Global warming threatens the catastrophic extinction of marine life within 250 million years 2022-04-28 13:01:00

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New research has warned that global warming is causing such drastic change in the world’s oceans that it threatens the mass extinction of marine species that rival anything that has happened in Earth’s history over tens of millions of years.

The acceleration of climate change is causing a “profound” impact on ocean ecosystems “leading to greater extinction risk and less marine biological richness than has been seen in Earth’s history for the past tens of millions of years,” according to the study.

sea ​​water in the world Temperatures climb steadily Due to the excess heat from burning fossil fuels, while oxygen levels in the ocean decrease and water acidity increases from the absorption of carbon dioxide from the atmosphere.

This means that the oceans are getting increasingly hot gasping for breath The volume of ocean water completely depleted of oxygen It has quadrupled since the 1960s – And to become more hostile to life. Aquatic organisms such as oysters, mussels and shrimp are unable to form shells properly due to acidification of sea water.

All of this means the planet could slide into a “mass extinction that rivals those of Earth’s past,” according to the new research, Posted in Science. The pressures of warming and oxygen loss are uncomfortably reminiscent of the mass extinction event that occurred at the end of the Permian period about 250 million years ago, the researchers said. This catastrophe, known as the “Great Death”, led to its demise Up to 96% of the marine animals on the planet.

“Even if the magnitude of species loss was not at the same level, the mechanism of species loss would be the same,” said Justin Penn, a Princeton University climate scientist who co-authored the new research.

“The future of life in the oceans depends strongly on what we decide to do with greenhouse gases today. There are two very different oceans that we can see, one devoid of much of the life we ​​see today, depending on what we see as carbon dioxide emissions advance.”

The research found that truly catastrophic levels of extinction could be reached if the world released planet-warming gases in an unchecked manner, resulting in more than 4°C of average warming over pre-industrial times by the end of this century. This would lead to extinctions that would reshape life in the ocean for many more centuries as temperatures continued to rise.

But even in the best-case scenario, the world is still on the verge of losing a significant portion of its marine life. At a temperature of 2°C above the pre-industrial level, which is Probably expect Even under current climate pledges by the world’s governments, about 4% of the roughly two million species in the oceans will be eliminated.

Fish and marine mammals that live in polar regions are most vulnerable, according to the study, because they will not be able to migrate to cooler climates, unlike tropical species. They will have nowhere to go,” Ben said.

The threat of climate change amplifies other major threats to aquatic life, such as overfishing and pollution. The study found that between 10% and 15% of marine species are already at risk of extinction due to these various threats, based on data from the International Union for Conservation of Nature.

John Bruno, a marine ecologist at the University of North Carolina, who was not involved in the study, said the new research appears “sound” but differs from previous studies on the topic that suggested species would mainly spread to new areas rather than be entirely extinct.

“It is very different from what has been developed in most previous work,” Bruno said, but that does not mean they are wrong. “I think this new work challenges some of our current assumptions about the geographic patterns of looming ocean extinction.”

Bruno said that although mass extinctions are likely due to extreme warming in the future, the current impacts of climate change and other threats should be worrying enough for policy makers and the public.

“Personally, I am more concerned about the ecosystem degradation that we are already seeing after less than 1°C of warming,” he said.

“We don’t need to look at a world that’s too warm for humanity to be wiped out – we’re already losing countless diversity and an ecosystem that has functioned even with the relatively modest warming of the past 50 years.”

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