World ocean surface temperature hits record 21.1°C, Copernicus says

September 6, 2026 at 10:01 AM2 min

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The average surface temperature of the world ocean reached 21.1 degrees Celsius, the highest on record, according to the European climate service Copernicus. The previous record was set two years ago. Climate scientists say the warming is disrupting marine ecosystems and intensifying heatwaves and storms on land.

Key Facts

The average surface temperature of the world ocean reached 21.1°C, the highest since records began, according to Copernicus.
The previous record was set two years ago.
Copernicus climate service head Samantha Burgess said warming oceans stress corals and marine life, deplete oxygen and nutrients, and cause fish deaths and harmful algal blooms.
Climate scientist Theodore Kiping said the probability of nearly all extreme weather events, except abnormal cold, increases as the climate warms.

Record Ocean Temperature

The world ocean's average surface temperature reached 21.1 degrees Celsius, the highest in recorded history, according to the European climate service Copernicus. The previous record was set two years ago. The main causes are global warming and the El Niño phenomenon.

Impact on Ecosystems and Weather

Copernicus climate service head Samantha Burgess said warming oceans put corals and other marine organisms under enormous stress. She said oxygen and nutrient deficits in warm water lead to fish deaths and abnormal blooms of dangerous algae. Burgess added that a warmer ocean directly affects life on land, citing Europe's summer heatwaves intensified by the loss of nighttime cooling from sea breezes. Climate scientist Theodore Kiping said the probability of nearly all extreme weather events, except abnormal cold, rises as the climate warms.

Call for Clean Energy

Experts warn that as long as greenhouse gas emissions grow, the climate will continue to change. They say it is important to gradually reduce dependence on coal, oil, and gas while developing renewable energy sources. Large-scale deployment of clean technologies could help slow the pace of global warming.