World’s oceans at record high temperatures at an unusual time of year

The average sea-surface temperature has exceeded 21.1 degrees. It has not been this warm for as long as records have been kept.

The record was set on 21 August, according to the EU’s Copernicus Climate Change Service, whose data series outside the polar regions dates back to 1979. What stands out is that the temperature is so high despite the fact that global sea temperatures are usually at their highest in March. The temperature is marginally higher than the previous record set on 1 March 2024. A combination of climate change and a strengthening El Niño is to blame. Scientists are somewhat uncertain about historical sea temperatures, but studies suggest that it may last have been this warm 125,000 years ago. Marine heatwaves are taking a heavy toll on animals and plants. Warm water also expands, contributing to rising sea levels.