UN Report Finds US Is the Only Major Economy With Rising Climate Pollution

On 21 October, the United Nations Environment Programme published the seventeenth edition of its annual Emissions Gap Report, this one called The Point of Return. One finding separates the United States from every other major economy in the Group of Twenty: American greenhouse gas emissions rose by 133 million metric tons of carbon dioxide equivalent in 2025, an increase the report says far exceeded that of any other country. Among the 124 countries whose emissions went up last year, the combined rise was 189 million tons. Seventy per cent of that increase came from the United States alone.

Globally, greenhouse gas emissions reached 58.4 gigatonnes of carbon dioxide equivalent in 2025, statistically unchanged from the record set in 2024. Carbon dioxide from burning coal, oil and gas for power rose; a fall in land-use emissions, partly because wildfires were less severe than in 2024, offset that rise. The authors warn against reading the flat number as a peak. It is too soon, they write, to conclude that global emissions have plateaued.

The report's charts are not abstract for the engineer I keep thinking about, a grid reliability planner in the Ohio Valley who spent 2025 watching demand climb while gas prices rose. Her job is to keep the lights on, and the data told her to run the coal units harder. She didn't write the policy that kept those plants open. She just had to balance the load.

The window on 1.5°C has shut

The chance to hold warming to the Paris Agreement's 1.5°C target with no or limited overshoot has been lost, the report concludes. Decades of insufficient emission cuts make an overshoot imminent and unavoidable. The question the authors now ask is narrower: how high the overshoot peaks and how quickly temperatures can be brought back down.

Under current policies the world is heading for about 2.8°C of warming this century, with temperatures still climbing after that. Full delivery of every national climate plan would still leave 2.6°C. The most optimistic scenario, all pledges plus every net-zero target excluding the United States, stops at 2.1°C. Each figure is worse than last year's projection, a shift the report attributes to the formal US withdrawal from the Paris Agreement and to revised estimates of historical emissions.

The lowest possible 1.5°C overshoot pathway would peak at 1.7 to 1.8°C around mid-century and offer about a 50 per cent chance of returning to 1.5°C by 2100. "We are now saying this window has closed, but we can open it again," UNEP Executive Director Inger Andersen told reporters. Secretary-General Antonío Guterres put the stakes plainly: "Overshoot is not surrender. We can still keep it as small and as short as possible."

What a cold winter and a data-centre boom did to US emissions

Independent estimates from the Rhodium Group, published in January, had already flagged the reversal. US greenhouse gas emissions rose 2.4 per cent in 2025, the first increase after two years of decline, and they grew faster than the economy's projected 1.9 per cent output growth. That broke a three-year stretch in which the American economy expanded while emissions fell.

Two sectors drove the increase. Direct emissions from buildings rose 6.8 per cent as a colder winter pushed up space heating. Power-sector emissions rose 3.8 per cent, helped by a 13 per cent jump in coal generation after benchmark Henry Hub natural gas prices rose 58 per cent year on year. Demand grew everywhere at once: data centres and cryptocurrency mining operations, Rhodium's sector-by-sector breakdown shows, were concentrated in Texas, the Mid-Atlantic and the Ohio Valley, where older coal units still anchor the grid. The International Energy Agency attributes roughly half of 2025's increase in US electricity consumption to data centres, which now use around six per cent of the country's electricity.

Progress did not stop. Solar generation rose 34 per cent and surpassed hydro for the first time; zero-carbon sources supplied 42 per cent of US electricity. Transport, the largest source of American emissions, was essentially flat despite record travel, because hybrids and electric vehicles kept gaining ground. Even with the rise, US emissions remained 18 per cent below 2005 levels.

Rhodium was careful about what the 2025 number does and does not say. Federal policy rollbacks had not been in place long enough to move the 2025 figures meaningfully, the analysts wrote, but they could slow reductions for years to come. The firm's 2035 outlook under current policy has already weakened: a projected 38 to 56 per cent cut below 2005 levels before the administration changed is now a projected 26 to 35 per cent cut.

Photo by Documerica on Unsplash

Policy, not weather, is the longer tail

The 2025 increase had natural causes, a cold winter chief among them. What worries the report's authors is what comes next. The US government has formally disavowed the report, stating it "does not endorse or agree with its analysis or conclusions, and has not provided comments to this report." The State Department did not answer questions from NPR.

