John Nazca via Reuters
Climate – “Exceptional” and very worrying. the sea The Mediterranean Sea The heat broke records this summer. This Sunday, July 24, the water temperature will reach 30 degrees Celsius (as on July 22) on the coast of the east coast of Corsica, Geraunos, the observatory French, warned of hurricanes and heavy thunderstorms. A Rising temperature It is already disrupting the Mediterranean ecosystem Proliferation of jellyfish.
“The thermal anomaly of the western Mediterranean is exceptional, sometimes exceeding 5 ° C off the coast of Provence,” the study center explained, while several sectors along the Mediterranean coast were put on alert for a heat wave on Monday.
Sea temperature is expected to reach 30°C (as of 22/7) afloat along the east coast. #Corsica (Alistro).
Thermal anomalies are exceptional in the western Mediterranean, sometimes > 5°C off the coast of Provence. #heatwavepic.twitter.com/DJ6YvplzNa— Keraunos (@KeraunosObs) July 24, 2022
Long ocean heat waves soon?
Sea Surface Temperature (SST) is +5°C above average along the coasts of Spain, France and Italy, as seen based on data from the visualization below. Copernicus Marine Service. “Except for the Alboran Sea (between Morocco and Spain), the entire western Mediterranean has been experiencing a marine heat wave since May 16,” Robert Schlegel described., A researcher from the Institut de la Mer de Villefranche (IMEV) interviewed at the end of June The HuffPost.
Copernicus
Bad news that could get worse. “By 2050 we are all locked into a scenario the sea The world will be close to a point Heat wave An almost stationary fleet”, warns Robert Schlegel. In the current climate, ocean heat waves last only a fortnight in the Mediterranean. In the worst-case scenario predicted by the IPCC, with +5°C warming, simulations predict four months longer and four times longer, from the Mediterranean to the sea. A study on the evolution of heat waves reports. CNRS.
“Between 1925 and 2016, the number of annual days of ocean heatwaves in the world increased by more than 50%,” reports physical oceanographer Carol Saud-Grid. The HuffPost. These figures come from a study in the journal Science Natural climate change In this, researchers make a direct link between the increase in these heat waves and the long-term warming of the oceans.
Even if we could limit warming to +2°C, “almost all oceans will experience more frequent and longer ocean heat waves,” the researcher continues. In terms of consequences, past ocean heat waves predict major changes in ecosystems, fauna and flora. In 1999, 2003 and 2006, the Mediterranean was hit by a heat wave, “massive mortality events of many species”, laments the National Center for Scientific Research (CNRS).
New oxygen-free zones have appeared in the Indian Ocean and the Pacific in recent years, and hypoxic gyres have recently been discovered in the eastern Atlantic. A state of hypoxia occurs when the amount of oxygen in seawater is insufficient to meet the needs of marine animals that need this oxygen.
Proliferation of small purple jellyfish in the Mediterranean Sea
Another consequence of the warming of the Mediterranean Sea is Pelagia noctiluca, tiny purple jellyfish that are being washed up by the dozens on beaches. “These episodes of proliferation are not new and have been described in antiquity,” he explained HuffPost Mélanie Ourgaud, oceanographer, marine biologist and researcher at CNRS. But global warming is not the only cause of this increase.
“For jellyfish Pelagia noctiluca, ocean currents play an important role,” the scientist added. They belong to the plankton family, so they cannot swim, and like all members of this family, they are carried by ocean currents.
It also drives another cause, again human: overfishing. “There are not enough of the main predators (turtles, tuna, etc.) to eat the jellyfish, and the stocks of zooplanktonivores (sardines, anchovies, other small blue fish) that consume zooplankton (food resources like jellyfish) have decreased. The Fish shortage “This is a positive factor for the growth of jellyfish,” lamented Melanie Orcott. Clearly, this proliferation of jellyfish confirms the health status of our oceans and presents threats to the marine environment.
See more The HuffPost: These images of the largest salt lake in the US are drying up
“Web specialist. Infuriatingly humble coffee ninja. Wannabe zombie advocate. Subtly charming tv fanatic. Avid social media scholar.”