Global oceans reached unprecedented warmth in June 2026, with sea surface temperatures climbing to nearly 21°C — the highest ever recorded, according to the Copernicus Climate Change Service (C3S) and Copernicus Marine Service. This alarming milestone underscores the accelerating pace of climate change and signals growing risks for marine ecosystems, weather patterns, and global communities.
A New Threshold
The average sea surface temperature across the world’s oceans — which cover two-thirds of Earth’s surface — hit 20.98°C in June, surpassing the previous record of 20.89°C set in 2024. The first half of 2026 is now the second warmest on record, trailing only the first half of 2024.
El Niño Meets Human-Caused Warming
This extreme heat stems from a convergence of natural and human-driven forces: the ongoing El Niño event — a periodic climate pattern that warms ocean surfaces near the equator —叠加 with long-term global warming caused by greenhouse gas emissions. El Niño typically intensifies droughts, floods, and heatwaves worldwide, and experts warn this year’s event could rank among the strongest ever observed.
Hotspots and Heatwaves
Temperatures spiked most dramatically across the central and eastern equatorial Pacific — the region most affected by El Niño. There, the tropical Pacific recorded its warmest first half-year in history at 26.91°C, narrowly beating the prior record set in 2016.
Oceans act as Earth’s climate regulator, absorbing about 90% of excess heat trapped by human-caused greenhouse gases — primarily from burning coal, oil, and gas. But that capacity is straining: since the start of 2026, marine heatwaves have been detected across 82% of the world’s ocean surface. Nearly half of that area is experiencing strong to extreme conditions.
A Warning for the Future
“Current conditions may signal the beginning of a new phase — one that takes us, once again, into uncharted territory,” warned Carlo Buontempo, Director of C3S. “With ocean temperatures at these levels and El Niño looming, more temperature records are likely to fall in the coming months.”