Five ways Trump’s climate rollback could affect the world

US President Donald Trump has thrown the weight of the federal government behind vehicles that burn gasoline rather than electric cars. Keystone

The United States has once again retreated from global climate cooperation under President Donald Trump, formally exiting the Paris Agreement for a second time, leaving key United Nations climate bodies and dismantling domestic environmental policies. Here are some of the key consequences and what they mean for countries like Switzerland.

A blow to international climate diplomacy and US influence

On January 7, the US announcedExternal link it was withdrawing from 66 international organisations, including several central to climate action such as the UN Framework Convention on Climate Change (UNFCCC), the treaty underpinning global efforts to curb warming that includes all countries among its members.

The White House argued the organisations “no longer serve American interests” and promote “ineffective or hostile agendas”. Trump has repeatedly dismissed climate change as a hoax.

The US is now the first and only country to leave the UNFCCC – alongside earlier withdrawals from the Paris Agreement in 2017 and 2025. The latest departure took effect on January 27.

“It is a more serious step definitely. The world loses a lot and it is very damaging,” Johan Rockstrom, director of the Potsdam Institute for Climate Impact Research in Germany, told Associated Press (AP).

Leaving the UNFCCC releases the US from obligations such as financing treaty work or reporting national emissions, weakening global monitoring efforts. While the withdrawal requires a year to complete, official US participation in UN climate forums had already been waning. Legal experts say it remains unclear whether Trump can unilaterally exit the convention.

Shifting geopolitical dynamics on climate issues

Although many regret the US retreat, experts stress it will slow but not reverse the global transition to clean energy. “International cooperation will not collapse because the UNFCCC has 195 members rather than 196,” Dr Joanna DepledgeExternal link of the University of Cambridge told the Carbon Brief website.

At the same time, it gives China and the European Union an opportunity to shape climate standards and clean-tech markets.

While regretting the withdrawal of the US from the Paris Agreement – the world’s second largest emitter, after China, and the largest historically – Swiss climate ambassador Félix Wertli said the 2015 climate treaty remains robust.

“No other country has announced its withdrawal, and the agreement still covers almost 90% of global emissions,” he told Swissinfo. “At the same time, the work carried out under the Paris Agreement is increasingly bearing fruit, and the move away from fossil fuels is in full swing. Renewable energies are developing faster than expected.”

Global clean energy investment nowExternal link exceeds $2 trillion a year, far outstripping spending on fossil fuels. Renewables accountedExternal link for more than 90% of new power capacity added in 2024, while electric vehicles represent around one in five new car sales worldwideExternal link. Low-carbon power makes up over half of generation capacity in ChinaExternal link and IndiaExternal link, while China’s exports of low-carbon goods and services toppedExternal link $20 billion in a single month last year.

US disengagement is also prompting others to step up. At last year’s COP30 in Brazil, Colombia and the Netherlands announced plans – alongside Pacific Island states – to host the first international talks on phasing out fossil fuels.

Global emissions targets become harder to achieve

The US exit raises the risk of higher global emissions and gives some countries political cover to delay climate action. The US accounts for roughly a quarter of historic CO₂ emissions and around 13% of annual emissions.

Reto Knutti, professor of climate physics at the Swiss federal technology institute ETH Zurich, called the US move “unfortunate, short-sighted but not surprising”. The immediate consequences may be manageable, he saidExternal link, but the deeper risk is eroding trust in international institutions, agreements and long-term goals.

“If treaties, commitments, partnerships and negotiations are treated as temporary conveniences that anyone can walk away from, we are in deep trouble,” said Knutti.

The exit comes as global warming nears 1.5° degrees Celsius (2.7° Fahrenheit) above pre-industrial levels. “We need to cut emissions globally by 5% per year,” Rockstrom said. “And exactly at that moment, the biggest player in the world steps out of the game.”

By early 2026, about two-thirds of countries had submitted updated 2035 climate targets, covering nearly 80% of emissions. Yet the UN Environment Programme (UNEPExternal link) estimates these would limit warming only to 2.3°–2.5°C this century, with the US withdrawal alone cancelling about 0.1°C of progress.

Switzerland aims to cut greenhouse gas emissions at least 65% by 2035 and reach net-zero by 2050.

At COP30, Brazil launched informal processes to establish roadmaps to phase out fossil fuels and to combat deforestation. Amid the US rollbacks, Wertli says Switzerland is backing these plans and “will take an active role in sending political signals and putting concrete measures in place to speed up progress toward both goals”.

Climate finance to poorer countries takes a hit

Trump’s aid freeze threatens major cuts to overseas spending on climate programmes. Analysts warnedExternal link last year that nearly a tenth of global climate finance could be at risk.

The US funding halt is expected to widen an already large financing gap for countries in Africa, Asia and small island states that depend on international support to cope with floods, droughts, heatwaves and rising sea levels.

Under Biden, the US scaled upExternal link climate finance to $11 billion (CHF8.6 billion) a year between 2021 and 2024. Trump has since frozen foreign aid and cancelled climate funding.

Before Trump Administration freezes to foreign aid, USAID provided about a third of US climate finance, reaching nearly $3 billion in 2023. The $4 billion pledged to the Green Climate FundExternal link (GCF), which supports climate adaptation and clean energy in developing countries, has also been scrapped.

Delia Berner, an international climate policy specialist at the Swiss NGO Alliance Sud, called the US withdrawal a “bitter blow” and said this makes Switzerland’s cooperation with other countries in the context of international climate financing even more important.

Berner added that poorer nations need far greater support to pursue climate friendly development, instead of becoming dependent on oil producing states. Switzerland endorsed a global target to mobilise $300 billion a year by 2035, but the Federal Council decided in December 2025 to postpone any action until 2027 – a decision she called “irresponsible”.

Impact on climate science

The US has also withdrawn from the Geneva-based Intergovernmental Panel on Climate Change (IPCC), the world’s leading climate science body. Historically, the US contributed about 30% of voluntary IPCC funding – around $67m – and provided expertise, data and leadership to its assessments used by governments.

The IPCC will continue its work without official US involvement but with several dozen US scientists still contributing voluntarily.

“Contributions from US scientists and institutions will remain a cornerstone for IPCC,” said Knutti.

Funding will come from elsewhere, he said, but reduced US participation could affect research, data sharing and the perceived weight of future reports.

Edited by Gabe Bullard/Veronica De Vore