The World Meteorological Organization (WMO) said Earth’s energy imbalance reached its highest observed level in 2025, while preliminary readings suggest it may have risen again in 2026. The agency warned that a strengthening El Niño could heighten climate risks into 2027.
The 2025 measurement was the largest since WMO began monitoring the imbalance in 1960. Preliminary readings for January through July 2026 point to a possible new high, but the 2026 result is not final.
For the first nine months of 2026, the global mean surface temperature was 1.47°C above the 1850–1900 reference, with an uncertainty of ±0.13°C. That was close to the full-year averages for 2025, at 1.43°C, and 2023, at 1.46°C, but below 2024’s record of 1.55°C. WMO expects 2026 to rank among the four warmest years in its records.
El Niño had intensified since August. WMO expects it to reach record strength by December and continue into early 2027, while related risks could last well into 2027. The agency said the effect on global temperatures often peaks in the year after an El Niño develops, pointing to 2024 as the warmest year in its record. “This 2026/2027 El Niño is off the charts,” WMO Secretary-General Celeste Saulo said.
WMO links the imbalance to greenhouse gases that trap heat in the Earth system. The oceans have taken up about 90% of that excess heat, the agency said. El Niño shifts some ocean-stored warmth into the atmosphere; it does not add heat to the planet, but can raise the likelihood of extreme heat, drought and heavy rainfall.
WMO said those risks are particularly serious in food-insecure areas where farming depends on rainfall. Preliminary estimates cited by the agency linked European heat waves, drought and wildfires to more than 30,000 excess deaths. WMO also estimated that 146.5 million people in India were exposed to extreme heat during an April 2026 heat wave.
Preliminary ocean readings through July put 2026 on course for a 10th consecutive year of record ocean heat content. WMO also reported that global mean sea level reached a high in 2026, with June, July and August each setting new highs in the satellite record, which began in 1993. The agency plans to release its final State of the Global Climate 2026 report in March 2027.
