Ocean temperatures reached near-record highs in March, according to the Copernicus Climate Change Service. This signals a likely transition toward El Niño conditions, which can amplify heat extremes on an already warming planet.
Average sea surface temperatures in March were 20.97°C, the second-highest value ever recorded for the month and the hottest since 2024, a year marked by extreme global heat.
Meteorological agencies had predicted the return of El Niño this year, a natural climate cycle that warms Pacific waters and can lead to higher global temperatures and extreme weather events. The World Meteorological Organization indicated a cooling La Niña cycle would give way to neutral conditions before swinging into El Niño later this year.
Scientists emphasize that while El Niño and La Niña are natural cycles causing short-term temperature swings, human-driven climate change is the long-term driver of rising global temperatures and worsening extreme weather.
Oceans absorb a significant portion of excess heat from carbon emissions, playing a crucial role in regulating global climate. Hotter seas fuel stronger storms, cause coral bleaching, and contribute to sea-level rise.
Copernicus also reported March as the fourth-hottest March on record globally, with average temperatures 1.48°C above pre-industrial benchmarks. Record-breaking temperatures were observed across much of Europe, with the most pronounced extremes in the United States. The Arctic and parts of Russia and Antarctica also experienced above-average temperatures. March saw the lowest Arctic sea ice cover on record for the month.
"Each figure is striking on its own - together, they paint a picture of a climate system under sustained and accelerating pressure," stated Copernicus director Carlo Buontempo.