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Home / Science / A new study on the worst mass extinction in the world should make you very nervous for our future. – Mother Jones

A new study on the worst mass extinction in the world should make you very nervous for our future. – Mother Jones



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About 250 million years ago, when the world still consisted of the only supercontinent pangea, a geological system The catastrophe erased nearly all creatures living on the planet: fish, crustaceans, molluscs and even microbes. Only 4 percent of the marine animals survived, including the Nautilus. On land, about 30 percent survived. It was the worst extinction in the history of the earth.

Accordingly, the event was referred to by scientists as "Great Dying" (also known in science as "Permian-Triassic extinction"). However, despite the extent of the disaster, paleontologists only found evidence of the fossil record in the last two decades ̵

1; and discovered that it was in today's Siberia with a massive volcanic event coincided.

Yet, there was a big Blindo point in the scientists' knowledge of the big dying: while they knew about the extinction and knew about the volcano eruption, it was unclear how the two were related and what exactly was causing the massive demolition , Scientists had long suspected that the release of greenhouse gases through the volcano into the atmosphere played a role, although they did not know the exact mechanism by which this happened. (It's as if a doctor knows that a person was killed in a car accident but can not determine the exact cause of death.)

Well, a new study was published in the journal on Thursday , Science suggests that the doer of the Great Death – and the connection between the two events – is probably something the planet is all too familiar with today: global warming and, as a consequence, high sea temperatures and water loss [19659004] And it turns out that this million-year-old event can serve as a warning to our own future. The authors write that the combination of these two factors – warming of water and lack of oxygen – "can account for more than half of the size of the" big death "in the ocean. Of course, both factors still play a role.

"These extreme events are so important because they give us an insight – what are the limits of climate change?" Woodward Fischer, a professor of geobiology at Caltech University, recounted the study and did not participate in the study was Mother Jones . "What are the limits of environmental change? And how do these feedbacks affect the biosphere? It's kind of a question to ask, "Well, what's possible?"

So, the authors came to their conclusion: While scientists had long suspected that a warming climate played a role in the Great Dying, they had not come up with one Way to prove it. To test the theory, the team simulated global warming with a model of the Earth's climate and predicted how ocean warming and oxygen depletion could affect the survival characteristics of ancient marine animals, based on the tolerance levels of today's wildlife, including fish and crustaceans , Sharks, corals and mollusks. It was not a perfect model (not a model), but it does serve as an approximation to how sensitive ancient species were to a warming climate at the time. To see how the model stood up, it was compared to the fossil record.

It has shown a spectacular performance. Not only was it consistent with the fossil record, it even predicted something that paleontologists had never noticed: the creatures living near the equator were more likely to survive a greater warming than those near the poles. Presumably, people living at the equator could travel north into cooler waters as temperatures rose while they were trapped by the masts. (That does not mean that the tropics are a useful haven, the majority of species still died there.)

"The percentage of marine animals extinct at latitude after Permian time out of the model (black line ). and from the fossil record (blue dots).

University of Washington

"The model made this prediction when we did not even really know if it was true," said Curtis German professor of chemical oceanography at the University of Washington and one Author of the study, tells Mother Jones . "So we went to the paleontologist colleagues and they had to look for it [in the fossil record]. And when they did, it was a funny "Eureka" moment. "

In summary, the researchers revealed that a warming sea and thus low oxygen content of the water actually played a crucial role in the Great Dying.

Understanding the turbulent past of the planet is an important thing, but it is much more urgent What we can learn from this for the future German calls the Great Dying a "warning story" for understanding today's climate change.

"The way in which we warm the ocean with greenhouse gases and exhaust the ocean's oxygen inventory is he said, "one way the earth has been," "Where we are is not exactly the same scenario as before the Great Dying," he adds, "But the basic way to warm the ocean, as it loses its oxygen, marine ecosystems will now cause the same kind of stress as it did then.

At the time of the Great Death, Earth's temperatures had risen by 10 degrees Celsius. While this is expected to be far from the three or four degrees of warming that scientists expect in the next century, it is "not on and a completely different aircraft ," says Deutsch. S o Unless otherwise, the study draws attention to a crucial point where we can expect a dramatic environmental catastrophe, said Justin Penn, a Ph.D. student at UW and principal author of the study. "If you warm the ocean 10 degrees, you will be endangered and the worst in Earth history," he says. (On Wednesday, a report by Stanford University published in the journal Environmental Research Letters that carbon dioxide will reach another record in 2018.)

The idea of ​​mass extinction in the near future unnecessarily paints a gloomy picture. In short, it would be biological Armageddon. The big difference, of course, is that the animals had no choice at the time of the Great Death and had no control over what happened to their planet. While people are following a similar path and are "a significant part of the path to extinction," Deutsch says, "we do not know how far we will get – and it depends a lot on what we decide." [19659022]
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