Ocean temperatures hit record amid El Niño
Ocean temperatures hit 21.1°C, the highest on record, per Copernicus data. Human-driven warming and El Niño are blamed.
The world’s oceans have just set a new temperature record. Copernicus, the European climate-change service, reported an average surface temperature of 21.1 °C (70 °F) outside the polar regions on Saturday. This exceeds the 21.09 °C recorded in March 2024 and is far above the seasonal average for this time of year. The data come from measurements taken 10 m (32 ft 10 in) below the surface, combining buoys, ships and satellite observations to produce a global estimate.
| Month | Average Surface Temperature (°C) |
|---|---|
| March 2024 | 21.09 |
| Saturday (record) | 21.1 |
Dr Samantha Burgess, deputy director of Copernicus, said the record is “another clear signal of an ocean under growing stress.” She added that El Niño is adding heat on top of decades of human-driven warming.
El Niño’s Growing Influence
Scientists note that the timing of the record is significant. Global sea temperatures normally peak in March or April, coinciding with the end of summer in the southern hemisphere, which covers more ocean surface than the north. The record was set before El Niño reaches its expected peak, which is projected to strengthen until Christmas and could be the strongest in centuries.
Dr Jeremy Grist, senior research fellow at the National Oceanography Centre in Southampton, warned that the current record is an early indicator of El Niño’s strength. He suggested that, “All things being equal we might expect the ocean temperature record to be broken again in March or April 2027.”
The warming is not limited to the Pacific. Around the UK and Europe, the western English Channel has experienced almost continuous marine heatwave conditions for more than three years, peaking at 7 °C above normal in July, according to Prof Tim Smyth, director of science at Plymouth Marine Laboratory. “This is unprecedented,” he said.
Implications for Weather and Marine Life
Warmer seas can fuel more extreme weather. They provide storms with extra moisture and energy, and can intensify heatwaves on land in some coastal regions by reducing the cooling effect of sea breezes. The oceans also expand as they warm, raising sea levels and increasing the risk of coastal flooding. Intense ocean heat can devastate marine habitats such as coral reefs.
Burgess added that the increasing frequency of marine heatwaves is “putting increasing pressure on marine ecosystems and the communities that depend on them.” The oceans absorb more than 90 % of the excess heat trapped by greenhouse-gas emissions, mainly from burning fossil fuels.
The record-setting temperature aligns with the latest stats for global sea temperatures, and the trend mirrors the standings of ocean heat anomalies worldwide.
The western English Channel has seen almost continuous marine heatwave conditions for more than three years, peaking at 7 °C above normal in July, according to Prof Tim Smyth.
