The planet has already warmed to a level unprecedented in human history. The election could determine whether the next president will respond.

Global climate pollution is already beginning to reshape the United States. In Phoenix, temperatures this year spent 70 days above 110 degrees. Hurricanes hit the Southeast, and back-to-back storms killed more than 200 people. And cities across the continent were choking under the foul smoke billowing into the air from wildfires on the West Coast.

Americans are just beginning to respond to these changes. President Joe Biden has taken the strongest action yet to combat climate change, pumping $1.6 trillion into the economy to fund green power plants, vehicles and factories.

Today, the elections come just as these investments are coming to fruition. The outcome of the fight between Vice President Kamala Harris and former President Donald Trump could determine whether they continue.

“There are a lot of issues in this cycle where the contrast is quite stark, like on abortion, for example, but climate change is one of those issues where the contrasts couldn’t be clearer,” said Leah Stokes, professor at the University. of California, Santa Barbara, who advised the Biden administration. “One is used to attacking big polluters, and the other is in the pocket of big polluters. »

The two candidates lead coalitions that could not be more different. Harris, who provided the deciding vote for passage of the Inflation Reduction Act, offers continuity in Biden’s approach: massive subsidies for renewable energy coupled with some modest limits on fossil fuels.

Trump, who has long called climate change a “hoax,” has promised to revitalize the approach he took in his first term: freeing up oil and gas development, repealing pollution rules and downgrading the federal support for renewable energy.

“The ocean is going to rise,” Trump said at a rally in Milwaukee on Friday. “Who cares?” »

In their only debate last month, Harris said Americans were already struggling with higher home insurance premiums because of extreme weather caused by climate change.

“I am proud that as Vice President, over the past four years, we have invested a trillion dollars in a clean energy economy, while increasing domestic gas production to historic levels,” she declared.

During Trump’s first term, internal “resistance” from career employees at agencies such as the EPA slowed his conservative agenda, said Steve Milloy, a lawyer who served on Trump’s transition team at the EPA in 2016. If Trump wins this time, anyone slowing down his priorities will be removed as an obstacle, Milloy said.

“The resistance got the better of Trump 1.0 in many ways, and I think people are wiser now,” he added. “There’s going to be a lot of work to do pretty quickly.”

The elections are taking place against the backdrop of a rapidly warming world. Global temperatures have risen by a a little more than 1 degree Celsius compared to pre-industrial levels. Scientists I think the world is seven years old at current emissions levels before global temperatures exceed 1.5°C and 28 years before temperatures exceed 2°C.

The eclipse of these thresholds comes with the risk of more frequent storms like Hurricane Helene, which swept through Florida with winds of 140 mph and dumped more than 30 inches of rain on parts of North Carolina end of September. That would mean even higher temperatures than Las Vegas experienced last month, when the city recorded six days of triple-digit temperatures. Before that, the city had only experienced six days of 100-degree temperatures in October — since 1937.

Whoever wins, the United States is not on track to meet the climate goals set by Biden. The president has promised to reduce emissions by at least 50% from 2005 levels by 2030. But most forecasters think the United States will fail of this brand, even as the country sets records for solar energy installations and electric vehicle sales.

“We unfortunately need to do a lot more because we are not on track to meet the pollution goals proposed by the Biden and Harris administration,” Stokes said.

“The IRA is just getting started”

Enacting the IRA in 2022 represented the federal government’s first major attempt to bring runaway climate pollution under control. The law departs from Democrats’ previous attempts to reduce greenhouse gas emissions. Instead of regulating carbon pollution, the law hands out money to consumers and businesses to go green.

This approach partly reflects political realities. Democrats did not have a sufficient majority in the Senate to pass non-budget measures. But it also shed light on a new theory of climate action.

“If a law includes a carrot, you immediately create a voter base that wants to preserve it. If a law includes a stick, you immediately create a constituency that wants to get rid of that law,” said Rep. Sean Casten, an Illinois Democrat who is outspoken on climate issues.

