Ocean-surface warming four times faster now than late-1980s

The rate of ocean warming has more than quadrupled over the past four decades, a new study has shown. Ocean temperatures were rising at about 0.06 degrees Celsius per decade in the late 1980s, but are now increasing at 0.27 degrees Celsius per decade. Published today (Tuesday, 28 January 2025) in Environmental Research Letters, the study helps explain why 2023 and early 2024 saw unprecedented ocean temperatures.

This accelerating ocean warming is driven by the Earth’s growing energy imbalance – whereby more energy from the Sun is being absorbed in the Earth system than is escaping back to space. This imbalance has roughly doubled since 2010, in part due to increasing greenhouse gas concentrations, and because the Earth is now reflecting less sunlight to space than before.

Global ocean temperatures hit record highs for 450 days straight in 2023 and early 2024. Some of this warmth came from El Niño, a natural warming event in the Pacific. When scientists compared it to a similar El Niño in 2015-16, they found that the rest of the record warmth is explained by the sea surface warming up faster in the past 10 years than in earlier decades. 44% of the record warmth was attributable to the oceans absorbing heat at an accelerating rate.

Source: Eurek Alert!