US President Donald Trump has withdrawn the US from dozens of international organisations, including many that work to combat climate change.
Nearly half of the 66 affected bodies are UN-related, including the Framework Convention on Climate Change - a treaty that underpins all international efforts to combat global warming.
Groups working on development, gender equality and conflict - areas the Trump administration had repeatedly dismissed as advancing globalist or woke agendas - are also included.
The White House stated the decision was taken because those entities no longer serve American interests and promote ineffective or hostile agendas.
The memorandum was signed on Wednesday following a review, with the White House describing the organisations as a waste of taxpayer dollars.
These withdrawals will end American taxpayer funding and involvement in entities that advance globalist agendas over US priorities, it said in a statement.
Alongside the UN Framework Convention on Climate Change, the US has also withdrawn from the Intergovernmental Panel on Climate Change (IPCC) - the world's leading authority on climate science that compiles respected reports on the science of rising global temperatures.
Sources within the organisation expressed concern about the potential impact of the Trump administration's withdrawal on US scientists involved in producing the body's next set of studies.
The White House has already blocked US scientists from attending a meeting in China.
Restrictions on travel or participation of US researchers could significantly delay the release of the next set of IPCC reports, including key guidance for governments on tackling climate change.
Non-UN organisations affected by the US withdrawal include those focused on clean energy cooperation, democratic governance, and international security, such as the International Solar Alliance, the International Institute for Democracy and Electoral Assistance, and the Global Counter-Terrorism Forum.
Trump has previously attacked many multilateral organisations, stripping them of funds and rejecting the scientific consensus of man-made climate change as a hoax.
While the US constitution allows presidents to join treaties with the Senate's approval, it does not specify the withdrawal process, uncertain if future presidents can reverse Trump's decision easily.
These withdrawals follow Trump's earlier exits from the Paris Climate Agreement and a refusal to send a delegation to the COP30 climate summit in Brazil.
European leaders have criticized the latest decision, warning it will weaken global cooperation. EU climate commissioner Wopke Hoekstra stated that the UNFCCC underpins global climate action and called the US retreat regrettable and unfortunate.
A member of the US-based non-profit advocacy group, Union of Concerned Scientists, described the step as a new low, with senior policy director Rachel Cleetus arguing it signals a dangerous trend towards undermining global cooperation and scientific integrity.
