The 1992 UNFCCC serves as the international structure for efforts by 198 countries to slow the rate of rising climate pollution. It has universal participation. The U.S. was the first industrialized nation to join the treaty following its ratification under former President George H.W. Bush — and it will be the only nation ever to leave it.

Among the groups from which the U.S. withdrew are two prominent climate organizations — the Intergovernmental Panel on Climate Change (IPCC) and U.N. Framework Convention on Climate Change (UNFCCC).

That included dangerous heat waves, which the WWA said were the world's deadliest extreme weather events in 2025. The researchers said some of the heat waves they studied in 2025 were 10 times more likely than they would have been a decade ago due to climate change.

The United States' decision to withdraw from the United Nations' key climate treaty is a "colossal own goal" that will harm the U.S. economy, jobs and living standards, United Nations climate chief Simon Stiell said on Thursday.

When engineers and planners design roads, bridges and dams, they rely on hydrological models intended to protect infrastructure and communities from 50- and 100-year floods. But as climate change increases the frequency and severity of floods,

President Trump's decision to withdraw the U.S. from 66 major global organizations includes United Nations talks on climate change and the oceans.

The EU regretted the decision by the United States to withdraw from the U.N.'s key climate treaty (UNFCC), EU Climate Commissioner Wopke Hoekstra said on Thursday.

On Wednesday, President Trump announced he was withdrawing the U.S. from the principal treaty for international cooperation on climate change.