President Trump and former vice president Joe Biden laid out starkly different visions Thursday night on whether the United States needs to transition away from fossil fuels to address climate change, in the lengthiest exchange two presidential candidates have ever had on the topic.

In the nearly 12-minute discussion, the Democratic standard-bearer pledged to move the United States away from oil in favor of renewable energy and predicted the strategy would generate millions of jobs. The president, in contrast, said Biden’s plan would be costly and hurt the economy, particularly in oil-producing states where the two men are competing for votes.

Biden said climate change posed “an existential threat to humanity” and that in eight to 10 years, the country would “pass the point of no return.”

“We have a moral obligation to deal with it,” he said.

Moments later, Trump asked Biden, “Would you close down the oil industry?”

“Yes. I would transition,” Biden said. “Because the oil industry pollutes, significantly. … Because it has to be replaced by renewable energy.”

Biden said the transition would occur “over time, over time. And I’d stop giving to the oil industry. I’d stop giving them federal subsidies.”

Trump seized on those comments. “Basically, what he is saying is he’s going to destroy the oil industry,” the president said. “Will you remember that, Texas? Will you remember that, Pennsylvania, Oklahoma?”

Later, at the airport, Biden tried to clarify his comments, saying that he wants to end federal subsidies to oil companies. “We’re not going to get rid of fossil fuels,” Biden said. “We’re going to get rid of subsidies for fossil fuels.”

Scientists say nations have only about 10 years to cut emissions of greenhouse gases — mostly produced by burning fossil fuels — to avoid irreversible, catastrophic damage to the planet.

On stage, Trump touted the fact that he withdrew from the landmark 2015 Paris climate agreement, which aims to keep the globe from warming more than 1.5 degrees Celsius (2.7 degrees Fahrenheit) by the end of the century. That’s the point beyond which scientists say the planet will be irreversibly damaged.

“We were going to have to spend trillions of dollars,” Trump said, adding: “I will not sacrifice tens of millions of jobs, thousands of companies.”

Biden said he would have the United States rejoin the Paris accord and that fighting climate change would “create millions of new good-paying jobs.”

While Trump claimed Biden’s plan would cost $100 trillion, Biden has estimated the cost at about $2 trillion over four years. He said Thursday night that it would cover the costs of 50,000 recharging stations for electric vehicles, improvements in millions of buildings’ energy efficiency and other infrastructure.

When asked about the fact that Americans of color are disproportionately exposed to pollution because they live near oil refineries and other energy operations, Trump said the health risks they face pale in comparison to the wage growth they’d seen from those polluting industries during his first three years in office.

“They’re making a tremendous amount of money,” the president said, adding that his administration “saved” the oil industry from collapse. “Now it’s very vibrant again and everybody has very inexpensive gasoline.”

Recalling his own childhood in Delaware growing up near oil and gas refineries, Biden argued that the government needed to do more to curb pollution from fossil fuels. “The fact is, those front-line communities, it doesn’t matter what you’re paying them, it’s how you keep them safe,” he said.

Trump falsely said Biden supports a ban on fracking — a claim his Democratic opponent has repeatedly knocked down.

“I never said I oppose fracking,” Biden said. Instead, Biden has said he wants to end permitting for fracking and other oil and gas drilling only on federal lands in the West — not on state or private lands such as those in Pennsylvania, a crucial swing state that both candidates are heavily courting.

And while Trump claimed, “We are energy independent,” the United States continues to import a significant amount of foreign oil. He derided Biden’s plans to improve energy efficiency, saying, “They want to knock down buildings and build new buildings with little, tiny windows.”

Climate change had virtually disappeared from presidential debates for two decades until last month, when there was simply no avoiding it, in a year marked by record wildfires, devastating hurricanes and other climate-related catastrophes such as drought and floods.

“Today, climate disasters are up close and personal for Americans,” said Jeremy Symons, a consultant to environmental nonprofit groups and former vice president for political affairs at the Environmental Defense Fund, who has closely followed U.S. climate policy for decades. “It’s leaped out of the science books and into the communities where people have to deal with the deadly consequences of pretending it doesn’t exist.”

In a stark reminder of how climate change is already transforming Americans’ lives, a Colorado wildfire expanded by 140,000 acres in a day, at an elevation of 9,000 feet, where snow would usually be falling this time of year. The East Troublesome Fire is burning largely in Grand County and has reached Rocky Mountain National Park. It has made it through dry, brittle trees ravaged by a bark beetle infestation and has prompted the evacuation of hundreds of Coloradans.

The blaze now ranks as the state’s second-largest on record. Three of Colorado’s five largest wildfires in history have occurred this year. The incident commander said Thursday that East Troublesome Fire’s rate of expansion is “unheard of.”

The Trump-Biden debate tracked much the same ground as the last time there was a substantive discussion about climate in a presidential debate — the 2000 match between Democrat Al Gore and Republican George W. Bush.

“I think that in this 21st century, we will soon see the consequences of what is called ‘global warming,’” Gore said that evening. “The world’s temperature is going up, weather patterns are changing, storms are getting more violent and unpredictable.”

Bush agreed the problem deserved attention, though he didn’t feel a similar urgency. “Global warming needs to be taken very seriously, and I take it seriously,” he said. “But science — there’s differing opinions. And before we react, I think it’s best to have the full accounting, full understanding of what’s taking place.”

“It’s a sea change to have this kind of attention on climate change,” Symons said.

The shift comes as Americans increasingly express concern about the warming planet. A poll last year by The Washington Post and the Kaiser Family Foundation found that a growing number of Americans describe climate change as a crisis, and two-thirds said Trump is doing too little to tackle the problem. It also found that a strong majority of Americans — about 8 in 10 — say that human activity is fueling climate change, and roughly half believe action is urgently needed within the next decade if humanity is to avert its worst effects.

In addition, even as the coronavirus pandemic had dwarfed most other concerns, climate change emerged as a front-burner issue during the Democratic presidential primaries, in ways difficult to fathom only a few years ago. Voters in numerous states ranked it as one of their top concerns, alongside health care and economic issues.

Then there are the real-world effects that continue to mount: Record wildfires in California and throughout much of the West. A historic hurricane season in the Atlantic. Raging fires in Siberia. Massive amounts of ice melting across the Arctic. Rising seas that affect coastal communities around the nation. Both droughts and floods in the Midwest.

It is difficult to imagine that climate change will fade again anytime soon as an issue in presidential contests, Symons said.

“There’s no turning back,” he said, “because climate change isn’t going away.”