Earth is simmering in its hottest water temps on record, and that’s bad for fish and us

The world's oceans reached their hottest temperatures on record this past weekend, and are expected to continue warming in the coming months, according to the European climate service Copernicus. The ocean temperatures peaked at 21.1 degrees Celsius (70 degrees Fahrenheit) on Friday and Saturday, surpassing the previous record set in March 2024, according to Samantha Burgess, strategic climate lead for Copernicus.

The record-breaking heat is being fueled by a strong El Nino event, which is already the largest seen in recent years and continues to grow. Copernicus scientist Jane Lubchenco described the record as "very troubling," noting that a warmer ocean leads to destabilized weather patterns, threatens food security, economic prosperity, and marine life.

This warming also makes storms more intense and increases the risk of acidification and oxygen depletion in the ocean, which can harm industries reliant on marine resources. In Europe, warmer ocean temperatures exacerbate heat waves by eliminating the cooling effect of sea breezes. Typically, the Southern Hemisphere's sea surface temperatures peak in March and April as the southern summer winds down, but this year, the record was set in August.

The oceans are expected to keep getting warmer until the current El Nino peaks, which is anticipated between November and January.