UN Climate Report Puts U.S. Exit in Warming Forecast

The United Nations Environment Programme says the United States’ withdrawal from the Paris Agreement and rising emissions have worsened the world’s warming outlook. Governments’ current pledges still fall short of the pact’s temperature goals. Under the climate plans countries have submitted, the planet would be 2.6 degrees Celsius (4.7 degrees Fahrenheit) hotter than pre-industrial times by 2100.

Published on October 21, 2026, the report says projected warming under those pledges is about two-tenths of a degree Fahrenheit (0.1 degrees Celsius) higher than the same science team’s forecast last year. If countries make no further changes beyond their existing policies, warming would reach 2.8 degrees Celsius (5 degrees Fahrenheit) above the last half of the 19th century—the same projection as last year.

National pledges, global targets

Both projected outcomes exceed the 2015 Paris climate pact’s goal of keeping warming below 2 degrees Celsius (3.6 degrees Fahrenheit), and preferably limiting it to 1.5 degrees Celsius (2.7 degrees Fahrenheit). The report assesses national emissions plans and their likely effect; it doesn’t describe any transfer of formal authority from national governments to the United Nations.

The world is now about 1.4 degrees Celsius (2.5 degrees Fahrenheit) above pre-industrial levels. United Nations officials have acknowledged there’s no way to meet the 1.5-degree goal they had embraced. Instead, they’re hoping to limit warming to about 1.8 degrees Celsius (3.2 degrees Fahrenheit), then remove enough carbon dioxide from the air to bring temperatures back down to 1.5 degrees.

U.S. emissions and the revised forecast

The report links its worse outlook to the U.S. withdrawal from the Paris Agreement and revised estimates of historical emissions. U.S. emissions increased last year, while all other top 20 major economies either reduced carbon pollution or slowed the growth in emissions from burning coal, oil and gas.

The report said the U.S. increase totaled 133 megatons of carbon dioxide equivalent, driven by increased electricity demand and a rebound of coal power generation. Of the 124 countries that increased emissions in 2025, the United States accounted for 70% of the added 189 million tons of carbon dioxide. The report also said 63 countries decreased emissions, including most European nations.

Anne Olhoff, the report’s lead author and director of UNEP Copenhagen Climate Centre, said the U.S. policy change will likely add one-tenth of a degree Celsius (nearly two-tenths of a degree Fahrenheit) to global temperatures by the end of the century. Australian climate scientist Bill Hare, CEO of Climate Analytics, said the United States is going “hell-for-leather trying to block renewables while actively promoting and subsidizing dirty coal.” Hare wasn’t part of the report, but he and several other outside scientists said it was scientifically sound.

The costs cited by researchers

Hare said the additional tenth of a degree would push 140 million more people “into dangerously hot conditions” and increase the odds of the collapse of the Amazon rain forest or the ice sheets in Greenland and Antarctica. University of Pennsylvania climate scientist Michael Mann said it would cost the world and shave about $1.2 trillion from the global economy.

Mohamed Adow, director of Power Shift Africa, said the forecast has consequences for people around the world, including vulnerable communities in Africa. United Nations Secretary-General António Guterres said the world is falling “dangerously short” of its goals, “but we have the tools to change course and pull back from the brink.” UNEP Executive Director Inger Andersen said global carbon emissions must fall 18% by 2030 and 69% by 2040. The report centers on emissions, national climate plans and temperature projections; it provides no migration or demographic figures.