In the oceans, record temperatures are alarming

“Marine heatwaves have significant and potentially devastating impacts.”According to the European Copernicus Institute. “Nine consecutive months of record temperatures.”According to National Oceanic and Atmospheric Administration (Noaa) American. “The energy absorbed in one year is enough to boil 2.3 billion Olympic-size swimming pools.”says a study published by the magazine Advances in atmospheric science, January 11. Throughout 2023, the hottest year since records began, scientists around the world have had to compete in vocabulary innovation to describe the situation in the oceans and seas.

The tropical Pacific, the North Atlantic, the Mediterranean, the Caribbean… All regions remained red for a long time, and the temperature anomalies were often more impressive than those observed in the atmosphere. “We have had an exceptional year, due to the direct impacts of climate change and natural fluctuations with El Niño.summarizes Julie Deshaies, a climate scientist at the Laboratory for Oceanography and Climate: Numerical Experiments and Approaches (LOCEAN). It is actually exceptional compared to the past and normal compared to the future that awaits us due to greenhouse gas emissions. Now is the time to do everything we can to reduce emissions, if we want to have any chance of staying at this level in the coming years. »

Globally, the average surface temperature (sea surface temperature, SST) measured around the world has broken its monthly records.April to December 2023, reaching an unprecedented level of 21.1 degrees Celsius on August 23 and 24. The previous record of 20.95°C was set in March 2016 near the end of a strong El Niño wave.

A dynamic that continued in January 2024 with new high points on January 10 and 20 (21.1°C). A specially inspected place,North Atlantic Exceptional sea surface temperature was experienced from June to December, with anomalies well above average. On 31 August 2023, the sea surface temperature reached a record high of 25.19°C (the previous highest North Atlantic daily temperature was 24.81°C, recorded in September 2022), and 0.91°C was at -above average. In the northeastern Atlantic, the exceedance reached +1.36°C.

These paths caused marine heatwaves in several regions of the world (+4 degrees Celsius west of Ireland). “These are values ​​that exceed all expectationssums up Karina von Schuckmann, an oceanographer specializing in Earth's energy imbalance within the Mercator International Ocean Organization. There have been anomalies favored by natural fluctuations, underwater volcanic eruptions… but they are still very high in the averages due to the global warming predicted by the models, even if we are at the top of the tracks. »

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