In a new study published in Geophysical Research Letters, researchers detail how marine cold spells are decreasing as the climate warms. These cold spells are occurring at a rate of about 25% that of the rate in the 1980s, and they are turning out to be 15% less intense.

Now, this news is good and bad. Less intense cold spells are not as likely to cause mass die-off events among marine life but having fewer of these cold spells also means no respite from the warming oceans. Or as lead author, Yuxin Wang, explains: Marine cold spells play dual roles in influencing ecosystems. They can cause devastating impacts, like coral bleaching and mass mortality events. But cold spells can offset the impacts of heatwaves.

Wang and her team analyzed the temperatures of sea surfaces from 1982 to 2020, looking for cold spells and heatwaves. They found that the oceans are definitely getting warmer, as expected based on global warming trends, and the surface temperatures are becoming more and more variable. And all those variations mean that the heatwaves and cold spells are changing at different rates, making them difficult to predict.

And predicting these variations in temperature is important for understanding the potential impact on not only marine life like coral reefs but also on industries such as fisheries. Oceanographer Sofia Darmaraki, who was not involved in the study, notes: Extreme events affect coastal communities and economies, but members of the public might not be aware of how they’re going to intensify in the future. We need to get the word out. Information about the underlying, physical causes of these extreme events can help improve forecasting, which can lead to the development of early warning systems. That information can be provided to fisheries and other stakeholders, and they can collaborate on the best adaptations, the best path forward.”

We really, really need to take care of our planet.

More Information

AGU press release

“Understanding the Changing Nature of Marine Cold-Spells,” Yuxin Wang et al., 2022 March 17, Geophysical Research Letters