As global warming continued to reshape Earth’s climate, the planet’s oceans reached record high temperatures for the third year in a row in 2025. Some northern forests and tundra released more carbon dioxide than they absorbed. And the Greenland Ice Sheet lost about 129 gigatons of ice, enough to form a cube of ice about three miles wide on each side.
Those were among the findings in the 2025 State of the Climate report, released Monday by the American Meteorological Society and led by scientists at the National Oceanic and Atmospheric Administration.
The report identified continued burning of fossil fuels as the primary source of record-high greenhouse gas levels, which are raising global temperatures and intensifying extreme weather. In Europe, for example, average temperatures have risen about 3.6 degrees Fahrenheit since the 1960s, while extreme high temperatures have shot up by as much as 18 degrees Fahrenheit.
The findings carry added significance in light of an advisory opinion on climate change issued last year by the International Court of Justice, which concluded that countries may be liable for cross-border climate damage they knowingly cause or fail to prevent. As a result, governments that continue to promote fossil fuel use face increasing legal scrutiny and could be held responsible for ongoing and future climate-related harm.
“Anyone who still doubts the reality or severity of the climate crisis needs to read this report,” said climate scientist Jennifer Francis, who studies Northern Hemisphere climate extremes at the Woodwell Climate Research Center. Francis did not contribute to the report.
The report, she said, “underscores our collective failure in stemming human-caused climate warming and related impacts,” including “worse and more frequent heat waves, flooding, droughts, wildland fires, and disruptions to all life on Earth.”
The time to slow the changes is running dangerously short, she said, adding that “many leaders continue to ignore the warning bells.” Despite widespread public support for policies that protect the climate, many countries have expanded fossil fuel use, even since signing the 2015 Paris Agreement to limit human-caused warming.
The report foreshadows the even more intense climate extremes erupting around the world, from the March heatwave in western North America to extreme drought and wildfires in Europe this summer that have already caused more than $3 billion of economic damage.
The report’s key takeaway is that climate extremes that impact communities and economies “show no signs of diminishing,” said Alan Sealls, president of the American Meteorological Society. That means continued climate disruptions, he said, adding that the rising intensity and persistence of extremes shouldn’t be underestimated “compared to what the past delivered.”
Finally, he said, “Take personal action in becoming more resilient and encourage your political representatives to protect and fortify your community, knowing the changes that are happening.”
In 2025, “high humidity heat extremes occurred with near-record frequency and intensity,” co-authors and NOAA scientists Jessica Blunden and James Reagan wrote in the report’s executive summary. “These extremes can lead to dangerous heat-related illnesses.” When both the temperature and humidity are high, the air can’t absorb perspiration, so the human cooling system breaks down, making it impossible to survive without shelter or a mechanical cooling system.
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The findings also showed that overall global cloudiness in 2025 was the second-lowest since the start of the satellite record in 1980, “which means that more sunlight than usual reached Earth’s surface,” the authors wrote. It’s a critical measurement because recent research has shown that a decline of bright clouds that reflect heat back to space account for part of the recent acceleration of warming.
Not only were there fewer clouds, land surfaces continued to darken in 2025 because of wildfire-scorched land, heatwaves and reduced snow cover, all linked to persistently high temperatures. According to the report, “The darker the surface, the more sunlight is absorbed, which creates localized heating.”
Oceans absorb about 90 percent of the “excess heat” from human-caused warming, which manifested in marine heatwaves that were observed over 87 percent of the planet’s oceans last year, while marine cold spells reached their lowest occurrence on record, the report found. At the same time, ocean waters keep acidifying, which threatens marine life, and have lost oxygen at the rate of 0.45 percent per decade since 1965 due to “warming, reduced ventilation, ocean circulation changes, and enhanced biological respiration.”
The report doesn’t use the term global warming, but “is pretty clear on the fact that the warming and associated impacts are caused by greenhouse gas emissions,” climate researcher Michael Mann, director of the Penn Center for Science, Sustainability, and the Media at the University of Pennsylvania, said via email.
The scientific facts presented in the annual climate review counter climate disinformation pushed by the Trump administration as part of “the bad faith assault on climate science by polluters and their abettors, which began decades ago,” said Mann, who did not contribute to the report. Science Under Siege, a book Mann co-authored with Peter Hotez, a vaccine and tropical disease researcher at Baylor University, outlines how the attacks have been “a long-term project of the right that is now paying dividends for them.”
Mann said those attacks are dangerous to the public because they threaten the good-faith reliance on facts and evidence that shape public policy. The “firehose of politically-motivated antiscience disinformation,” he added, “undermines our ability to address any of the major threats, challenges, and crises we face, the climate crisis paramount among them.”
Colorado State University atmospheric scientist Scott Denning, who did not contribute to the report, wrote via email that every chapter “shows the very serious impacts of our self-destructive reliance on carbon combustion.”
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Reporter, Austria
Bob Berwyn is an Austria-based reporter who has covered climate science and international climate policy for more than a decade. Previously, he reported on the environment, endangered species and public lands for several Colorado newspapers, and also worked as editor and assistant editor at community newspapers in the Colorado Rockies.
