UN climate chief warns that a second Donald Trump term would be a catastrophe for planet Earth

The outgoing United Nations climate chief warned Monday that a victory by Donald Trump—or any other Republican ally of the fossil fuel industry—in the 2024 U.S. presidential election would represent a fatal setback for efforts to limit global warming to 1.5°C by the end of the century.

"Well, yes," Patricia Espinosa, executive secretary of the United Nations Framework Convention on Climate Change (UNFCCC), toldPolitico when asked whether Trump or another Republican president similarly hostile to climate action would spell doom for the Paris Agreement's lower-end warming target.

"Leadership was not there" on climate during Trump's four years in office, Espinosa said in an interview on the sidelines of the ongoing climate conference in Bonn, Germany.

"We didn't manage to get the same level of traction in the process," she added.

The prospect of a Republican win 2024 is highly unnerving for climate advocates, given the party's fealty to the fossil fuel industry and opposition to even the most basic emissions-reduction policies. It's not clear how other potential Republican presidential contenders—from Florida Gov. Ron DeSantis to Sen. Tom Cotton (R-Ark.)—would substantively differ from Trump on climate.

"The climate's always been changing," Trump said in a Fox News interview in March, pushing several denialist talking points.

During his four years in the White House, Trump formally withdrew the U.S. from the legally binding Paris accord, opened up the Arctic National Wildlife Refuge and other pristine lands and waters to drilling, and went on a sprawling deregulatory frenzy that rewarded the fossil fuel industry at the expense of the environment and public health.

The former president also packed his cabinet and other key posts with close friends of the fossil fuel industry.

Given his disastrous climate record, it's no surprise that the planetary consequences of another Trump term were a major topic ahead of the 2020 presidential election. Michael Mann, a leading climate scientist, warned months ahead of the contest that "a second Trump term is game over for the climate."

"If we are going to avert ever more catastrophic climate change impacts, we need to limit warming below a degree and a half Celsius, a little less than three degrees Fahrenheit," Mann said. "Another four years of what we've seen under Trump, which is to outsource environmental and energy policy to the polluters and dismantle protections put in place by the previous administration... would make that essentially impossible.”

President Joe Biden ultimately defeated Trump in 2020 and—within hours of being sworn in—moved to return the U.S. to the Paris Agreement. Scientists have been sounding the alarm for years that a breach of the treaty's 1.5°C threshold would mean even more devastating extreme weather, flooding, displacement, a mass coral reef die-off, and other harmful impacts.

While he won praise for rejoining the Paris accord, Biden's overall climate record has not exactly stoked activists who were—and still are—expecting bold action from the administration.

Just last week, Biden boasted that under his leadership "the United States is on track to produce a record amount of oil next year," adding that he is "working with the industry to accelerate this output" in an effort to rein in soaring prices at the pump.

Climate advocates have also voiced alarm at federal data showing that the Biden administration approved more permits for oil and gas drilling on public lands during its first year in power than the Trump administration did in 2017.

Meanwhile, the billions of dollars in renewable energy investments that Biden campaigned on remain stalled in the U.S. Senate largely due to Sen. Joe Manchin (D-W.Va.), a top ally of the fossil fuel industry.

"He can't be the Climate President when he refuses to play hardball with Joe Manchin and corporate politicians who have prevented the passage of a historic climate bill that will save lives across the country," Sunrise Movement executive director Varshini Prakash said in a January assessment of Biden's first year in the White House.

"Put simply, he needs to act with the urgency and courage that the climate crisis demands," said Prakash. "Doing anything less risks young people's support, and Democrats' already slim majorities in the House and Senate."