Madrid (AFP) – While vacationers may enjoy the warmth of summer in the Mediterranean, climate Scientists are warning of dire consequences for marine life as it burns up in a series of intense heat waves.
From Barcelona to Tel Aviv, scientists say they are seeing exceptional temperature rises ranging from 3°C (5.4°F) to 5°C (9°F) above normal for this time of year. Water temperatures regularly exceed 30 °C (86 °F) on some days.
Extreme temperatures in Europe and other countries around the Mediterranean made headlines this summer, but sea warming is largely out of sight and largely out of mind.
Marine heat waves are caused by ocean currents that consist of areas of warm water. Weather and temperature systems in the atmosphere can also accumulate in degrees of water temperature. Like their terrestrial counterparts, marine heat waves are longer, more frequent and intense due to human-caused climate change.
The situation is “extremely worrying,” says Joaquim Garrabo, a researcher at the Institute of Marine Sciences in Barcelona. We push the system too far. We have to take action on climate issues as soon as possible.”
Garrabou is part of a team that recently published a report on heat waves in the Mediterranean between 2015 and 2019. The report says these phenomena led to a “massive mortality” of marine species.
About 50 species, including corals, sponges and seaweeds, were affected along thousands of kilometers of Mediterranean coasts, according to the study published in the journal Global Change Biology.
The situation in the eastern Mediterranean basin is particularly dire.
The waters off Israel, Cyprus, Lebanon and Syria are “the hottest hotspot in the Mediterranean, for sure,” said Gil Riloff, a marine biologist at the Oceanographic and Lakes Research Institute in Israel and one of the authors of the research paper. Average sea temperatures in summer are consistently above 31 °C (88 °F).
Warming seas are pushing many native species to the brink, he said, “because each summer the optimum temperature is exceeded.”
What he and his colleagues are seeing in terms of biodiversity loss is what is expected to occur westward into the Mediterranean toward Greece, Italy and Spain in the coming years.
Garbo points out that the seas served the planet by absorbing 90% of the Earth’s excess heat and 30% of the carbon dioxide emitted into the atmosphere by producing coal, oil and gas. The effect of carbon sequestration protects the planet from the effects of more severe weather.
This was possible, Garbo said, because the oceans and seas were healthy.
“But now we’ve pushed the ocean into an unhealthy, dysfunctional state,” he said.
While Earth’s greenhouse gas emissions must fall dramatically if sea temperature rise is to be curbed, oceanographers are specifically looking for authorities to ensure 30% of marine areas are protected from human activities such as fishing, giving species a chance to recover. and prosperity.
About 8% of the Mediterranean area is currently protected.
Garbo and Rylov said policy makers are largely unaware of the warming of the Mediterranean and its impact.
“It is our job as scientists to get this to their attention so they can think about it,” Rylov said.
Heat waves occur when particularly hot weather persists over a specified number of days, with little or no rain or wind. Earth heat waves help create marine heat waves and the two tend to feed each other into a vicious warm cycle.
Global heat waves are becoming common in many countries around the Mediterranean, with dramatic side effects such as wildfires, droughts, crop losses and excruciatingly high temperatures.
Scientists say marine heat waves could also have devastating consequences for countries bordering the Mediterranean and the more than 500 million people living there if they are not addressed soon. Fish stocks will be depleted and tourism will be negatively affected, as devastating storms could become more common on Earth.
Although it represents less than 1% of the global ocean surface area, the Mediterranean is one of the major reservoirs of marine biodiversity, containing between 4% and 18% of the world’s known marine species.
Some of the most affected species are key to maintaining the functioning and diversity of sea habitats. Species such as the meadows of Posidonia oceanica seagrass, which can absorb huge amounts of carbon dioxide and harbor marine life, or coral reefs, which are also home to wildlife, will be at risk.
Garrabou says the effects of mortality on species have been observed between the surface and a depth of 45 meters (about 150 feet), where the recorded marine heat waves were exceptional. Heat waves affected more than 90% of the surface of the Mediterranean Sea.
According to the latest scientific papers, sea surface temperature in the Mediterranean Sea increased by 0.4°C (0.72°F) every decade between 1982 and 2018. On an annual basis, it has been rising by about 0.05°C (0.09°F) above the past decade below No signs of surrender.
Experts say even parts of the degrees can have disastrous effects on ocean health.
The study notes that the affected areas have also grown since the 1980s and now cover most of the Mediterranean region.
“The question is not about the survival of nature, because biodiversity will find a way to survive on this planet,” Garabo said. “The question is if we keep going in this direction, maybe our society, humans, will have nowhere to live.”
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Ilan Ben-Zion reported from Jerusalem.
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