WASHINGTON — A small but growing number of Democrats in Congress want to move ahead with the climate portion of President Biden’s stalled spending bill, saying the urgency of a warming planet demands action and they believe they can muster enough votes to muscle it past Republican opposition.

Faced with the possibility that Democrats could lose control of Congress in November’s midterm elections, the party is now looking to salvage what it can from the $2.2 trillion Build Back Better Act. The sweeping climate-change and social-policy bill passed the House but came to a halt last month when Joe Manchin III, the West Virginia Democrat and swing vote in the Senate, said he opposed it.

However, Mr. Manchin has suggested that he might back various climate provisions in the legislation, leading some Democrats to say the party should regroup around a climate bill.

“The bottom line is that we are running out of time and the only thing that can pass is a package that has the votes,” said Senator Edward Markey, Democrat of Massachusetts and a leading proponent of climate action in Congress.

Mr. Biden endorsed the strategy during a news conference Wednesday, saying that he was “confident we can get pieces, big chunks” of the bill passed.

“I’ve been talking to a number of my colleagues on the Hill,” Mr. Biden told reporters. “I think it’s clear that we would be able to get support for the $500 billion plus for energy and the environment.”

That could mean jettisoning many of the child-care, health care and tax-reform provisions that are priorities for different segments of the Democratic coalition.

But as nearly every part of the United States has recently experienced deadly storms, heat waves, drought and wildfires made worse by climate change, environmentalists say the window is closing for action to curb the pollution that is dangerously heating the planet.

“We don’t have another 10 years to wait,” Mr. Markey said. “We should take what Joe Manchin said, take the climate and clean-energy provisions in the package that have been largely worked through and financed, and take any other provisions in any other part of Build Back Better that have the votes, and put them together as a package.”

Of the social programs that would not make the cut, Mr. Markey said, “that becomes the agenda that we run on in 2022 and 2024.”

Republicans, including those who accept the scientific consensus that climate change is primarily a result of burning fossil fuels, expressed less urgency.

The New York Times asked each of the 50 Senate Republicans if they would support just the climate provisions in the Build Back Better Act if they were presented in a stand-alone bill. None said they would.

“You’d be hard-pressed to find GOP members who would be on board with approving these Democrat priorities,” Senator John Boozman, Republican of Arkansas, said in a statement.

He described the climate provisions as “a far-left agenda" that is “opposed by every Republican in the Senate.”

Two of the 50 Senate Republicans did speak in general terms about how they might back some climate measures. Lindsey Graham of South Carolina said, “Some of it I might be able to support,” while Lisa Murkowski of Alaska said, “I think anything is possible as long as you have an attitude of goodwill and good faith negotiating going here.”

The climate portion of Build Back Better includes about $555 billion aimed at moving the American economy away from its 150-year-old reliance on fossil fuels and toward clean energy sources.

Instead of penalties to punish polluters, the bill offers incentives for industries, utilities and individuals to shift from burning oil, gas and coal for energy and transportation to using wind, solar and other forms of power that do not emit carbon dioxide, the most plentiful of the greenhouse gases that are warming the world.

It would provide about $320 billion in tax credits for producers and buyers of wind, solar and nuclear power. Buyers of electric vehicles would receive up to $12,500 in tax credits. It would extend existing tax credits to lower costs for homeowners of installing solar panels, geothermal pumps and small wind turbines, covering up to 30 percent of the bills.

The bill also includes $6 billion to make buildings more energy efficient and another roughly $6 billion for owners to replace gas-powered furnaces and appliances with electric versions. And it provides billions of dollars for research and development of new technologies to capture carbon dioxide from the air.

Voters across the political spectrum — including conservative Republicans — strongly support tax credits and rebates to consumers, businesses and landlords for energy efficient heating and cooling, solar panels, electric vehicles and other low-emissions or no-carbon technology, according to a September 2021 poll conducted by climate change communications programs at Yale and George Mason universities.

And many of the clean-energy tax credits in Build Back Better have been backed by Republican lawmakers in the past and even written by them. The tax credits, some of which have been law since the 1970s, have typically been extended for just a few years at time. The pending legislation would keep them in place for a decade, lending more certainty to markets, which is designed to spur more investment.

