The world’s oceans are warming at an unprecedented rate. According to the EU Copernicus’ 8th Ocean State Report released this week, the rate of ocean warming has nearly doubled in the last 20 years.
Roughly 22% of the global ocean surface experienced at least one severe to extreme marine heat wave event in 2023, according to the report. Polar ocean warming is especially pronounced; 2023 had the least polar sea ice ever recorded. Each decade of the last nearly 50 years saw a 4% loss of Arctic sea ice as surface water temperature increased.
The findings mirror the Intergovernmental Panel on Climate Change (IPCC) report on the ocean and cryosphere, which also shows that global warming caused by greenhouse gas emissions has resulted in marine heat waves.
According to the Ocean State Report, record-breaking events have also been observed in European seas. In 2022, the water around the Balearic Islands, off the east coast of Spain, rose to its highest temperatures in the last 40 years. The west coast of Europe, the region between Spain and Ireland, experienced heat waves that lasted a maximum average of 145 days.
Parts of the Barents Sea, north of Scandinavia in the Arctic, have “entered a state of “permanent” marine heat wave, report author and oceanographer Karina von Schuckmann told Agence France-Presse.
Schuckmann said such a sustained increase in ocean temperatures affects nearly every aspect of the marine ecosystem. The report highlighted decreased marine biodiversity due to migration of species, mass die-off events and invasive species. Ocean stratification is also exacerbated as marine heat waves “reduce the capacity of ocean layers to mix and therefore hamper the distribution of nutrients,” the report notes.
Ocean waves are also increasing in height. The Ocean State Report cited waves recorded in Melilla, Spain, which reached 7 meters (23 feet) high in April 2022. The massive waves hit a harbor during a violent record-breaking storm.
The annual publication by the Copernicus Marine Service is implemented by Mercator Ocean International. The recent report is based on satellite observations, in situ measurements and the latest computer modeling technology. More than 100 experts from around the world worked on the report.
Banner image by Thomas Horig / Ocean Image Bank
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