The oceans record temperature records that worry scientists, who are now warning of their catastrophic consequences not only for the environment, but also for the economy in various parts of the planet.
"Prolonged heat in the oceans is not just an environmental problem," said Tom Pickerell, a marine biology expert and director of the oceans program at WRI (World Resources Institute), during a press presentation.
Fewer sardines for Moroccan fishermen, tourists who give up visiting degraded coral reefs and nuclear reactors stopped due to the proliferation of jellyfish, as recently happened in France, are some of the visible consequences of the phenomenon.
"A warmer ocean alters fisheries and food supplies, damages the reefs and beaches that support tourism, puts energy infrastructure under pressure, and fuels extreme weather events that affect coastal communities and businesses," said Pickerell.
For the biologist, the situation "should worry all finance ministers" in the world. The issue will be one of the main themes of the next climate summit organized by the UN, COP31, in November, in Antalya, under the joint presidency of Turkey and Australia.
The heat reached levels never recorded in August on a planetary scale. The average temperature of the oceans, without considering the polar regions, was 21.07 °C during the month, equaling the record reached in March 2024, the European Copernicus observatory reported this Thursday (10).
Furthermore, the summer of 2026 in the northern hemisphere, between June and August, was the hottest since 1993, according to the Copernicus Marine Service, due in particular to the natural phenomenon El Niño, whose current episode appears to be especially intense and adds to global warming caused by human activity.
"The driver of the record heat is climate change; it's the long-term trend," noted Zachary Labe, a climatologist at the Climate Central research center. According to the scientist, the oceans have just faced a series of "100 days of record heat" for this time of year.
The estimate is based on data, some still preliminary, on ocean surface temperatures, compiled by the United States National Oceanic and Atmospheric Administration (NOAA).
"I believe we will continue to talk about record temperatures, both in the atmosphere and in the oceans, at least until 2027," he added.
Ocean warming has many consequences. Firstly, it causes thermal expansion of water and therefore a rise in sea levels, which threatens especially vulnerable island nations in the Pacific and Indian Oceans.
It also intensifies heat waves that weaken corals, which are essential for the marine ecosystem, as they absorb carbon; reduces the abundance of fish in some areas, with consequent losses for fishermen. And it worsens extreme meteorological phenomena, such as torrential rains and cyclones.
"Marine heatwaves can lead to the closure of fishing areas due to disease, species mortality or simply because fish move to cooler regions of the ocean. This can cost affected communities millions or even billions of dollars, as well as having consequences for food prices," explained Kathryn Smith, from the British Marine Biological Association.
Pickerell cited as an example the decline of sardine populations in warmer Moroccan waters. "This led to a ban on exports and shortages on the European market," he said.
For scientists, there are few immediate solutions other than accelerating policies to combat climate change.
"On land, we can always install air conditioning to keep us cool. But the adaptation of the oceans and marine life is not so simple and remains very limited", recalled Claire Bergin, a researcher at Maynooth University, in Ireland.