Two years later, the IRA can boast a complicated legacy. This sparked a wave of green investment. The country installed more large-scale solar power in the first nine months of 2024 (16.8 gigawatts) than in any year except 2023, when it installed 19 GW, according to the Energy Information Administration. Electric cars have reached almost 9 percent of vehicle sales in the third quarter of 2024, a record. And companies are exploring plans to make ammonia to fuel cargo ships, powering steel mills with a mixture of hydrogen and natural gasAnd power planes with low-carbon fuels.

Yet much of the impact of this law has yet to be felt. A POLITICO investigation revealed that manufacturers announced the creation of 555 factories to manufacture clean energy technologies following the passage of the IRA. While 230 of them have announced plans to start operations by the end of this year, less than half are operational.

“The IRA is just beginning to be implemented in the real world,” said Adrian Deveny, who helped write the IRA as a former aide to Senate Majority Leader Chuck Schumer. “A lot of this is because companies are waiting to see what happens. If Trump wins, businesses will be very nervous about making these investments because he has promised to repeal the IRA.”

Even though a Harris victory could salvage policies started under Biden, her ability to expand climate action faces serious obstacles — especially if Republicans retain control of one or both chambers of Congress, as they are favored .

If she lacks a friendly Congress to pass more climate laws, Harris’ ability to reduce emissions through executive action would also run up against a skeptical Supreme Court, whose conservative majority has already exercised its power against climate rules.

Harris “would find herself in an economy halfway through decarbonization, with many open questions about who benefits and who doesn’t,” said Craig Segall, vice president of Evergreen Action, a policy and defense.

During his first term, Trump dismantled much of former President Barack Obama’s climate legacy and appointed corporate lobbyists to head federal agencies. But many of his allies said Trump came to power unprepared to weaken regulatory agencies.

This time it would be different.

A new weapon of Trump: the Supreme Court

Two key conservative groups, the America’s premier policy institute and the Heritage Foundation, have spent years organizing an action plan with the goal of ensuring that government climate and clean energy policy is decimated for a generation.

A second Trump administration could also prepare for a series of lawsuits from environmental groups to slow down his agenda, Milloy said. There is a plan for that, he said, which involves setting “litigation traps.”

That means the Trump administration could attempt to bring legal cases to the Supreme Court and its 6-3 conservative majority. Winning cases before the nation’s highest court could establish a legal safety net that would be used to impose even more regulations, he said.

“I think it’s going to change the battlefield in the courts a little bit, and I also think Trump 2.0 will be a little smarter than Trump 1.0, so I think the Greens may fall into legal traps when they try to litigate this stuff,” Milloy said.

But Trump’s ability to slow down the energy transition would also come up against real limits. Just as in his first term, when cheap natural gas helped reduce U.S. emissions following the closure of coal-fired power plants, the economics of renewable energy and fossil fuels will determine how quickly the U.S. will reduce climate pollution.

Weakening or destroying the Inflation Reduction Act is not the winning policy outcome Trump thinks it is, said Ali Zaidi, Biden’s national climate adviser. He noted that House Republicans have tried unsuccessfully to repeal part or all of the law dozens of times, and that a number of Republican lawmakers have called on Trump to preserve the law.

“I think it’s deeply unpopular, not only in the real world, but also in the Washington bubble, where 50 votes failed to reach that goal in the House and a dozen and a half House Republicans House sent a letter to the president. saying, ‘Maybe we should stop trying to blow up our economic success,'” Zaidi said.

In a crucial battleground state, a top lawmaker said the stakes have already become clear to voters. Michigan’s aggressive climate laws were built on billions of dollars in IRA climate funding, said Michigan House Speaker Pro Tem Laurie Pohutsky. When she surveys voters, Pohutsky hears the problem playing out: “It’s something that people who are showing up at the doors are very excited about. »

“We have done historic and pioneering work here in Michigan,” she continued. “And at the same time, our (Republican) counterparts refuse to even acknowledge that climate change is happening – while Michigan homes are flooded and we face unprecedented weather events.”

“The comparisons,” Pohutsky added, “are really striking.”

Journalist Corbin Hiar contributed.