Sea Surface Temps Hit a Not-Great Milestone

The world's oceans just notched a milestone scientists hoped wouldn't arrive this fast, the Washington Post reports. Data from Europe's Copernicus Climate Change Service show the average global sea surface temperature climbed to nearly 70 degrees Fahrenheit late last week, edging past the previous record set in March 2024—and likely setting a high not seen in thousands of years.

University of Ottawa professor Ryan Katz-Rosene wrote on X that Aug. 21 probably marked the warmest ocean surface since the Holocene began some 12,000 years ago, and possibly since the last interglacial period about 125,000 years back. The heat is not abstract: roughly 42% of global oceans are now in marine heat wave conditions, helping energize storms like Hurricane Lala near Hawaii, turbocharging heavy rainfall in the US, and amplifying Europe's summer heat. A climate scientist who spoke to Scientific American says that "without reductions in the burning of fossil fuels, this warming will only continue." The currently developing El Nino event, predicted to be the hottest in at least 100 years, is also helping to drive higher ocean temps, the Guardian reports.