The US withdrawal from the Paris Climate Agreement: could it trump progress on climate change and health?

Climate news in the opening weeks of 2025 was extraordinary. The Mauna Loa Observatory reported¹ a CO₂ level of 425.4 ppm for the end of 2024—a one year increase of 3.5 ppm. This is the largest annual rise in over 70 years of monitoring. The World Meteorological Organisation confirmed that 2024 was the warmest year on record, at about 1.55°C above preindustrial levels.² Horrific wildfires ripped through Los Angeles, killing over two dozen people, destroying thousands of buildings, and incurring costs that may top USD 250 billion.³

These events unfolded alongside Donald Trump’s inauguration as US President. One of his first actions was an executive order withdrawing the US from the Paris Climate Agreement.⁴ This repeated an action he took during his first term, and that President Joe Biden reversed when he took office in 2021.

The US is the only nation to have withdrawn from the Paris Agreement. In doing so again, it joins just three other nations—Iran, Libya, and Yemen—as non members. The practical consequences of the US’s withdrawal are difficult to predict. The Paris Agreement does not require binding commitments to carbon emissions reductions. Accordingly, US withdrawal does not release the nation from any specific cuts. The financial consequences may be more tangible. Through the UN Framework Convention on Climate Change, rich countries have pledged contributions to poorer countries to help fight climate change—a commitment that reached USD 300 billion in 2024—but rich countries, including the US, have fallen far short on this commitment. With its withdrawal from the Paris Agreement, US contributions will presumably fall even further.

The intangible consequences of the US withdrawal will likely be more substantial: undermining international cooperation in the fight against climate change; reinforcing the perception of the US as an unreliable partner; forfeiting global leadership on climate change to other nations, especially China; and precluding US dominance in green technologies.

Perhaps more consequential than withdrawal from Paris is US domestic action on climate change under the Trump administration. Trump immediately moved to reverse many Biden-era policies related to climate change—expanding fossil fuel production on Federal land and waters; eliminating...