Extreme marine heat waves tripled over past 80 years, study finds

The number of days each year that the world's oceans experience extreme surface heat has tripled over the past 80 years due to global warming, a new study has found.

Researchers found that, on average, the global sea surface saw about 15 days of extreme heat annually in the 1940s. Today that figure has soared to nearly 50 days per year, according to a new study published this week in the journal Proceedings of the National Academy of Sciences.

Global warming is responsible for almost half of the occurrence of marine heat waves – periods when sea surface temperatures rise well above normal for an extended time.

The study, produced by a team of scientists from the Mediterranean Institute for Advanced Studies, the University of Reading, International Space Science Institute and the University of the Balearic Islands, also found that rising global temperatures are making extreme ocean heat events last longer and become more intense.

"Marine heat waves can devastate underwater ecosystems. Extended periods of unusually warm water can kill coral reefs, destroy kelp forests, and harm seagrass meadows," said Xiangbo Feng, a co-author of the study at the National Centre for Atmospheric Science at the University of Reading.

The impacts of marine heat waves extend beyond the ocean. The researcher warns that increased marine heat waves could, in return, cause our atmosphere less stable leading to more frequent and powerful tropical storms in some regions.