Since taking office, the administration has ordered coal-fired power plants to stay open longer than planned, rolled back vehicle fuel-efficiency standards, ended tax credits for solar and wind projects, and reversed the Environmental Protection Agency's position that greenhouse gases endanger human health and welfare. The United States left the Paris Agreement for the second time, effective 27 January 2026, and has said it will not take part in UN climate talks. UNEP's press release summarises the full findings.

Lead author Anne Olhoff, who directs the UNEP Copenhagen Climate Centre, estimates the American policy reversal will likely add about one-tenth of a degree Celsius to end-of-century warming all by itself. That is the gap between commitments and budgets made concrete: a single tenth of a degree that raises heatwave exposure, storm damage and insurance losses in every country, including the United States. Mohamed Adow, director of Power Shift Africa, put the consequence plainly: "It has real consequences for the planet and for millions of people around the world."

The rest of the G20 shows emissions can still fall

Standing next to the US figure, the rest of the G20 looks different. Collective emissions growth among the group slowed in 2025. The European Union cut emissions, partly because it invested in efficient appliances and renewables after Russia's invasion of Ukraine; among the top six emitters, India, Russia and the European Union posted declines while Indonesia, China and the United States rose. Turkey, which hosts this year's climate summit, was second on the increase list at 24.4 million tons, a fraction of the American rise.

Some of this progress predates the report's 2026 gloom. Since the Paris Agreement was signed, global renewable electricity capacity has grown three times faster than anticipated, and solar deployment seven times faster. In 2025 the world generated more electricity from renewables than from coal for the first time. "Several G20 members have shown sustained emissions reduction," Andersen noted, even amid the energy-security scramble caused by the wars in Ukraine and Iran. Carbon Brief's analysis walks through the scenario design behind these projections.

What the lowest-overshoot pathway actually requires

The report is specific about the arithmetic. To stay on the lowest possible overshoot path, global emissions must fall 18 per cent by 2030, 45 per cent by 2035 and 69 per cent by 2040, all measured against 2025. Those are much deeper cuts than the current national plans would deliver: full implementation of every nationally determined contribution the UN has received from 167 countries, covering 83 per cent of global emissions, would trim emissions by only 5 to 8 per cent by 2030 and 11 to 15 per cent by 2035. That trajectory implies average annual reductions of about 5.7 per cent from 2025 to 2035, steeper than the old IPCC pathways, which assumed about 5 per cent a year starting years ago.

The fuel shifts behind those numbers are harder than the percentage headlines suggest:

• Coal's share of total energy supply would need to fall at least 55 per cent by 2035 and 75 per cent by 2040 from 2025 levels.
• Oil's share would need to fall 15 per cent by 2035 and 30 per cent by 2040.
• Gas burned for power and heating would need to drop 5 per cent by 2035 and 35 per cent by 2040.
• Methane emissions would need to come down 25 per cent by 2035.

Then there is the part no grid operator can currently schedule: roughly 320 gigatonnes of carbon dioxide would need to be removed from the atmosphere and permanently stored over the century, equivalent to about eight years of 2024's global emissions. The report calls the technological and socioeconomic barriers to that scale huge. The warming the world already has is not waiting for the engineering to catch up. Wildfire smoke from Canadian blazes has drifted across the US border in recent years, as covered in this earlier report on cross-border air-quality alerts.

Photo by Katja Rooke on Unsplash

What COP31 can measure, and what it cannot

The report lands nineteen days before delegates open COP31 in Antalya, Turkey, on 9 November. The United States will not be at the table. That absence matters beyond the arithmetic, because the country's formal exit changed how the UN calculates the gap: the Biden-era commitment to cut a gigaton of emissions by 2030 has been omitted from the projections. A gigaton is roughly a year of emissions from the entire American vehicle fleet.

Scientists outside the process read the consequences the way the report does. Australian climate scientist Bill Hare, chief executive of Climate Analytics, called the American posture "hell-for-leather trying to block renewables while actively promoting and subsidizing dirty coal." He added: "It is looking at the fire, denying there is a fire, and then pouring more petrol on it." Johan Rockström, director of the Potsdam Institute for Climate Impact Research, said the US effect is probably larger than the model shows, because when the largest historical emitter steps back, other governments ease off as well.

Andersen's response is blunt. "We must pull out all the stops to minimize peak warming and return to 1.5°C by the end of the century," she said. "This is possible." The engineer in the Ohio Valley would probably say the same about her grid: possible is a scheduling problem, not a slogan. What gets measured next, the G20's per-capita emissions, coal generation, data-centre load and the 18 per cent benchmark by 2030, will reveal whether the commitments change or the budgets do.