A record with no rival
The ocean is hotter than at any point in recorded history. Copernicus, Europe's climate monitoring service, announced that daily global sea surface temperature has reached its highest level since measurements began. The new record follows a year of already extreme ocean heat, and the margin is not small. The reading applies to the global average across all ice-free ocean areas, a measure that smooths out local variation and gives a clear view of the overall trend. The previous peak was set only last year, which shows how quickly the ocean is heating.
Why El Niño matters
Part of the heat comes from El Niño, a natural climate pattern that warms the tropical Pacific. When El Niño is active, it pushes global temperatures upward on top of the long-term trend. Scientists say the combination of El Niño and greenhouse gas emissions has pushed the ocean past thresholds that once seemed distant. They warn that El Niño will eventually fade, but the underlying warming will not. El Niño events arrive every few years and typically last about a year. Their effects ripple across the planet, from rainfall patterns in Africa to winter weather in North America.
What warmer oceans mean
The consequences are already visible. Coral reefs are bleaching from the Great Barrier Reef to the Caribbean. Marine heat waves are driving fish toward cooler waters and disrupting fisheries that millions of people depend on. Warmer oceans also power more intense hurricanes and typhoons. And there is a feedback loop: a warmer ocean absorbs less carbon dioxide, which means more CO2 stays in the atmosphere. Researchers describe the ocean as under unprecedented strain, and they say the only lasting fix is to cut emissions at the source. Coastal communities are also feeling the impact, as warmer water expands and contributes to sea level rise. Scientists say the record is consistent with long-term projections, not a surprise.