A study looked at how heat waves in the atmosphere cause water temperatures around 30.8 ° C. This record temperature was reached last August in the northwestern Mediterranean, shortly after the third heat wave that the France suffered.
Ocean warming is linked in particular to "atmospheric blockages" on the surface. According to an IPCC report on "the ocean and cryosphere in the context of climate change", published in 2019, there could be 20 to 50 times more between 2081 and 2100 than over the period 1850 – 1900.