The average surface temperature of the Atlantic Ocean has been rising steadily, reaching record levels since the beginning of the year. This phenomenon may not last, however, at least as far as Europe’s coastal waters are concerned. The surface temperature of the Atlantic Ocean began to exceed the levels reached in 2022 as early as March.
The surface temperature did not peak in early June as initially thought, but rose to 23 ˚ C on June 23, compared with 22.3 ˚ C in 2022, while the norm, corresponding to the average temperature between 1982 and 2011, is 21.8 ˚ C for this period. While temperatures are rising in both the North and South Atlantic, they are furthest from average in the North Atlantic.
Generally speaking, these abnormal temperatures have affected all oceans since spring, and are a direct consequence of global warming linked to greenhouse gas emissions. Jonathan Beuvier, a researcher at Météo France’s national meteorological research center, explains that the situation in the waters around Western Europe is mainly a consequence of the weather of recent weeks, in particular the very calm conditions over the British Isles.
He points out that the heat observed is limited to the first few meters and is an isolated surface layer. Overheating is not present at depth and, from thirty meters upwards, the water temperature around Western Europe is no longer considered abnormal.
For the scientist, what’s important is the vertical extent, and as this surface heat is isolated from what’s happening below, a little wind could cause it to mix with the waters below. He believes that weather conditions can quickly change the situation and that all it takes is a little windier weather over this part of the Atlantic Ocean to make a difference. The surface warmth around Western Europe is therefore unlikely to last long, as it does not extend very far at depth.
The situation would be different if the overheating were to last or be repeated in the coming months, or if it were to reach the deeper layers of the ocean. The overheating of another part of the Atlantic Ocean is more worrying. These are the waters stretching from the African coast, from the Western Sahara to Cameroon in particular, to the east coast of the United States and the Gulf of Mexico.
Cancún, Quintana Roo, Mexico
In this part, the temperature at a depth of thirty meters remains above average, reaching 29 ˚C in places. Heat anomalies are also observed at a depth of one hundred meters in some parts of this zone, notably along the US coast and from the West Indies to Brazil, and the heat anomaly can even reach three meters in places.
The heat of the water is the main trigger for tropical cyclones and hurricanes, as a cyclone can form when the temperature of the surface waters reaches or exceeds 28 to 29 ˚ C and the water, between the surface and sixty meters deep, reaches or exceeds 26.5 ˚ C. The temperatures currently observed therefore favor the formation of early cyclones in this area of the Atlantic, and it does not appear that the arrival of the El Niño phenomenon is sufficient to mitigate the risk of these disturbances forming…
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