“Lots of the direct benefits of these tax credits already go to red states,” said Barry Rabe, a professor of political science and environmental policy at the University of Michigan. “We have seen major growth of wind and solar production in predominantly Republican states, such as Texas, Oklahoma and North Dakota. And these policies have had bipartisan support over time.”

In saying they would not vote for a stand-alone climate bill, some Republicans touted their own preferred method of curbing emissions. “If you’re serious about climate, put a price on carbon,” said Senator Mitt Romney of Utah. Many lawmakers consider passing a tax on carbon dioxide emissions politically unworkable.

Senator Kevin Cramer of North Dakota said he preferred solutions like support for technologies to capture carbon dioxide from the air and it store it underground. The Build Back Better Act does include billions of dollars for research and development of so-called “carbon capture,” a technology that is not in use at any commercial scale because it is prohibitively expensive.

Mr. Cramer recently joined with former President Trump’s national security adviser, H.R. McMaster, in calling for the United States and Europe to impose a carbon fee on imported goods as part of “a trans-Atlantic climate and trade initiative.”

Senator Chuck Grassley of Iowa, who often refers to himself as the “father” of the wind-energy-production tax credit, said he could support provisions in the bill that bolster wind and solar power but is opposed to sections that would help make electric vehicles more affordable. That would hurt his state’s ethanol industry, he said.

None of the Republicans surveyed said they felt they were facing a planetary emergency.

“I don’t adhere to the alarmism of ‘we’re doomed and we’re doomed soon,’” Mr. Cramer said.

President Biden wants to significantly cut the pollution generated by the United States, the country that has historically pumped the most planet-warming gasses into the atmosphere. He aims to reduce the nation’s greenhouse gas emissions at least 50 percent below 2005 levels by 2030, which is roughly the pace that scientists say the whole world must follow to keep the Earth from warming more than 1.5 degrees Celsius (2.7 degrees Fahrenheit) since the Industrial Revolution. That’s the threshold beyond which scientists say catastrophic events will become more frequent.

Average global temperatures have already increased 1.1 degrees Celsius.

It will be extremely difficult to meet Mr. Biden’s target without the clean energy tax credits in the Build Back Better Act, analysts say.

“This is a make-or-break moment on the climate crisis,” said Jamal Raad, executive director of the climate advocacy group Evergreen Action. “Tough choices need to be made on the other pieces of Build Back Better to get this over the finish line,” he said, adding that he and other environmental groups have communicated this to the White House and Chuck Schumer of New York, the Senate majority leader.

Democratic leaders are reluctant to abandon social programs such as universal prekindergarten or lower costs for prescription drugs because they provide benefits that are immediately felt by American families and would demonstrate to voters that the party can deliver on its promises.

“Some of these other pieces — the health care and prescription-drug proposals — are the most popular part of the package with voters,” said Celinda Lake, a Democratic strategist and pollster.

Even though Democrats control the White House and Congress, the party is stymied in the Senate by procedural rules, unified Republican opposition and the fact that the chamber is split 50-50 with Democrats and their two independent allies able to prevail only because of the tiebreaking authority of Vice President Kamala Harris.

If Democrats were to try to bring a climate bill to the Senate floor for a vote, they would need to be joined by at least 10 Republicans to clear a 60-vote threshold to push past a Republican filibuster.

They can bypass a filibuster by using a fast-track procedure known as reconciliation, which would allow them to bring the legislation to the Senate floor with a simple 51-vote majority. That’s the route that Senate leaders have been trying to use to advance the broader Build Back Better bill.

But under the Senate rules, the reconciliation process can only be used once each fiscal year. That’s why Democratic leaders are still trying to use their one opportunity to pack as much of Mr. Biden’s agenda as possible into a single piece of legislation. “They have one bite at the apple,” said Kevin Book, an analyst with ClearView Energy, a nonpartisan policy analysis firm.

Asked why Republicans would block a procedural move to allow a vote on a climate bill, a spokesman for Mitch McConnell, the Senate Republican leader, pointed to remarks the senator made in November about the climate section of the Build Back Better package. He called it “a reckless taxing and spending spree that would hammer American families and the affordable energy they need to power and heat their homes and drive their cars.”

Mr. Rabe said that policy appears to be a casualty of Republican efforts to deny Mr. Biden a major legislative win in an election year. “Even those policies that might scream out for opportunity for bipartisanship run into this partisanship,” he said.

Emily Cochrane contributed reporting.