UNEP: Chance of Keeping Warming Below 1.5°C Without Overshoot Is Gone

The United Nations Environment Programme said Wednesday that the world has effectively lost the chance to keep global warming below 1.5 degrees Celsius without temporarily exceeding that threshold, marking a sharper warning in one of the most closely watched annual assessments of climate progress.

In its “Emissions Gap Report 2026: The Point of Return,” released Oct. 21, UNEP said “the chance of holding global warming to below 1.5°C above pre-industrial levels with no or limited overshoot is gone.” Even in the most optimistic pathway it modeled, global warming would still reach about 2.1 degrees this century.

The report underscores a central tension in the climate outlook: Emissions growth has slowed, but total emissions are still rising and remain at record highs. The International Energy Agency said global energy-related carbon dioxide emissions rose about 0.4% in 2025, the slowest growth in recent years, but still climbed to a record high of more than 38 gigatons. Separately, U.N. sustainable development indicators estimate total global greenhouse gas emissions reached a record 57.7 gigatons of carbon dioxide equivalent in 2024.

UNEP’s updated warming estimates show how far current action still falls short of the Paris Agreement goals. The agency said the world is on track for about 2.8 degrees of warming if current policies continue. If countries fully deliver the national climate plans they have formally submitted under the Paris accord, known as Nationally Determined Contributions, warming would be about 2.6 degrees. In UNEP’s most optimistic case, where countries meet those pledges and their additional net-zero targets, warming would still be about 2.1 degrees.

UNEP said the focus must now shift to limiting how far temperatures rise above 1.5 degrees, how long they stay there, and whether they can be brought back down by the end of the century.

To achieve what UNEP called its lowest-possible overshoot-and-return pathway, global greenhouse gas emissions would need to fall 18% by 2030, 45% by 2035 and 69% by 2040, all relative to 2025 levels. Even then, the report said, temperatures would still likely peak at roughly 1.7 to 1.8 degrees around midcentury before returning to 1.5 degrees or below by 2100, with about a 50% chance.

That pathway would also require the removal and permanent storage of roughly 320 gigatons of carbon dioxide over the century, a scale UNEP said faces major technological, social and economic obstacles.

The Emissions Gap Report is UNEP’s annual assessment of the difference between where global emissions are heading under current policies and pledges and where they would need to go to meet the Paris temperature goals. In climate policy, “overshoot” means global temperatures rise above 1.5 degrees for a period before being lowered later through much steeper emissions cuts and carbon removal. The significance of this year’s report is that UNEP is no longer presenting 1.5 degrees without overshoot as a plausible outcome.

UNEP said this year’s projections were worse than last year’s partly because of “the withdrawal of the United States of America from the Paris Agreement and revised estimates of historical emissions.” The U.N. Treaty Collection shows the United States submitted notice of withdrawal on Jan. 27, 2025, and the withdrawal took effect on Jan. 27, 2026.

The report said recent renewable energy growth and climate policies have reduced emissions in some countries and sectors, but overall global indicators for absolute greenhouse gas emissions are still “heading in the wrong direction.”

Inger Andersen, executive director of UNEP, said in the agency’s press release: “Every additional fraction of a degree and additional year of warming above 1.5°C increases climate impacts and risks, such as the deadly floods, heatwaves and wildfires that have plagued many nations this year. … We have a wealth of success stories showing that emissions can be cut quickly. It is now up to nations to urgently put in place policies that spark fast, deep and sustained emissions reductions…”