Global average temperatures are expected to remain “at record or near-record levels” over the period 2026-2030, with a 75% probability that the average over these five years will exceed pre-industrial levels by more than 1.5°C, the UN warned on Thursday May 28.
The years 2015 to 2025 are the 11 hottest years on record, the World Meteorological Organization (WMO) indicated in March, and the trend is expected to continue according to a new report from this UN agency.
According to this WMO bulletin on global climate forecasts, compiled by the United Kingdom Meteorological Service, it is 86% “likely” that a year between 2026 and 2030 will break the record for the hottest year on record, currently held by 2024.
“An El Niño event is forecast for late 2026, which increases the chances that the following year, 2027, will be the next record year,” said Leon Hermanson, the lead author of the bulletin, which synthesizes forecasts provided by 13 different institutes.
Five-year average temperature forecasts in the central tropical Pacific indicate, according to the WMO, “a trend towards El Niño conditions”, particularly in 2027 and 2028.
El Niño is characterized by an increase in surface temperatures in the central and eastern equatorial Pacific. It usually occurs every two to seven years and lasts about nine to twelve months. The last El Niño episode, in 2023 and 2024, made these years the two hottest on record. The cyclical phenomenon affects the global climate through a domino effect for several months.
“Temporary overruns”
According to the report, published while part of Europe has been experiencing an exceptional heat wave for the month of May for several days, global temperature averages are expected to remain very high over the next five years, close to their historic highs.
According to the WMO, between 2026 and 2030, average annual surface temperatures on the globe will overall exceed the average of pre-industrial levels (1850-1900) by 1.3°C to 1.9°C. And it is “very likely” (91%) that the average global surface temperature will temporarily exceed 1850-1900 average levels by more than 1.5°C for at least one year between 2026 and 2030. This threshold was also temporarily exceeded in 2024, when the average global surface temperature was about 1.55°C higher than pre-industrial values.
According to the bulletin, however, it is “extremely unlikely” (less than 1% probability) that the average temperature on the surface of the globe will exceed the average of the period 1850-1900 by more than 2°C in any of the next five years.
The WMO recalls that the thresholds of 1.5°C and 2.0°C contained in the Paris Agreement refer to “long-term warming maintained over a prolonged period, generally assessed over 20 years”. The fact that the global average annual temperature exceeds these thresholds in some years does not mean that the long-term temperature goals of the Paris Agreement are out of reach, she explains, adding that temporary exceedances are expected to occur more and more frequently as the global warming trend “moves closer to these thresholds.”
Forecasts also show that warming in the Arctic is expected to continue to significantly exceed the trend observed on a global scale. Over the next five prolonged winters in the Northern Hemisphere (November-March), the temperature in the Arctic is expected to be 2.8°C higher than normal for the period 1991-2020.
According to forecasts for the period from March 2026 to March 2035, the concentration of Arctic sea ice is expected to decrease in the Barents, Bering and Okhotsk seas. Additionally, precipitation will be above average at high latitudes in the Northern Hemisphere over the next five prolonged winters (November-March).
