The Environmental Protection Agency on Monday announced strengthened limits on pollution from automobile tailpipes in a bid to reduce a major source of the carbon dioxide emissions that are heating the planet.

The more stringent rule — the most significant climate action taken to date by the Biden administration and highest level ever set for fuel economy — would require passenger vehicles to travel an average of 55 miles per gallon of gasoline by 2026, from just under 38 miles per gallon today.

That would prevent the release of 3.1 billion tons of climate-warming carbon dioxide through 2050, according to the E.P.A. It would save about 360 billion gallons of gasoline from being burned, leading to a 15 percent annual reduction in the nation’s gasoline consumption by 2050. And motorists would save about $1,080 in fuel costs over the lifetime of more efficient vehicles, the agency estimated.

The Biden administration is expected to lean heavily on executive action and regulations like the new tailpipe rule after the centerpiece of the president’s climate agenda, far-reaching legislation that would have transformed the energy and transportation sectors, was essentially scuttled on Sunday by Senator Joe Manchin III, the West Virginia Democrat who holds the swing vote in an evenly split Senate.

The tailpipe rule, which will take effect 60 days after it is published in the Federal Register and apply to model years 2023 to 2026, is a return of sorts to regulations enacted by the Obama administration in 2012, which required that passenger vehicles sold by automakers achieve an average of roughly 51 miles per gallon by 2025. President Donald J. Trump weakened the standard in 2020 to about 44 miles per gallon by 2026.

“We followed the science, we listened to stakeholders, and we are setting robust and rigorous standards that will aggressively reduce the pollution that is harming people and our planet — and save families money at the same time,” Michael S. Regan, the administrator of the E.P.A., said in a statement.

Transportation is the largest single source of greenhouse gases generated by the United States, representing 29 percent of the nation’s total emissions.

A recent report by the International Energy Agency found that nations would have to end the sale of new gasoline-powered cars by 2035 to keep average global temperatures from increasing 1.5 Celsius, compared with levels during the Industrial Revolution. That’s the threshold beyond which scientists say the Earth faces irreversible damage. The planet has already warmed an average of about 1.1 degrees Celsius since the late 1800s.

Climate experts said the new tailpipe rule is a first step in Mr. Biden’s push to rapidly shift American drivers from cars and trucks powered by the internal combustion engines of the last century to zero-emission electric vehicles.

The new Biden rule “is basically just recapturing the emissions cuts that we lost during the Trump rollback,” said Jeff Alson, a former E.P.A. senior engineer and policy adviser who worked on the Obama auto emissions standards. “That’s good, but it’s not going to get us anywhere near the level we’ve got to get to reduce vehicle emissions enough to protect the planet.”

About $26 billion in tax incentives to speed up the adoption of electric vehicles has been stuck in limbo on Capitol Hill, part of a larger $2.2 trillion bill, known as the Build Back Better Act that faces opposition from Mr. Manchin. Among the bill’s provisions are a tax credit of $7,500 for purchasers of electric vehicles, plus an additional incentive of $4,500 if the vehicles are assembled by union workers.

Mr. Biden has set a goal for electric vehicles to make up 50 percent of all new car sales by 2030 in order to slash planet-heating emissions and slow climate change. But electric cars are on track to total just 4 percent of American sales in 2021, a hint of the scale of the challenge Mr. Biden faces.

A significant step was taken last month, when Congress passed a $1 trillion infrastructure bill that included $7.5 billion to build about 500,000 electric charging stations nationwide, plus another $7.5 billion to help bolster supply chains needed to produce electric vehicles. This month, Mr. Biden signed an executive order requiring the federal government to purchase only zero-emission cars and trucks by 2035.

But more is needed to reach Mr. Biden’s goal, climate advocates say.

“The short-term rule that the president is announcing now isn’t up to the challenge that he himself named, that global warming is an existential threat,” said Dan Becker, director of the Safe Climate Transport Campaign at the Center for Biological Diversity. “What we really need is an aggressive rule as soon as possible to phase out the gasoline-powered vehicles that are guzzling and polluting and replace them with EVs that have no tailpipe.”

So E.P.A. officials are working on a future regulation for vehicles built in model year 2027 and beyond that would compel automakers to ramp up sales of electric vehicles. They say they hope to publish a draft in 2022 and to complete it before the end of Mr. Biden’s term.