The record for the average sea surface temperature of the world’s oceans for the month of August was broken on Saturday, August 22.
Figures released by the Copernicus Climate Change Service (C3S) confirm that the average sea surface temperature outside the polar regions reached 21.1 degrees Celsius on August 22, breaking the previous record of 21.09 degrees Celsius.
This milestone comes on the heels of a series of records and near-record levels in the monthly average sea surface temperature recorded throughout 2026.
According to the C3S, this milestone is consistent with the long-term, ongoing warming of the global ocean and the emergence of an extreme El Niño event in the tropical Pacific Ocean.
A strong El Niño event is currently developing in the tropical Pacific, adding even more heat to an ocean that has already been warming for decades as a result of human-induced climate change.
The World Meteorological Organization (WMO) has warned that El Niño is expected to intensify in the coming months, while the C3S seasonal forecast system suggests that the phenomenon could reach levels not seen in several decades.
A warmer ocean could also contribute to rising sea levels and damage key ecosystems, such as coral reefs and seagrass beds, which in turn disrupts marine food webs and industries such as fisheries and aquaculture.
Oceana’s senior marine scientist, Dr. David Costalago, stated in a press release that these record-breaking ocean temperatures are yet another unmistakable warning sign that the climate crisis is already here and affecting us all.
Dr. Costalago added that the current Super El Niño is adding extra heat to the system, but that the underlying cause is decades of human-induced greenhouse gas pollution.
“The ocean has quietly absorbed the vast majority of the excess heat from our atmosphere, effectively protecting us from even more rapid warming on land.
“But that protection comes at a very high cost,” he added.
“These extraordinary temperatures could also serve as an early warning that we are approaching dangerous tipping points in the ocean and the climate system, with unpredictable consequences for the planet.”
Dr. Gabby Ahmadia, vice president of the Marine Landscapes and Ocean Science Program at WWF-US, stated that increasingly warmer oceans are pushing coral reefs to their limits and making it difficult for them to survive and recover.
Dr. Ahmadia added that leaders in the public and private sectors must take action to reduce the emissions driving ocean warming and protect the reefs most likely to be resilient.
“Every fraction of a grade matters. Every year of delay matters,” he added.
Sophie Benbow, marine director of the conservation organization Fauna & Flora, stated that there can be no healthy planet without a healthy ocean, and that the ocean has been “acting as our safety net for far too long.”
Benbow added that, as the ocean warms, its ability to absorb carbon dioxide decreases, and marine life will be decimated.
“The message has never been more urgent: we must curb human-induced climate change and protect important blue carbon ecosystems, such as seagrass beds, mangroves, and kelp forests,” he said.
Fatima Candace Vahlsing, vice president of climate at Ocean Conservancy, said that breaking one heat record after another doesn’t have to become the new normal, but it does require a shift away from business as usual.
He added that investing in clean ocean energy, such as offshore wind power, will help meet growing energy demand while ensuring that today’s children and grandchildren continue to have fish to catch and safe waters in which to swim.
And Brian O’Donnell, executive director of the global conservation initiative Campaign for Nature, stated that warmer waters are driving fish away from their traditional habitats, leaving fishermen with smaller or less predictable catches. O’Donnell added that two key measures are needed to address record ocean warming.
First, he pointed out that fossil fuel emissions must be reduced rapidly, and second, it is essential that countries protect marine and coastal ecosystems.
O’Donnell stated that seagrass beds, mangroves, and salt marshes absorb carbon, and that coral reefs provide protection from storms and serve as habitats.
“More than 190 governments have committed to protecting and conserving at least 30% of the planet by 2030, and now is the time to turn that commitment into effective and lasting conservation on the ground,” he said.
“That will require a much greater investment in nature, including support for indigenous peoples and local communities, who play a vital role in protecting many of the world’s most important ecosystems.”
