The oceans reached near-record temperatures last month, in March, according to the European Copernicus Observatory, a sign of the likely return of the El Nino natural warming phenomenon, which would accentuate human-induced climate change, AFP and Agerpres note on Friday.
Copernicus' monthly bulletin, published on Friday, is a wake-up call: after the three hottest years ever recorded on Earth, the increasingly likely return of El Nino in the second half of the year is raising fears among climate experts that humanity is headed for new periods of extreme heat.
The average ocean surface temperature was 20.97 degrees Celsius in March (excluding polar regions), a tenth of a degree below the record set in March 2024. And the average continues to rise in April, according to Copernicus' real-time “dashboard”.
The last El Nino event, in 2023 and 2024, made these two years the warmest on record. This cyclical phenomenon corresponds to the periodic, large-scale warming of waters in one part of the Pacific Ocean, which has a domino effect on the global climate over several months.
Ocean temperatures “indicate a likely transition to El Nino conditions,” according to Copernicus.
The UN's World Meteorological Organization (WMO) has already estimated that a return is possible this year, while the opposite phenomenon, La Nina, associated with cooler temperatures, is fading. At the beginning of March, the WMO estimated at 40% the probability of the occurrence of El Nino until July.
Warming oceans cause water to expand, raising sea levels. This intensifies marine heat waves, which weaken coral reefs and exacerbate extreme weather events such as torrential rains and cyclones.
Taken together, on land and sea, March ranks fourth in terms of global surface temperatures, 1.48°C above values estimated in the pre-industrial period (1850-1900), before the massive burning of coal, oil and gas led to a lasting warming of the climate.
🌡️ Copernicus Climate Change Service reports March 2026 was the 4th-warmest globally (+1.48°C above pre-industrial).
🌍 Maps show strong contrasts: heat in the US & Arctic, colder zones in Canada & parts of Europe.
🔗 https://t.co/i5xtJ3EShu#CopernicusEU #ImageOfTheDay pic.twitter.com/8Ozp7ShHym
— Copernicus EU (@CopernicusEU) April 10, 2026
