Current global commitments to cut greenhouse gas emissions fall far short of Paris Agreement goals, putting the world on track for 2.6 degrees Celsius of warming this century, the U.N. warned Wednesday.
The report by the U.N. Environment Programme (UNEP) highlights the gap between rhetoric and action on global warming and the challenge facing political leaders at November's COP31 climate summit.
Even if countries deliver their latest climate pledges in full, global temperatures could still rise 2.6 C above preindustrial levels by 2100, the annual Emissions Gap Report said.
That would blow past the historic goal agreed to in Paris: keeping warming well below 2 C while striving for a safer 1.5 C. Any chance of meeting the 1.5 C target had been "lost" due to decades of insufficient climate action, the report said.
"The world can no longer avoid overshooting the 1.5-C limit, and the consequences are already devastating," U.N. Secretary-General Antonio Guterres said in a statement launching the closely watched report.
"Deadly floods, brutal heatwaves, raging wildfires, lost lives, crippled economies, deepening inequalities, and those least responsible are suffering first and worst," he added.
Overall, global greenhouse gas emissions in 2025 were broadly on par with record levels in 2024. The difference between the two years was insignificant, the report said.
Carbon emissions from burning coal, oil and gas – the main driver of climate change – rose slightly in 2025 compared to the previous year.
Guterres said deep, immediate cuts were needed to protect humanity from worsening impacts, but instead, emissions remain at record levels, and national climate plans and current policies fall dangerously short.
Sticking with current policies would result in warming hitting 2.8 C, the report said.
No country immune
Scientists warn that every additional fraction of a degree Celsius above 1.5 C increases extreme weather events and the likelihood of irreversible changes to the planet, from dying coral reefs to melting permafrost.
The world has already warmed roughly 1.4 C relative to preindustrial times, and crossing 1.5 C is expected in a matter of years.
The G-20 accounts for three-fourths of global emissions, but Guterres said "all countries, especially the big emitters, must do more" to stop heating the planet.
This latest UNEP warming outlook is worse than last year's due to the formal withdrawal of the U.S. from the Paris accord and upward revisions of historical emissions, report co-author Anne Olhoff said.
Emissions growth slowed among the G-20, but the U.S. was a "major exception," the report added.
Among the world's top-six emitters, preliminary data for 2025 showed emissions increases in the U.S., Indonesia and China and decreases in India, Russia and the European Union.
But in terms of magnitude, the U.S. increase of 133 megatons of carbon dioxide equivalent "far exceeded" that of any other country, driven by higher electricity demand and a rebound of coal power generation.
The next-largest increase was recorded in Turkey, which is hosting the U.N. climate summit in Antalya from Nov. 9-20.
The U.S. is the world's second-largest polluter, behind China. President Donald Trump has called climate change a hoax and rolled back clean energy policies while boosting fossil fuel production.
UNEP Executive Secretary Inger Andersen told reporters that no country was shielded from climate change, and impacts were being felt "on every nation on the planet, including the U.S."
'Historic failure'
The report details a scenario with a 50% chance of bringing global warming back down to 1.5 C by 2100.
To get there, warming must peak around 1.8 C by 2050, and vast amounts of CO2 would have to be removed from the atmosphere to bring temperatures down further.
But this scenario assumes immediate emissions cuts of 6% annually until 2035 – nowhere near current projections.
"The main takeaway is simple – governments need to get on with enacting policies that cut fossil fuel use as soon as possible," Bill Hare, CEO of global policy institute Climate Analytics, said.
Some climate-vulnerable developing nations have accused bigger emitters of abandoning the Paris goals, and a showdown over the 1.5 C target is expected at COP31.
"This is a historic failure of political leadership. The science has been clear for decades, but governments have chosen delay over action. The consequences will be measured in lives lost, not just degrees of warming," Mohamed Adow, director of Kenya-based think tank Power Shift Africa, said.
Guterres agreed there was a climate "leadership gap" but said overshooting 1.5 C "is not surrender."