Global Ocean Temperatures Hit Record High Amidst Strengthening El Niño
Average surface temperature outside polar regions reached 21.1C on Saturday, surpassing previous records as scientists warn of a potentially historic El Niño event.
Image: Eddie Pollard / AI
Carla Rooney
The planet's seas outside the polar regions reached an average surface temperature of 21.1C (70F) on Saturday.
Dr. Samantha Burgess of the European Union’s Copernicus Climate Change Service (C3S) produced the new data, which covers oceans outside the polar regions.
This data, stretching back to 1979, relies on sea temperatures 10m (32ft 10in) below the surface, utilizing measurements from buoys, ships, and satellites.
Oceans absorb over 90% of the excess heat trapped by humanity's greenhouse gas emissions. This long-term trend now faces exacerbation by natural climate cycles.
El Niño, a naturally occurring climate cycle, brings unusually warm waters to the surface of the eastern and central tropical Pacific Ocean.
Experts confirm El Niño adds further heat to an ocean already warming over many decades due to human-caused climate change.
A growing Super El Niño develops in the tropical Pacific, driving a huge buildup of hot water stretching out towards Oceania.
Scientists expect El Niño to keep strengthening until Christmas time. Warnings indicate it is on course to be the strongest in centuries.
The warming in the Pacific could reach 3°C (5.4°F); some projections indicate an increase as high as 4°C (7.2°F).
This combination means average temperatures are likely to be much higher than they naturally would be, according to experts.
The number of marine heatwave days globally has more than tripled since the early 1990s.
The southern hemisphere contains more of the planet's ocean water than the northern hemisphere.
The world’s most recent La Niña event, the cooler phase of the El Niño Southern Oscillation, lasted from late 2020 to early 2023.
As the planet enters an El Niño phase, the powerful trade winds that normally blow hot water across the Pacific towards Australia reportedly weaken, or even reverse.
The UK experienced a dry July in 2026, the driest in 190 years, with drought conditions in England and Wales.
August 22 stands as the hottest August day for the world's oceans since records began, surpassing the previous record set in 2023.