The United Nations Environment Programme has said the goal of keeping global warming within 1.5°C, the central temperature limit in the 2015 Paris Agreement, is no longer attainable. Its report, released on 02 September 2026, says Earth will exceed the threshold before the end of the decade.
The report, titled Limiting Overshoot, sets out a shift in emphasis for governments. Rather than seeking to prevent temperatures from moving above 1.5°C, UNEP says countries must seek to manage an expected period above that level and limit its length and severity.
Under current policies, median projected global warming reaches around 2.6°C by 2100, the report said. UNEP said the strongest outcome now available would be warming of about 1.8°C above pre-industrial levels this century.
Current warming has reached approximately 1.4°C relative to 1850-1900. Global temperatures exceeded 1.5°C above pre-industrial levels in 2024 for the first time. Experts have yet to determine that the Paris Agreement target has been breached, however, because the benchmark is measured over a 20-year average rather than a single year.
Inger Andersen, UNEP’s executive director, said: “Even though global warming is set to cross 1.5°C above pre-industrial levels, likely within the next few years, the goal remains limiting warming to this level. However, the goal must now be approached from above while the world adapts to intensifying climate impacts”.
UNEP described the required course as an “overshoot, peak, and decline” pathway. It said governments should focus on reducing the time temperatures spend above 1.5°C and on containing the level reached during that period.
The report said a return to below 1.5°C remained possible, though highly uncertain. It would require rapid cuts in emissions and measures to remove carbon dioxide already in the atmosphere. Planting new forests was among the carbon dioxide removal measures UNEP said would be critical to controlling temperature rises.
The feasibility of scaling up carbon removal remains uncertain. It is also unclear whether governments will adopt binding targets for managing overshoot or whether national pledges will be carried out. The timing of a formal breach of the 1.5°C threshold is also unknown because it depends on the 20-year average used to assess the target.
UNEP warned that every year of delay, and every fraction of a degree above 1.5°C, would increase risks and make a later return harder. Some losses could be irreversible even if temperatures subsequently fall, it said.
Higher temperatures are expected to bring more extreme weather and greater pressure on ecosystems, glaciers and low-lying coastal cities. UNEP said the likely harms include worsening heat waves, greater sea-level rise, extensive flooding and the possible collapse of coral reefs.
The report comes after the U.S. officially pulled out of the Paris Agreement in January. The U.S. is the globe’s biggest historical greenhouse gas emitter. Governments agreed under the Paris Agreement to keep temperature rises within 1.5°C, and UNEP’s assessment now places greater weight on adaptation alongside efforts to cut emissions and lower temperatures after an overshoot.
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