Global El Niño climate impacts

How the story developed

The current climate pattern began intensifying in September. On September 12, the National Oceanic and Atmospheric Administration forecast a 75% chance of a historically strong El Niño peaking between October and December, projecting sea surface temperatures in the central Pacific could exceed a 2.5 degrees Celsius anomaly. Only three previous events in modern history—1982, 1997, and 2015—had reached this thermal threshold. By September 14, severe drought driven by the phenomenon had severely dried out highly flammable peatlands in Indonesia. The burning of these drained, carbon-rich peatlands released 19.7 million metric tons of carbon dioxide in the first week of September, surpassing Russia to become the highest globally for that period. Air quality in parts of West Kalimantan reached hazardous levels above 390. On September 15, data confirmed sea surface temperature anomalies in the equatorial Pacific breached the 2 degrees Celsius threshold, officially elevating the pattern to a super El Niño event and suppressing Atlantic hurricanes.

The ocean heat continued to escalate rapidly. On September 24, the sea surface temperature anomaly reached 3.05 degrees Celsius, breaking the previous 2015 record of 3.02 degrees Celsius months before the typical winter peak. The following day, the Climate Impact Lab forecast that extreme heat driven by the event will claim 451,000 additional lives worldwide between June and February 2027, with excess heat already causing an estimated 200,000 deaths since June. The fatalities are heavily concentrated in the Global South, with the African Sahel and Southeast Asia facing the steepest tolls, and Nigeria forecast to suffer over 31,000 casualties. Researchers released the data early to help governments deploy targeted interventions like cooling centers and heat warnings.

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Economic and infrastructure impacts also came into focus. On September 26, the United Nations Economic Commission for Latin America and the Caribbean projected that a high-intensity El Niño could reduce Latin America's gross domestic product by at least 2% over three years and push an additional 4.8 million people into poverty by 2030. The National Oceanic and Atmospheric Administration projected a greater than 90% probability of a very high-intensity El Niño in late 2026. Aging hydroelectric grids in the region face severe strain from projected rainfall deficits of up to 60%, prompting calls for governments to adopt anticipatory climate risk management and diversify energy sources.

The humanitarian crisis expanded on September 27 when the World Health Organization declared the anticipated health impacts of El Niño in Africa a Grade 3 emergency, its highest crisis classification. The agency warned that 18 African countries face high risks of severe flooding, drought, and disease outbreaks through 2027. Eastern and central Africa face increased threats of cholera, malaria, and dengue, while southern Africa is projected to experience severe drought, worsening existing food insecurity and malnutrition. By October 10, the World Meteorological Organization forecast the El Niño will reach a record 3.7 degrees Celsius anomaly in the central Pacific by December, significantly exceeding the previous modern record of 2.6 degrees Celsius set during the 2015–2016 event. The extreme ocean heat is expected to drive severe droughts in India and Central America while causing heavy flooding in parts of Africa and the United States.

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What to watch

• The El Niño sea surface temperature anomaly is forecast to peak in November or December, potentially approaching an unprecedented 4.0 degrees Celsius.
• The World Health Organization is urgently seeking $2.2 million to fund immediate surveillance, emergency supplies, and rapid-response deployments in Africa.
• The compounding effect of El Niño and global heating is expected to make 2027 the hottest year on record.
• The climate event is expected to persist through February 2027.