U.S. State Retreat Deepens Climate Costs for Millions

The United States’ withdrawal from the Paris Agreement and rising emissions have worsened the United Nations’ climate outlook. The country accounted for 70% of added carbon dioxide emissions among nations whose emissions increased in 2025. A Wednesday report from the United Nations Environment Programme says the world is losing ground, as government decisions and power systems push costs onto people around the world.

Mohamed Adow, director of Power Shift Africa, said the U.S. retreat has consequences “for millions of people around the world.” He warned that an extra tenth of a degree Celsius means “more dangerous heat waves, more destructive floods, more failed harvests and more lives lost.” For vulnerable communities in Africa, he said, “every fraction of a degree matters.”

Who Controls the Course

If countries meet their submitted emissions-cutting plans, the report says, Earth will warm 2.6 degrees Celsius (4.7 degrees Fahrenheit) above pre-industrial levels by 2100. Without those national promises, warming would reach 2.8 degrees Celsius (5 degrees Fahrenheit)—the same projection as last year.

Both outcomes exceed the 2015 Paris climate pact’s goal: keep warming below 2 degrees Celsius (3.6 degrees Fahrenheit), preferably 1.5 degrees Celsius (2.7 degrees Fahrenheit). The world is already 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.

Now, officials hope 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. That hope sits alongside projections well above the pact’s limits.

The report links the worse outlook partly to the United States’ formal withdrawal from the Paris Agreement and revised estimates of historical emissions. U.S. emissions rose by 133 megatons of CO2 equivalent in 2025, driven by increased electricity demand and a rebound of coal power generation. All other top 20 major economies either cut carbon pollution or slowed emissions growth from burning coal, oil and gas.

The United States made up 70% of the added 189 million tons of carbon dioxide among 124 countries whose emissions increased in 2025. Sixty-three countries cut emissions, including most European nations.

Who Pays for State Choices

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” and using diplomacy to urge other countries to pull back. Hare wasn’t part of the U.N. report, but he and several other outside scientists said it was scientifically sound.

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. Hare said that increase would push an additional 140 million people “into dangerously hot conditions” and raise 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 the added warming would cost the world and shave about $1.2 trillion from the global economy. Johan Rockstrom, director of the Potsdam Institute for Climate Impacts Research in Germany, said the U.S. effect is probably larger than the United Nations calculates because other nations may ease their efforts if the world’s largest historical climate polluter does little to fight global warming.

Promises, Tools and Delay

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 to return to a reality “still largely manageable without major impacts.”

Climate scientist Adelle Thomas, vice chair of a United Nations scientific assessment on climate impacts, said, “We know what needs to be done. We have the tools to do it. And delay only makes the challenge more dangerous and more expensive for all.” Thomas wasn’t part of the study.

Australian climate scientist Malte Meinshausen said the rest of the world is “exhausted” by the damage the United States is willingly doing to allies, multilateral structures, economic cooperation and disaster relief. The report came out on October 21, 2026. The Associated Press said its climate and environmental coverage receives financial support from multiple private foundations and that AP is solely responsible for its content.