure to encourage more oil and gas production. All in an election year.”

Experts say that it is now impossible for Mr. Biden to meet his pledge to the world that the United States will cut its emissions in half by 2030, the amount the scientists say is necessary if the planet’s largest economy is to do its part to avoid the most catastrophic consequences of global warming.

“Fifty percent by 2030 was always a stretch goal,” said David G. Victor, an expert in climate policy at the University of California, San Diego. “I never thought it was achievable. Certainly that’s not going to happen now.”

Mr. Biden’s best hope for climate action is in the $2.2 trillion climate and social spending legislation stalled on Capitol Hill, which includes about $300 billion in tax incentives designed to galvanize markets for wind and solar energy and electric vehicles. If enacted, it could cut the nation’s emissions roughly 25 percent by 2030, getting about halfway to Mr. Biden’s promised target.

The House passed the legislation last year but it came to a standstill in the Senate in December, when Senator Manchin said he would not vote for it. Senator Manchin’s vote is essential for passage of the bill in the evenly divided Senate, where no Republicans are expected to vote for the measure.

In recent days, Senator Manchin has suggested that he is open to discussing a scaled-down version of the bill, including some of the clean energy tax credits. He said in an interview last week that “there is no formal negotiation” happening over text of a bill. “Just a lot of chatter back and forth.”

But Senator Manchin’s idea of a climate package would also include provisions to expand domestic oil and gas drilling — a step that climate experts say could undermine the emission reductions goals of the bill. Senator Manchin, who has financial ties to the coal industry, is the top recipient in the Senate of campaign contributions from the fossil fuel industry.

Even if Senator Manchin returns to table to negotiate new legislation, some Democrats remain skeptical that it could get over the finish line.

“If you ask me to handicap it, it’s probably less than 50-50,” said John Podesta, a Democratic strategist and former top climate adviser to Mr. Obama, of the probability that some portion of the climate legislation could be enacted this year, although he added, “But it’s not zero!”

Gina McCarthy, Mr. Biden’s top climate adviser, agreed with Mr. Podesta. “Wasn’t that always the case?” she said in an interview last Thursday. But she said that Mr. Biden would persevere in efforts to pass a bill by this fall.

Timing is critical: If the legislation does not pass by the end of the year, it will almost certainly die, since Republicans are favored to win control of at least the House in November.

Chuck Schumer, the Senate majority leader, said he was still trying to make a deal. “Confronting climate change is extremely important,” he said. “I’m doing everything I can to get the strongest climate change legislation that has the full support of the Democratic caucus.” Senator Schumer has continued informal talks with Senator Manchin, dining with him at an Italian restaurant on Capitol Hill in February, according to a person familiar with their conversations.

But lawmakers would need to get working “very quickly” to move a new version of the legislation, said Bobby Andres, a senior policy adviser to the Senate Finance Committee, which has jurisdiction over the clean energy tax provisions. “We still don’t have a new agreement to move forward,” he said, adding, “Congress could certainly fail to get this done. Failure is, unfortunately, a possibility.”

Meanwhile, White House aides are worried that regulations to force polluting industries to cut emissions could be severely limited by the Supreme Court. The Environmental Protection Agency is drafting two regulations to reduce emissions from vehicle tailpipes and power plant smokestacks. If those rules are stringent and enacted soon, analysts say, they could cut the nation’s greenhouse pollution and accelerate its transition to electric vehicles and wind and solar power.

But the E.P.A. is awaiting a Supreme Court decision in West Virginia v. Environmental Protection Agency, a legal challenge brought by 18 Republican attorneys general. Backed by some of the nation’s largest coal companies, the attorneys general want the justices to sharply limit, if not eliminate, the agency’s authority to regulate greenhouse gas pollution from power plants.

After February’s oral arguments, legal experts said they believed that the majority of the justices, six of whom were appointed by Republican presidents, including three Trump appointees, would be sympathetic to the plaintiffs. “This is a serious threat to regulations,” said Richard Revesz, who teaches environmental law at New York University and filed a legal brief in the case in support of the administration.

The agency could still make an impact with another rule, which is not expected to be completed until 2023, designed to force auto companies to rapidly increase sales of zero-emission electric vehicles.

Mr. Biden’s allies remain hopeful. Senator Ed Markey, Democrat of Massachusetts, said that the president had approached him at a Democratic retreat in Philadelphia a few weeks ago to quietly assure him that climate remained a priority. “He made it very clear to me that he is still committed to having a strong climate package become law this year,” Senator Markey said.

Mr. Podesta said that if that’s true, the president needs to keep talking about it: “At the end of the day he’s going to have to make the case to the American people.”

Lisa Friedman contributed reporting.