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As US officials at COP28 try to convince other nations the world’s biggest economy will support them by cutting carbon emissions and building renewables, they’re being undermined by someone who isn’t even at the climate summit in Dubai.

The assurances are being made under a shadow cast by former President Donald Trump — and the prospect that Americans will award a second term to the Republican who yanked the US out of the Paris Agreement, dialed back green regulations and reneged on funding commitments to help poor countries bearing the brunt of global warming.

Even if Joe Biden remains in office after the 2024 elections, Republican gains in Congress could put some of the country’s clean energy incentives in jeopardy and make it impossible for the US president to deliver a promised $11 billion in climate finance. It threatens a core element of US credibility in the climate talks, since financial support and carbon cuts from the world’s second-largest emitter are a major determinant of how ambitious the world can be in phasing out fossil fuels and scaling up alternatives.

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“It would be sad to see the US take a step back from where they’re leading at the moment,” said Samoa’s climate minister, Toeolesulusulu Cedric Pose Salesa Schuster. He leads a negotiating bloc of small island nations most vulnerable to climate change and said it’s a “concern” that US financial support to help them prepare for more extreme weather will dry up like they did during Trump’s presidency.

The US has long been viewed an unreliable but necessary ally at the annual climate talks. The Senate failed to ratify the Kyoto treaty that underpins the negotiations and the final $1 billion installment of a 2014 pledge to add $3 billion to a UN climate fund hasn’t been met. Negotiators have grown uncomfortably familiar with a political system that means US commitments often require agreement from Congress or can be reversed by future presidents.

While US companies face “public pressure to act despite the political divide,” the risk that government policy will pivot hangs over the UN talks, said Paul Bledsoe, a former Clinton White House climate aide who lectures at American University. “Republican recalcitrance on climate action and the specter of Trump's return to the White House means US negotiators inevitably encounter extra skepticism regarding long-term climate promises.”

Policies at Risk

To negotiators in Dubai, the risk feels especially acute. Some House Republicans want to repeal broad swaths of last year’s sweeping climate law, with a particular focus on Inflation Reduction Act tax credits worth up to $7,500 toward the purchase of new electric vehicles. Just days ago, the House of Representatives passed legislation that would block the Environmental Protection Agency from finalizing a pollution rule that would compel automakers to ensure two out of every three cars and light trucks sold in 2032 are electric.

The world already knows what happens when the federal government sidelines workers and forgoes the economic upside of clean energy "to serve some base political objectives," said White House National Climate Advisor Ali Zaidi. "At the end of the day, leadership matters. And you've got House Republicans who’ve put up countless efforts to try to roll this back.”

US officials have been telling foreign counterparts that much of the Inflation Reduction Act will endure, in part because it is already spurring plans for new manufacturing plants and renewable power projects in deeply red states.

“A lot of these investments are front-ended and already deployed, so they simply cannot be undone,” said US Senator Brian Schatz, a Democrat from Hawaii who joined a group of lawmakers in Dubai on Saturday. “It’s going to be really hard to undo this because we barbed the hook, and the thing is really popular and working beyond I think most people’s reasonable expectations.”

Read More: Red States to Reap the Biggest Rewards From Biden’s Climate Package

The associated jobs and economic benefits will heighten the political risk for Republicans looking to repeal that support, said John Podesta, senior advisor to the president on clean energy innovation and implementation.

“Once these announcements are made, steel goes into the ground and jobs are created — all across the country,” he said. “When that happens, the value in those communities of keeping those jobs and keeping that renaissance and manufacturing is going to very, very strong.”

The law dedicates some $370 billion to environmental and climate initiatives, with some earmarked for grants and loan guarantees that a future president would have wide discretion to stall. But much of its support comes in the form of tax credits that have proven popular with renewable developers as well as oil companies.

Darren Woods, the chief executive officer of Exxon Mobil Corp., called the IRA “a good first step” in building markets for low- and zero-emission technology.

“Government has a very important role to play in this space,” he said in an interview at COP28. "If the world 's going to make progress in reducing emissions and get to net zero we've got to have good policies to kick start that and to begin to establish the market.”

Defending Climate Progress

Still, the US Treasury Department plays is key in deciding what projects qualify for electric vehicle and clean energy tax credits, and a future administration could change regulations so they’re harder to claim. Other climate rules imposed under Biden — including new and proposed EPA regulations throttling emissions from power plants, oil wells and automobiles — also could be at risk of a rewrite. During Trump’s first term, the federal government relaxed an array of Obama-era climate regulations. Federal courts reversed some, but not all, of those moves.

Michael Regan, the head of the EPA, said the agency has learned from experience and is building rules that can endure. “Legal defensibility and durability has been front and center in our design process,” he said. “Technology has just evolved, and the markets are a little bit more accepting, so we believe that combination is going to land us in the sweet spot.”

California Attorney General Rob Bonta assured COP attendees that like-minded states are prepared to defend Biden climate moves in court and keep advancing their own, subnational policies to propel clean energy and carbon cuts. “No matter who the federal government is and what they do, we will continue to push forward,” he said.

Some promises may be harder to keep. Biden’s vow of more than $11 billion in international climate finance by 2024 and a new $3 billion for the UN Green Climate Fund depend on support from Congress. The administration managed to muster at least $9.5 billion in climate finance this year, even with Republicans in charge of the House. But Trump ripped up checks for the Green Climate Fund during his first term, and climate finance reached just $1.5 billion in 2021.

There’s also the fear Trump could irrevocably damage the credibility of the 2015 global climate deal by pulling out for a second time, said Michai Robertson, a special adviser for the small island states. “It would make the Paris Agreement a joke,” he said.

The US climate envoy, John Kerry, has focused his COP28 talking points on the private sector, arguing that companies won’t reverse investments in new clean manufacturing lines and contracts for renewable power.

While a climate-denying president could have an impact, “they are not going to stop what is happening,” Kerry said. “There’s no going back.”

--With assistance from John Ainger.

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