Donald Trump’s win in the US election earlier this month will bring sweeping changes across many areas of government policy – not least climate action.

When he takes office as US president from January, Trump is expected to pull the United States out of the Paris climate agreement again, as he did in 2017. In June, a campaign spokesperson told Politico that Trump would remove the US from the pact if he was re-elected.

During his election campaign, Trump claimed that “we don’t have a global warming problem”, and that climate change is a “hoax”. He has also talked about increasing fossil fuel production, using the slogan “Drill, baby, drill”.

In 2017, the impact of the withdrawal was limited. Under the rules of the treaty, the decision did not take effect until November 2020 and was swiftly reversed by Joe Biden when he took office a few months later. This time, Trump would only need to wait one year until the US is out of the agreement.

While president Biden’s negotiators have attended COP29 talks in Azerbaijan, nothing they agree to will be binding for the Trump administration.

Pulling out from the Paris agreement would make the US one of the only countries not to be a party to the 2015 pact, in which nearly 200 governments have made non-binding pledges to reduce carbon emissions. It is also significant as the US is the world’s second-largest emitter of greenhouse gases.

Trump could also try to withdraw the United States from the United Nations Framework Convention on Climate Change (UNFCCC), says Gautam Jain, senior research scholar in financing the energy transition at Columbia University. He notes that if the US withdrew from the 1992 treaty, which is the foundation for international climate talks, it would be “nearly impossible” for a future administration to rejoin because doing so would require the consent of two-thirds of the Senate.

“The reverberation of such a step would be felt around the world,” said Jain. “While the Paris Agreement is not legally binding and is based on trust and leadership, the stance taken by the world’s largest economy affects what other countries are willing to do.”

Energy policy rollbacks could face challenges

Trump has also said he would roll back Biden’s clean energy policies and focus on fossil fuels. This weekend, he nominated Chris Wright as energy secretary. Wright is the founder and CEO of Liberty Energy, a fracking and oilfield services company, who last year said in a video posted to his LinkedIn profile that “there is no climate crisis, and we’re not in the midst of an energy transition either”.

Trump has pledged to reverse Biden policies including subsidies for wind energy, as well as some of the Department of Energy and Environmental Protection Agency regulations that, according to the Trump campaign, prevent Americans from buying incandescent lightbulbs and gas stoves and limit water consumption by dishwashers and shower heads.

However, some believe that Trump may face more resistance on the issue of clean energy.

“Governors and representatives in Congress on both sides of the aisle have come to recognise that clean energy is a huge moneymaker and a job creator,” said Dan Lashof, US director at the World Resources Institute. “President Trump will face a bipartisan wall of opposition if he attempts to rip away clean energy incentives now.”

Jain also noted that: “It may be harder for him to eliminate the Biden administration’s massive investments in clean energy, which are interwoven with much-needed investments in infrastructure and manufacturing in the Infrastructure Investment and Jobs Act and the Inflation Reduction Act.

“Since both are laws that Congress passed, Trump would need majorities in both Houses to repeal them.”

Analysis from the Net Zero Industrial Policy Lab also suggested that rolling back Biden’s major climate policies could mean the US losing out on US$80bn of investment and cost up to $50bn in lost exports.

While for many the climate outlook for the US and beyond is bleak under Trump, Lashof tried to strike an optimistic tone.

“There is no denying that another Trump presidency will stall national efforts to tackle the climate crisis and protect the environment,” he said. “But most US state, local and private sector leaders are committed to charging ahead. And you can count on a chorus of world leaders confirming that they won’t turn their back on climate and nature goals.”