President Biden used the waning hours of a White House climate summit to hammer home a message aimed as much at Americans as at the dozens of world leaders he had convened: Combating the Earth’s warming is not simply a responsibility, but a chance to boost battered economies.

“Today’s final session is not about the threat climate change poses,” Biden said Friday morning from the East Room. “It’s about the opportunity that addressing climate change provides, an opportunity to create millions of good-paying jobs around the world in innovative sectors.”

Biden touted the new jobs that combating climate change could bring, including building electric cars, installing charging stations, upgrading schools and commercial buildings, constructing energy-efficient homes and producing solar panels and wind turbines.

When we invest in climate resilience and infrastructure, we create opportunities for everyone. That’s at the heart of our jobs plan that I proposed here in the United States,” Biden said. “It’s how our nation intends to build an economy that gives everybody a fair shot.”

Thursday’s marathon virtual summit was primarily intended to highlight a new U.S. pledge to make deep cuts to its carbon emissions this decade, mend the nation’s diplomatic reputation and rally other nations to embrace more ambitious climate goals of their own in coming months.

Friday’s session — which once again featured heads of state, business executives and labor representatives — was meant to underscore the administration’s assurances that combating climate change should not inflict economic pain, but rather help lift up communities across the country and the world.

Republicans for years have forced Democrats on the defensive by portraying climate action as a concession to fuzzy environmentalism at the cost of jobs for ordinary Americans. Biden is pushing hard to redefine the debate, arguing that renewable energy is at least as much an economic opportunity as an environmental imperative.

It’s a message that Biden has repeated over and over again on the campaign trail, in interviews, in speeches and in articulating the motivation behind his proposed $2 trillion infrastructure plan, which would include massive new investments in clean energy, electric vehicles and weatherization.

Biden’s pledge this week to cut U.S. greenhouse gas emissions 50 to 52 percent by 2030, relative to 2005 levels, would require far-reaching changes that impact how Americans power their homes, how they travel and even how they grow food.

To meet that goal, the administration ultimately must rely on assumptions about the future that are hard to guarantee. Will a sharply divided Congress, home to some Republicans who say such policies risk leaving behind communities that rely on fossil fuels, fund Biden’s proposals? Will future administrations keep in place any new regulations aimed at curbing emissions? And will such policies survive inevitable court challenges?

On Friday, those questions would have to wait.

President Biden has set ambitious benchmarks for the United States' role in combatting climate change. Here’s how the administration plans to do it. (Blair Guild/The Washington Post)

Biden lined up a cast of Cabinet members and enthusiastic business and labor figures to praise his jobs plan, highlighting the president’s message that building a carbon-free economy can create “good union jobs,” as administration officials said repeatedly this week.

Flanked by White House adviser Gina McCarthy, Transportation Secretary Pete Buttigieg and U.S. Trade Representative Katherine Tai, Biden listened as an electric school bus maker, a commercial building energy controls manufacturer, an electric grid expert and two union representatives reaffirmed their support for the president’s domestic strategy and legislation.

“There are no jobs on a dead planet,” said Sharan Burrow, general secretary of the International Trade Union. “We will work with everyone for a living planet.”

Buttigieg said that a majority of the “millions” of transportation jobs redesigning roads, laying rail lines and installing electric vehicle charging stations “will be available to workers without a degree,” a group that has suffered acutely during the pandemic-driven economic downturn.

“We are all in this together,” he added. “Pursuing a net-zero goal is not a zero-sum game.”

Former New York mayor Mike Bloomberg, who was appointed this year by the United Nations as a special envoy for climate ambition and solutions, underscored that mayors, governors and business leaders will play a central role in the push to reduce the nation’s emissions. After all, those cities and states continued to push forward climate action even during the Trump administration.

“Cities and businesses hold the key to defeating climate change,” Bloomberg said. “They are responsible for the vast majority of emissions. So helping them and incentivizing them to take action really is critical.”

Despite the upbeat talk about vast investments in burgeoning technologies and a potential tidal wave of new jobs, there were reminders of the difficult road to making such changes a reality.

Fatih Birol, head of the International Energy Agency, praised the many commitments from public and private officials during the White House summit. But he also warned that tangible action is the only way to alter the world’s current path toward worsening climate change.

“I will be blunt: Commitments alone are not enough,” Birol said at Friday’s summit. “We need real change in the real world right now. The data does not match the rhetoric, and the gap is getting wider and wider.”

He cited IEA findings published this week, which projected that global carbon dioxide emissions are set to rise by 1.5 billion tons in 2021 — the second-largest increase in history — as the world emerges from a pandemic-induced downturn.

Massive coal demand in the electricity sector will largely drive the emissions rise, according to the agency. National pandemic relief packages so far have not done enough to incentivize the needed shift toward cleaner forms of energy, he added.

“We are not recovering from covid in a sustainable way, and we remain on a path of dangerous levels of global warming,” he said.

Birol said reasons for optimism exist, from record numbers of solar and wind investments to increasing sales of electric vehicles. But he added that significantly bending the curve of global emissions will require more sweeping efforts, including the development of technologies that are not yet ready for the market.

Make no mistake,” he said, “this is a herculean task.”

Adding to that dose of realism were reminders that even as some climate activists have pressed Biden to move more quickly, many Republicans have not embraced his climate aspirations. Rather, they argue that too hasty a shift away from fossil fuels could harm U.S. competitiveness and hurt the very communities that the president says he wants to help.

Senate Minority Leader Mitch McConnell this week tweeted that Biden’s “zeal for costly climate policy at home is not matched by our biggest competitors.” China accounts for roughly double the greenhouse gas pollution of the United States, he noted, and has not yet demonstrated a commitment for the same rapid shift. “Democrats can kill U.S. jobs & industries with no real impact on global emissions,” he wrote.

Biden’s emphasis Friday on the opportunity climate change presents to create new jobs reflects his long-standing strategy of seeking to thread a difficult needle in climate politics. Dating back to his campaign, Biden has tried to embrace the goals of environmentalists in a way that doesn’t alienate labor unions and workers who depend on the fossil fuel industry.

His approach has produced mixed results, sometimes angering one side or the other. When he announced this year that he was rescinding the construction permit for the Keystone XL oil pipeline, for example, he got blowback from union leaders concerned about job losses.

In an interview Friday afternoon, Biden’s special climate envoy, former secretary of state John F. Kerry, said he viewed the two-day summit as a clear success, because it showed that the United States is serious about tackling climate change and because it will generate momentum for other nations to do the same.

“We saw presidential leadership trying to raise ambition, which is the essential element of any legitimate effort to deal with the climate crisis,” Kerry said, adding: “I think there are a lot of very serious conversations going on in capitals around the world, because of what President Biden convened this week.”

But overseas, as at home, Kerry reiterated that putting the nation and the world on a more sustainable trajectory cannot happen at a summit, but only what comes after it.

“The time for words is over,” he said. “There have to be actions.”

As he closed out the unprecedented White House summit Friday afternoon, Biden once more delivered the same message.

“The commitments we’ve made must become real,” he said. “Commitment without us doing it, it’s just a lot of hot air, no pun intended.”

John Wagner contributed to this report.