Ocean warming has already had a significant impact on many fisheries around the world, leading to population losses of up to 35% in some areas.
This is the conclusion of a first study, published Thursday in the scientific journal Science, which used historical data on fish stocks and temperature maps to measure the effect of warming waters on 235 populations of fish and fish. between 2010 and 1930. The team of six researchers estimates that the warming of the ocean during this period resulted in an estimated 4.1% reduction in the amount of fish that can be captured in a sustainable manner. from 35.2 million metric tons in the 1930s to 33.8 million metric tons in the 2000s.
"We were really surprised to see that the warming has already had a very important impact," Chris free, lead author of the study and postdoctoral ecologist at the University of California at Santa Barbara, told HuffPost.
Nineteen fish populations experienced negative population growth rates as a result of climate-induced ocean warming, while nine others benefited from changing conditions. The populations studied represent more than 120 species and about one third of the declared world catches.
The North Sea, located in the north-west of the United Kingdom, as well as the East China Sea and the Sea of Japan, are the regions hardest hit by rising ocean temperatures. Estimated losses in these areas ranged from 15 to 35%.
"The North Sea supports very important commercial fisheries. And these East Asian ecosystems are home to some of the fastest growing human populations and populations that rely heavily on seafood, "said Free. "These impacts are really a big problem."
According to the findings, overfishing has only exacerbated the problem, making fish populations less resilient to climate change. In addition, the study notes that "climate change is likely to hinder efforts to rebuild overexploited populations".
Free overfishing calls for a "one-two" for heat-stressed fisheries. Eliminating overfishing and taking climate change into account in fisheries management decisions will be key to building resilience in a world where people are increasingly relying on fish as a food source. he declared.
According to the United Nations, about one third of the world's oceans are overexploited.
The new study, led by scientists from Rutgers University, is the first to quantify the historical impact of global warming on fish populations around the world, according to Free, who obtained his doctorate at the University of California. # 39; school.
The average global temperature on Earth has increased by about 0.8 degrees Celsius since 1.480. According to a United Nations report released last October, if humans continue to release greenhouse gases into the atmosphere at the current rate, global warming is expected to reach 1.5 degrees Celsius between 2030 and 2052 resulting in damage estimated at $ 54 trillion. An analysis conducted earlier this year revealed that the oceans were warming up to 40% faster than expected, as reported by the New York Times.
Olaf Jensen, co-author of the study and associate professor in the Rutgers Department of Marine and Coastal Sciences, warned Olaf Jensen, many of the species that have benefited so far.
"Fish populations can not tolerate so much warming," he said.