Study Reveals 2023 Set a Record for Marine Heatwaves

Here’s something you’ve probably noticed in recent years: it’s been getting hotter. The planet is setting new high temperature records, which has an effect on everything from travel plans to mental health. That doesn’t just mean that it’s hotter outdoors, though: a newly-published study reveals that record-setting temperatures are also happening in the aquatic realm. And if you think that could have implications outside of the water as well, you are correct.

The title of the paper, published earlier this month in Science, gets right to the point: “Record-breaking 2023 marine heatwaves.” The authors note that marine heatwaves “[set] new records in duration, extent, and intensity” in 2023 and were significantly above “the historical norm since 1982.”

As Perri Thaler reported in Live Science, the heatwaves covered 96% of the planet’s oceans. Marine heatwaves mean more than just uncomfortable temperatures the next time you go swimming. Instead, as Ryan Walter of California Polytechnic State University told Live Science, marine heatwaves can have a destructive impact on oceanic life. In 2023, NASA scientist Angela Colbert, Ph.D. wrote that “the total heat stored by the oceans (ocean heat content) rose 187 zettajoules from 1992 through 2019. And most corals can’t take the heat.”

A paper published last year in Nature Communications looked at the impact of marine heatwaves on nearby ecosystems. In this case, the researchers observed that the effects of marine heatwaves included “disrupted or novel communities and changes in predator-prey relationships, which likely lead to changes in the overall structure of marine ecosystems as a consequence of MHWs.”

Live Science’s report on the Science study points to another area of interest for scientists: whether 2023 represents a “tipping point” for oceanic temperatures. One of the scientists who Live Science spoke with pointed to the strength of El Niño in 2023 as a potential factor in the record-breaking marine temperatures. Those temperatures are still trending upwards over time, though — and even without setting a record in 2023, these marine temperatures are still worrisome.