Charles Rotter
The Associated Press ran its story on the UN Environment Programme’s Emissions Gap Report 2026 under the headline “US is a big reason for the world losing ground in the fight against climate change, UN report says.” The size of the big reason turns up in the eleventh paragraph. Steve Milloy flagged it.
Report lead author Anne Olhoff, 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.
One-tenth of a degree, 74 years from now.
AP also says where that tenth sits:
The new calculations say that if countries do all they promise in the climate fighting plans they submitted to the United Nations, by 2100 the globe will be 2.6 degrees Celsius (4.7 degrees Fahrenheit) hotter than pre-industrial times. If the world continues on its current path — without national promises — it will be 2.8 degrees Celsius (5 degrees Fahrenheit) warmer than the last half of the 19th century, the same as last year’s projection.
So the tenth only shows up in the scenario where every country keeps every promise. The current-path number, the one built on what governments are actually doing, hasn’t moved since last year. The U.S. promise that went away was the Biden administration’s target of 61% to 66% below 2005 levels by 2035.
It isn’t news this year either. Last year’s report already had it: “the upcoming withdrawal of the US from the Paris Agreement will cancel another 0.1°C,” UNEP wrote in November 2025.
The report itself names two causes for this year’s higher number:
“This is a worse outcome than expected last year, as a result of the formal withdrawal of the United States of America from the Paris Agreement and revised estimates of historical emissions,” the report said.
The lead author gives the whole tenth to the first one.
Then AP goes to outside voices.
“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,” said Mohamed Adow, director of Power Shift Africa, a climate organization. “An extra tenth of a degree might sound insignificant, but in climate terms it is enormous. It means more dangerous heat waves, more destructive floods, more failed harvests and more lives lost. For vulnerable communities in Africa, already living on the front lines of the climate crisis, every fraction of a degree matters. These are not abstract numbers. They are human lives.”
It does sound insignificant. The number came from the report’s lead author.
Hare said that extra one-tenth of a degree pushes an additional 140 million people “into dangerously hot conditions” and increases the odds of the collapse of the Amazon rain forest or ice sheets in Greenland and Antarctica. It also would cost the world and shave about $1.2 trillion from the global economy, said University of Pennsylvania climate scientist Michael Mann.
The 140 million comes from a 2023 paper in Nature Sustainability led by Tim Lenton of the University of Exeter. In Exeter’s words, “for every 0.1°C of warming above present levels, about 140 million more people will be exposed to dangerous heat.” In that paper, “dangerous heat” means living somewhere with an average temperature of 29°C or higher. That number was worked out for warming above today’s levels. Hare applies it to a tenth added on top of 2.6°C in the year 2100. AP gives no source for Mann’s $1.2 trillion, and I couldn’t find one.
Milloy says a tenth of a degree isn’t even measurable. NASA disagrees, on paper. GISS puts the 95% uncertainty of its global annual mean at about 0.05°C for the last 50 years. That figure comes from statistics across thousands of stations and ships. It is not what the instruments can resolve. Pat Frank, in a 2023 paper in Sensors, put the lower limit from thermometer resolution alone at ±0.25°C (2σ) for the record before 1981, before adding the systematic errors of the sensors in the field. By that measure, a tenth of a degree is lost in the noise of any single year.
The tenth in this story will never face a thermometer anyway. It is the gap between two model projections of 2100, one with an American promise and one without. Only one of those worlds will happen, so there will never be anything to measure it against.
How much of the increase came from the revised historical emissions, if the United States accounts for the whole tenth?
And where does Mann’s claim about the $1.2 trillion come from? I couldn’t find it.
