An Arithmetic Gap Between Pledges and Trajectory

The report published on October 21, 2026 is darker than last year's, which projected 2.3 to 2.5 °C. Under current policies, warming could reach 2.8 °C by 2100. National contributions would deliver only a 5 to 8% emissions cut by 2030 and 11 to 15% by 2035, compared with 2025.

The lowest-warming pathway would require -18% in 2030, -45% in 2035 and -69% in 2040. That implies a pace of 5.7% per year over 2025-2035, above the 5% of earlier IPCC scenarios. The later the cut, the more brutal it must be afterwards.

The American Factor

Among the six largest emitters, the United States is the only one posting a marked increase between 2024 and 2025. Its emissions rose by 133 million tonnes of CO2 equivalent, roughly 70% of the 189 million tonnes added across 124 countries. The driver is rising electricity demand, coupled with a coal rebound.

Withdrawal from the Paris Agreement would by itself add about 0.1 °C by the end of the century. Climatologist Michael Mann values that tenth of a degree at $1.2 trillion for the global economy. Johan Rockström warns the impact could be heavier if other countries slackened their effort in response.

What Has Already Worked

The picture is not uniformly bleak. Global renewable capacity has grown three times faster than anticipated since the Paris Agreement, and solar photovoltaic capacity has increased sevenfold. More than 220 public policy assessments show average cuts of 9% in the power sector, and 5 to 13% with carbon taxes and allowance markets. Global emissions also stayed broadly flat between 2024 and 2025, mainly thanks to lower land-use emissions. That could mark a plateau, but nothing guarantees it.

Limiting the Overshoot Rather Than Avoiding It

The "minimal overshoot" scenario would cap the peak at 1.7-1.8 °C around mid-century, with a return to 1.5 °C by 2100 and roughly a 50% chance of success. It requires extracting and permanently storing some 320 gigatonnes of CO2, equal to eight years of emissions at 2024 levels. The technological and economic burden is considerable.

The Limits of the Analysis

These projections rest on assumptions about future policies. The economic impact of the US withdrawal is an individual estimate. The data in the file do not allow these trends to be linked to recent extreme weather episodes, such as the orange alerts in China, nor to measure their effect on energy indicators.

Weeks before COP31 in Antalya (November 9-20, 2026), the finding is clear. Current pledges are not enough. The scale and duration of the 1.5 °C overshoot now depend on how fast proven policies are scaled up.

This article was written with the assistance of artificial intelligence and verified by our editorial team.