The United States has officially left the Paris Agreement on climate change for a second time under President Donald Trump.
Trump signed an executive order to leave the accord on the day of his inauguration on January 20, 2025.
The Paris Agreement aims to limit global warming to well below 2 degrees Celsius compared to pre-industrial times - ideally to just 1.5 degrees.
According to the UN climate secretariat, the withdrawal takes effect on Tuesday, exactly one year after the notice was received by the United Nations.
The US has already largely stepped back from climate diplomacy, including by missing the UN Climate Change Conference (COP30) in the Brazilian city of Belém last November.
The withdrawal means the US no longer considers itself bound by commitments to curb global warming. In addition, the withdrawal leaves a significant funding gap, including for climate mitigation and adaptation support that is especially important for poorer countries.
The US is the world's second-largest emitter of greenhouse gases after China, meaning the decision will have far-reaching consequences for the climate.
Based on current global climate policies, the UN estimates the world is heading towards 2.8 degrees of warming above pre-industrial levels by the end of the century.
The US withdrawal is expected to contribute an additional 0.1 degrees of warming, according to UN estimates. Climate researchers say every 0.1 degree significantly worsens climate impacts.
During his first term in office, Trump also led the US out of the Paris Agreement, before the country rejoined under his successor, Joe Biden.
In recent weeks, the Trump administration also announced plans to withdraw from the UN Framework Convention on Climate Change - the backbone of international climate policy - and from the Intergovernmental Panel on Climate Change (IPCC).
