UN Report Flags U.S. as Top Emissions Driver

The United States added 133 megatons of carbon dioxide equivalent in 2025, more than any other country, according to a United Nations report. That figure represented 70% of the emissions increase among countries whose emissions rose. It’s a number that will draw attention in capitals from Washington to Brussels.

The report attributes the jump to two main sources: higher electricity demand and a rebound in coal power generation. Those forces pushed American emissions up even as most of the world moved in the other direction. The 124 countries that increased emissions added 189 million tons of carbon dioxide in 2025. Sixty-three countries, including most European nations, reduced theirs.

Where the U.S. Stands

The United States was the only major economy that failed to reduce its carbon pollution or at least slow the growth of emissions from burning fossil fuels. Every other country in the top 20 major economies either cut its pollution or slowed its rise. That’s a stark contrast, and the report doesn’t soften it. A country with the world’s largest economy stands alone among its peers on this measure.

The United Nations Environment Programme’s updated calculations offer a sobering outlook. If countries meet their submitted climate plans, Earth will likely warm another 2.2 degrees Fahrenheit (1.2 degrees Celsius) above current temperatures. That’s about two-tenths of a degree Fahrenheit (0.1 degrees Celsius) higher than the same science team projected last year. The report blamed the worsening picture on "the formal withdrawal of the United States of America from the Paris Agreement and revised estimates of historical emissions."

The Global Picture

The numbers get harder to ignore when you look further out. If countries meet their climate plans, the globe would be 2.6 degrees Celsius (4.7 degrees Fahrenheit) hotter than pre-industrial times by 2100. On the current path without national promises, warming would reach 2.8 degrees Celsius (5 degrees Fahrenheit) above the temperatures of the last half of the 19th century, unchanged from last year’s projection. Both projections exceed the 2015 Paris climate pact’s goal of keeping warming below 2 degrees Celsius (3.6 degrees Fahrenheit), preferably 1.5 degrees Celsius (2.7 degrees Fahrenheit).

The world is now about 1.4 degrees Celsius (2.5 degrees Fahrenheit) warmer than pre-industrial times. United Nations officials have conceded that limiting warming to 1.5 degrees is no longer possible. They’re now hoping to hold it to about 1.8 degrees Celsius (3.2 degrees Fahrenheit), then pull enough carbon dioxide out of the air to bring temperatures back down to 1.5 degrees.

Official Responses

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 cutting global carbon emissions by 18% by 2030 and 69% by 2040 "is the only way that we can get back to a semblance of a reality that is still largely manageable without major impacts and therefore that makes every sense."

Climate scientist Adelle Thomas, vice chair of a United Nations scientific assessment on climate impacts, wasn’t part of the study. She offered a blunt read: "The report's message is clear. 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."

Report lead author Anne Olhoff, director of UNEP Copenhagen Climate Centre, put a number on the U.S. policy change. It would most 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, which measures countries' climate-fighting plans, was far more pointed. He said the United States is "hell-for-leather trying to block renewables while actively promoting and subsidizing dirty coal — and its diplomacy is trying to make other countries also pull back on action." Hare, who wasn’t part of the U.N. report, added that it was scientifically sound. "It is looking at the fire, denying there is a fire, and then pouring more petrol on it."

Mohamed Adow, director of Power Shift Africa, a climate organization, framed the stakes around vulnerable populations. "This report shows that America's retreat isn't just a political embarrassment. It has real consequences for the planet and for millions of people around the world." He added that "an extra tenth of a degree might sound insignificant, but in climate terms it is enormous."

Why This Matters:

The fiscal and market stakes can get overlooked in a debate often framed as purely environmental. Hare estimated the extra tenth of a degree would put another 140 million people "into dangerously hot conditions" and raise the odds of collapse for the Amazon rainforest or the ice sheets in Greenland and Antarctica. University of Pennsylvania climate scientist Michael Mann said the added warming would shave about $1.2 trillion from the global economy. Households and businesses would bear that cost, and Washington’s policy debate rarely prices it in with any precision.

Johan Rockstrom, director of the Potsdam Institute for Climate Impacts Research in Germany, warned the U.S. effect could be larger than the U.N. calculation, since other nations may ease their own efforts if the largest historical polluter does little. Malte Meinshausen, another Australian climate scientist, went further, saying the rest of the world is weary of "the damage that the U.S. is willingly doing to allies, multilateral structures, economic cooperation, disaster relief." Whatever one thinks of the science, the report makes clear that a single country’s emissions choices now ripple through the energy markets, trade relationships and diplomatic commitments of every other nation on the planet.