The Great Dying: UT Study Says Climate Change Elevated Mass Extinctions

 

Sixty-five million years ago, the earth faced one of the most infamous periods of mass extinction. Though the Cretaceous-Paleogene extinction event failed to completely kill off mammals, birds, and sea creatures, it effectively wiped all dinosaurs from the face of the earth. But around 190 million years before the world rid itself of the prehistoric beasts, there was an even greater, lesser-known mass extinction, the name of which might send a shiver down your spine: The Great Dying.

The mass extinction is said to have killed off 90 percent of all animal life. Marine life suffered the greatest, with more than 96 percent of life lost. Living beings didn’t recover for another 10 million years. To put that in perspective, it took life in South America only 4 million years to recover after the dinosaur extinction.

William Foster, a postdoctoral researcher in the Jackson School of Geosciences who studies the time following The Great Dying, traveled to Italy to study fossils hundreds of meters below the surface to find out why it took so long for life to get back on its feet. He and his fellow researchers found that the world’s worst mass extinction was followed by two other extinction events. The results of his study were published in the scientific journal PLOS ONE on March 15.

The Great Dying is due in large part to monstrous volcanic explosions of the Siberian Traps, a large region of volcanic rock in Russia.

“What’s unique about those explosions is that these eruptions were of monumental size,” Foster says. An incomprehensible amount of what we know as greenhouse gasses (carbon dioxide, sulfur dioxide, and methane) were released, causing extreme climate warming.“Things that we worry about happening in the future happened during The Great Dying on a much much larger scale.”

There are three common hypotheses for the long recovery period. First is that the extinction was so catastrophic, life needed time to redevelop in the vacated habitat, taking five to eight million years to evolve and replace. The second is that the drastic climate change that caused The Great Dying delayed any chance of a comeback.

The third reason, which Foster’s study supported, is that there wasn’t just one extinction, but rather two more periods of elevated extinction rates. Although these extinctions didn’t have the same magnitude of loss, they compounded the damage.

Minuscule shell fossils found in Italy’s Dolomites mountain range show a period of extreme stress and loneliness for surviving organisms. Not much was left, and what did survive had to shrink in size to deal with the harsh climate change. By studying extinction events like The Great Dying, Fosters says geologists are able to better predict how climate change and climate warming will affect the world we live in today. 

“It’s unlikely that we will achieve something as catastrophic as The Great Dying in terms of climate change, however the impact of that climate warming today is similar to the climate warming back then,” Foster says. “And the complications of humans is that we also do things other than climate change to destroy the environment.”

Considering The Great Dying’s magnitude, Foster says he’s more interested in figuring out how certain species survive, not how they die. Because after all is said and done, the species born out of these extinction events make up the world we live in today.

“Our coral reefs, for example, would look very different if those extinction events didn’t happen,” Foster says. “That’s a way to look at future extinctions—something lovely will evolve in its place.”

Photo via Victor/Flickr.

 

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