Oceans set June heat record as El Niño threatens more highs
EU scientists said June sea surface temperatures hit a record 21.0C, with marine heatwaves affecting much of the global ocean.
By James Whitfield · Staff Writer
2 min read
The world’s oceans recorded their hottest June on record, and scientists say more highs could follow as El Niño builds alongside human-driven warming. The finding matters because hotter seas feed extreme rainfall and tropical cyclones, push sea levels higher and place coral reefs under severe stress.
The European Union’s Copernicus Marine Service said global sea surface temperatures averaged 21.0 degrees Celsius, or 69.8 degrees Fahrenheit, in June. According to the EU marine monitor, that surpassed the previous June records set in 2023 and 2024.
Copernicus said the first half of 2026 brought sustained high sea-surface temperatures and broad marine heatwaves across much of the planet’s ocean area. Simon van Gennip, lead oceanographer for the Copernicus Marine Service, said marine heatwaves widened steadily during that period and eventually affected about 82 percent of the global ocean.
Van Gennip said the Mediterranean, the central North Atlantic and the equatorial Pacific stood out as hot zones. He said those regional patterns pointed to oceans experiencing prolonged heat stress.
Scientists cited by Copernicus said the emergence of a potentially strong El Niño pattern could lift ocean and air temperatures further in 2026 and into next year. Carlo Buontempo, director of the Copernicus Climate Change Service, said current conditions may mark the start of another phase in which temperature records keep falling.
El Niño develops when parts of the Pacific Ocean become unusually warm, sending more heat into the atmosphere and affecting winds, clouds and weather systems worldwide. According to scientists, the pattern can increase the risk of extremes, including flooding in Peru, drought in parts of Africa and wildfires in Australia.
Al Jazeera and AFP reported that land and sea temperatures reached an all-time high in 2024 near the end of the previous El Niño. With another El Niño forming this year, scientists said 2026 could rank among the warmest years recorded.
The Copernicus findings follow a major United Nations scientific assessment issued last month. That assessment warned that the world’s oceans were in a worsening crisis as seas warmed and rose more quickly.
Oceans play a central role in regulating the climate because they absorb about 90 percent of the excess heat linked to greenhouse gas emissions, including carbon dioxide, according to the report. Warmer seas add moisture to the air, which can intensify tropical cyclones and heavy rainfall.
Hotter oceans also contribute directly to sea-level rise because water expands as it warms. Copernicus and UN scientists have also warned that prolonged marine heatwaves can create conditions that cause tropical corals to bleach and die.
This story draws on original reporting from Al Jazeera.