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The biggest mass extinction ever seen on Earth is a warning to mankind

Right now our planet is in the midst of what science says is an unprecedented rate of change, unlike anything that has been seen for tens of millions of years. Overconsumption, unsustainable practices and the release of immense amounts of greenhouse gases resulting from the combustion of fossil fuels are changing our living climate at dangerous rates, the oceans are acidifying and losing oxygen, and species die.

But this is not the first time that life on our planet has faced an epic challenge. The worst came just over 250 million years ago – before dinosaurs walked the earth – in an episode called the Permian-Triassic mass extinction, or the great death, when 90% of the life in the oceans and 70% of life on earth has disappeared.

/ Credit: CBS News

Recently, two groundbreaking studies of the Great Dying revealed that the causes of this mass extinction bear striking similarities to what is happening today. In fact, in some ways the rate of change, such as the rate of greenhouse gas emissions, is much faster today than it was 250 million years ago.

Scientists say historical episodes like this provide a timely warning to humanity of what can happen when ecosystems change too quickly for life to follow.

In fact, the evidence gathered by scientific research on the current rate of change is worrying to say the least. Carbon dioxide in the atmosphere is increasing at a rate 100 times faster than it should naturally. Our planet is warming 10 times faster than it has been in 65 million years. Our oceans are acidifying 100 times faster than they have been for at least 20 million years, and oxygen dead zones in our oceans have increased tenfold since 1950.

Given the similarities and what is at stake today, digging into the causes and impacts of the Great Dying can open a window to a dire future for our planet – and also elucidate how urgent action is needed to address it. avoid the collapse of ecosystems and society.

What led to the great death?

Digging is exactly what Professor Uwe Brand does for a living. As a geoscientist at Brock University in Canada, his job is to dig deep into Earth’s past by digging into the Earth itself, looking for clues as to what the planet looked like years ago. million years.

As such, Brand is like a crime scene investigator searching for forensic evidence to help him put the pieces of the Great Dying puzzle together, an event that predated its existence by hundreds of millions of years. Not an easy task.

For this story, CBS News interviewed Brand to help us understand how it all happened. “I call it the perfect storm,” Brand said, because, as he explains, it wasn’t a game-changing event like the asteroid that killed the dinosaurs 65 million ago. years. Instead, it was a domino effect – a series of events, all interconnected, that ultimately put a nail in the coffin.

After decades of uncertainty, two studies published around the same time shed light on how this happened. Brand was a co-author of one such study, an October 2020 article published in the journal Nature Geoscience examining the causes of Permian-Triassic mass extinction.

In the study in which Brand participated, the authors used a technique using the boron element of fossil brachiopod shells, which they found in the rocks of modern Italy, to obtain a record of the acidity of the oceans at the time of mass extinction. This, combined with data on carbon isotopes using a sophisticated model, allowed researchers to reconstruct the likely chain of events that killed almost all life on Earth 252 million years ago.

In another article published around the same time, researchers discovered a rare molecule called coronene in Italy and China that can only form when underground fossil fuel deposits are overheated. It was another clue that helped put the pieces together.

Here’s how Brand describes how the events unfolded: Over a million years, vast volcanic activity in what is now Siberia cut through cracks and crevices of sedimentary rocks, burning oil and gas fields. gas as it travels, producing the newly discovered coronene scientists.

The biggest mass extinction ever seen on Earth is a warning to mankind

Lava in the Kilauea area near Hilo, Hawaii, in 2018. Scientists believe massive volcanic activity around 250 million years ago led to widespread extinctions. / Credit: DVIDS / Hawaii National Guard

As a result, massive lava beds were created. “It would cover at least half of the United States and be at least several miles thick,” Brand said.

This process gradually released gigantic amounts of heat-trapping carbon gases at much higher levels than today. For comparison, the concentrations of carbon dioxide (CO2) during this period are estimated at a few thousand parts per million (ppm), whereas today our CO2 level, although higher than over the past 3 million years, is still significantly lower. , at 415 ppm (but increasing rapidly).

The immense amount of greenhouse gases present at the time warmed global air temperatures to levels 18 degrees Fahrenheit higher than today. Because of the impact this has had on ecosystems, it has forced land animals to adapt, move, or die quickly. Seventy percent did not.

In the ocean, atmospheric carbon dioxide has been absorbed, mixing with water and forming sulfuric acid, acidifying the seas. As a result, the coral disintegrated and the shells of the ocean creatures dissolved.

Back on earth, the warmer climate displaced vegetation and started fires. This exposed more rocks, and the erosion went into overdrive. As a result, an overabundance of nutrients poured into the oceans, initially causing an explosion of life. But then there was the inevitable death and decay, which ate up most of the vital oxygen in the ocean. Ninety percent of ocean life has died. Brand says existence was hit from all angles.

“They aren’t individual and separate causes, but they all worked together, they acted in concert, and that’s why I call it the perfect storm. You’ve been hit on this side by the weather, on this side by acidification and finally by shock -out punch came from deoxygenation. “

Learn from history

As catastrophic as the Great Dying was, scientists fear that Earth is now heading for another catastrophe. Today, the planet is warming sharply to levels not seen in over 100,000 years, the oceans are acidifying and oxygen dead zones are on the rise.

And surprisingly, Brand says the rate of release of heat-trapping greenhouse gases is now much more drastic than it was then. “Currently our emissions are 10 to 20 times higher than what happened at the end of the Permian mass extinction, which was the largest and the largest mass extinction,” he said. declared.

To save us, he says we must learn from events like the Great Dying. “You know what they say, learn from history, because if you don’t you will repeat it.”

“The way I see it is that it will happen if we don’t stop it or mitigate what we’re doing,” he said. But Brand emphasizes, “We still have time to turn the tide by moving away from burning fossil fuels.”

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