El Niño Reaches Unprecedented Strength Weeks Before Expected Peak
Sea-surface temperatures in the central Pacific have broken records set during the 2015 El Niño, with warmth spreading beyond traditional monitoring regions. The event is expected to contribute to 2026 being one of the warmest years on record.
El Niño has continued to strengthen to what some scientists are calling unprecedented levels, weeks before its expected peak in December. Australia's Bureau of Meteorology (BOM) reported that average weekly sea-surface temperatures in the central Pacific have reached their highest level on record.
In September, scientists declared a new record for daily sea surface temperatures in the central-eastern Pacific, exceeding the previous mark set during the 2015 El Niño. For the first time, temperatures above 30C have been recorded in parts of the tropical Pacific. Dr Zeke Hausfather, a climate scientist at Berkeley Earth, stated that the current El Niño event is unprecedented in the historical record.
To better compare current conditions with past events, Australian and US official forecasters are using a Relative Ocean El Niño Index (RONI), which removes additional warming signals from human-induced climate change. BOM's RONI data, available from 2008 onward, shows that average weekly readings now exceed levels seen during the record-breaking December of 2015.
The unusual warmth across the Pacific extends well beyond the tropical region normally used to monitor El Niño, spreading into the Gulf of Mexico. Despite this, the World Meteorological Organization (WMO) states there is currently no evidence that climate change is making El Niño events stronger or more frequent.
El Niño releases additional heat from the oceans into the atmosphere. Combined with human-driven climate change, this is expected to make 2026 one of the warmest years on record, with unusually high global temperatures continuing into 2027.
Historically, strong El Niño events have brought severe weather impacts. During the 1997-98 El Niño, severe drought across South-East Asia contributed to extensive peat and forest fires, while parts of East Africa experienced devastating floods. A similar pattern of drought in South-East Asia and flooding in East Africa developed during the 2015-16 El Niño. Current forecasts indicate risks of drought in South-East Asia and Southern Africa, flooding in East Africa, and altered tropical cyclone patterns. Strong El Niño events typically suppress Atlantic hurricanes but can increase tropical cyclone activity in other regions.