In January 2026, the United States formally completed its withdrawal from the Paris Agreement (and WHO), the global treaty under the UN Framework Convention on Climate Change (UNFCCC) designed to coordinate international efforts to reduce greenhouse gas emissions. The Paris Agreement withdrawal takes effect one year after formal notification, and the U.S. had initiated this process shortly after President Trump’s inauguration in 2025. The withdrawal means the U.S. will no longer be bound by the reporting and transparency mechanisms that countries undertake under the Paris Agreement, and could cease providing emissions inventories and climate finance contributions, such as to the Green Climate Fund — a multilateral mechanism to support mitigation and adaptation in developing countries.

EPA: Rolling Back Climate and Pollution Protections

Moreover, since early 2025, the US Environmental Protection Agency (EPA) has undergone a profound shift. A series of policy changes, deregulatory moves, and scientific rollbacks have fundamentally altered its role in climate and environmental protection.

In February 2026, the EPA under Administrator Lee Zeldin repealed the long-standing “endangerment finding”, a 2009 scientific determination that greenhouse gases — such as carbon dioxide and methane — pose a risk to human health and welfare. This finding provided the legal foundation for federal greenhouse gas regulations under the Clean Air Act, including vehicle emissions standards and other climate policies. Now, federal control of greenhouse gas emissions is effectively dismantled: major vehicle emissions limits and power plant standards can no longer be justified under the Clean Air Act.

Legal uncertainty and challenges are underway: environmental and health advocacy groups have filed lawsuits in the D.C. Circuit Court of Appeals seeking to block the policy change, arguing it contravenes the Clean Air Act and scientific consensus.

Rollback of Mercury and Toxic Emissions Rules

In February 2026, the EPA also weakened the Mercury and Air Toxics Standards (MATS), a rule that had limited emissions of mercury, lead, arsenic, and other harmful pollutants from coal-fired power plants. The rollback reinstates older 2012 standards and eliminates tighter updates implemented under prior administrations. Critics warn this move will increase mercury and other toxic pollutants, particularly affecting children’s developmental health and exacerbating respiratory illnesses, while proponents argue it will lower costs for coal operators.

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Earlier regulatory exemptions allowed dozens of coal and chemical plants to bypass emissions rules altogether — often through processes that environmental groups described as exploiting loopholes designed to benefit industry at the expense of public health.

Under the Trump administration, the EPA has reversed decades of climate and environmental regulation, from dismantling the scientific basis for greenhouse gas controls to rolling back pollution limits on toxic emissions. The U.S. exit from the Paris Agreement compounds these changes on the international stage, weakening global cooperation just as climate impacts accelerate.

On their website, EPA published an article that summarises their efforts, President Trump and Administrator Zeldin Deliver Single Largest Deregulatory Action in U.S. History, stating:

Referred to by some as the ‘Holy Grail’ of the ‘climate change religion,’ the Endangerment Finding is now eliminated. The Trump EPA is strictly following the letter of the law, returning commonsense to policy, delivering consumer choice to Americans and advancing the American Dream.

These deregulatory shifts not only affect the pace of global climate action but also have tangible consequences for air quality, public health, environmental justice, and long-term policy certainty — both in the United States and globally.