Swiss scientists from the University of Bern discovered another danger of global warming as part of their study. As it turned out, this process becomes the cause of the “heat waves” appearing in the oceans and deadly in their properties.
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This phenomenon also occurs on land, but in 2013, an impressive accumulation of abnormally hot water from the Pacific Ocean near the coast of North America was noticed. This “influx” led to the death of some animals. In addition, against the background of active growth of cyanobacteria, “blooming” took place together with the accumulation of toxins. Certain tropical fish species had to move to normally cool waters, which affected the breeding cycle. Scientists estimate that cod alone killed about 100 million individuals. At the time of the anomaly, the water temperature turned out to be 4 degrees higher than usual, and the area completely “resolved” only in 2015. The case is not unique, the same thing happened in other oceans. New work of scientists shows that against the background of global warming, such “heat waves” are more than ten times more frequent than before.
In an article on the pages of Science, the authors of the study analyzed observational data for 300 of the most striking examples of such an anomaly in the waters of the World Ocean, covering the period 1981-2017. As a result, it was found that the duration of the “heat waves” averaged about 40 days, they also covered about 1.5 million square kilometers, and the increase could be up to 5 degrees above normal. Over the years of observations, the frequency of such events, their duration and intensity have increased.
In the next stage, the authors of the work focused on the seven most powerful “heat waves” in the ocean. Previously, such events took place only once every couple hundred or even a thousand years, as indicated by modeling. However, if the temperature rises by 1.5 degrees, the “influx” will occur once a decade, by 3 degrees – annually. Only if the global rise in temperatures stopped, the ocean eventually managed to restore the heat balance, and the frequency of “heat waves” dropped.