El Niño drives record Pacific sea temperatures, BOM says

Average weekly sea-surface temperatures in the central Pacific have reached their highest level on record, Australia’s Bureau of Meteorology (BOM) said in its latest update, as El Niño continues to strengthen weeks before an expected peak in December. Several key measures of the Pacific pattern are now in record territory.

How strong is this El Niño?

The BOM figures come from the equatorial Pacific region used to monitor El Niño. Scientists declared a new record for daily sea-surface temperatures in the central-eastern Pacific in September, exceeding the previous record set during the very strong El Niño of 2015. Temperatures above 30C have been recorded for the first time in parts of the tropical Pacific, along with record sea-surface temperature anomalies and exceptional subsurface warmth.

Australian and US forecasters now use a Relative Ocean El Niño Index (RONI) to remove the background warming caused by human-induced climate change, which is starting to mask the strength of the natural warming during El Niño. On that measure, the BOM’s average weekly data, which goes back to 2008, exceeds levels recorded during the record-breaking December of 2015. The UN has warned that El Niño could be the strongest in more than 70 years.

“We are currently witnessing an El Niño event that is unprecedented in the historical record,” Dr Zeke Hausfather, a climate scientist at Berkeley Earth, told the BBC.

Is the warmth spreading beyond the tropics?

Ocean warmth now extends well beyond the tropical region normally used to monitor El Niño. Comparisons with the major events of 1972-73, 1982-83, 1997-98 and 2015-16 show much more widespread warmth across the Pacific and into the Gulf of Mexico. Part of that reflects the long-term warming of the oceans, though scientists say it is not the whole story. “The strength of El Niño this year is spilling out of the traditional El Niño region,” Dr Hausfather said.

What does it mean for global temperatures?

El Niño releases additional heat from the oceans into the atmosphere, and global temperatures during El Niño years are typically higher than during neutral years. Combined with human-driven climate change, that extra heat is expected to help make 2026 one of the warmest years on record, with unusually high global temperatures likely to continue into 2027.

What happened during previous super El Niños?

During the 1997-98 event, severe drought across south-east Asia contributed to extensive peat and forest fires, while parts of East Africa experienced devastating floods; the event also helped make 1998 the warmest year on record at the time. In 2015-16, drought and wildfire activity returned to parts of south-east Asia, and southern Africa had one of its worst droughts in decades, triggering a major humanitarian crisis. Strong El Niño events typically suppress Atlantic hurricanes while boosting activity across parts of the Pacific, a pattern also observed during 2026. In Brazil, separate figures showed a record drop in Amazon deforestation before the runoff.

What do forecasters expect next?

The World Meteorological Organization says there is currently no evidence that climate change is making El Niño events stronger or more frequent, though it remains an active area of research. The WMO reports drought and flood-related disruption in several regions, with growing concern over food security in parts of East Africa and the Asia-Pacific. Forecasts from the European Centre for Medium Range Weather Forecasts and the US National Oceanic and Atmospheric Administration indicate El Niño is likely to peak in December. Dr Hausfather called the latest projections “astonishing” and said they are likely to set new records “by a remarkable amount”.

Frequently asked questions

How strong is the current El Niño?

Australia’s Bureau of Meteorology says average weekly sea-surface temperatures in the central Pacific are the highest on record, and temperatures above 30C were recorded for the first time in parts of the tropical Pacific.

When will El Niño peak?

Forecasts from the European Centre for Medium Range Weather Forecasts and the US National Oceanic and Atmospheric Administration indicate El Niño is likely to peak in December.

Does climate change make El Niño stronger?

The World Meteorological Organization says there is currently no evidence that climate change is making El Niño events stronger or more frequent, though it remains an active area of scientific research.

Which regions are already affected?

The World Meteorological Organization says drought and flood-related disruption is already being reported in several regions, with growing concern over food security in parts of East Africa and the Asia-Pacific.

With reporting from BBC News.

Stock image, not from the events described. Ocean Wave — Tim Sullivan / Wikimedia Commons (CC0 1.0)