Most dinosaur-loving students today remember the BBC's 1999 Walking with the Dinosaurs. Everyone knows this story: the incredible creatures roamed the Earth millions of years ago but were tragically — and wholly — obliterated in a massive meteor impact.
But even the most hard-core dinosaur lovers are often shocked to hear that the mass extinction that marked the end of the dinosaurs, between the Cretaceous and the Tertiary periods (the K-T mass extinction), was nothing compared to the “Great Dying.” The Great Dying, also known as the "end Permian extinction," was the mass extinction that marked the end of the Permian period and the beginning of the Triassic period 252 million years ago. It was an extinction event so massive that it took the earth about 10 million years to recuperate.
Western University professor Cameron Tsujita and Earth sciences graduate student Jordan Siewnarine are both keen to shed some light on this mystery. Tsujita specializes in post-mortem processes and paleoecology. Siewarine is an ocean detective — trying to reconstruct what the sea would have been like in the Silurian period between 443.8 and 419.2 million years ago.
So how is it that the Great Dying was more destructive than a meteor almost 15 kilometres wide hitting the Earth? And what could be more catastrophic than eradicating all dinosaurs (except birds, of course)? Both Siewnarine and Tsujita tell the same story.
Arguably the most offensive part of the whole article. pic.twitter.com/OQQ3JGbcnh— Kiersten Formoso (@Formorphology) April 4, 2019
“It’s the greatest extinction event on the planet. Ninety-six per cent of species went extinct at the end of that time period. Something ridiculous like close to 98 per cent of sea-faring species and 70 per cent of land-going species went extinct,” Siewnarine explains.
Around 96 per cent of species is a lot of species — and a lot more than the amount that died during the K-T mass extinction.
“In that extinction [of the dinosaurs], only about 74 to 75 per cent of species went extinct on earth," says Siewnarine. "A change of 20 per cent is ridiculous — if 20 per cent of species went extinct today, that is already enough to call it a [mass] extinction event.”
So what caused this extinction? Well, as it turns out, that’s still up for scientific debate, but a few main theories have arisen.
“The end Permian extinction from my knowledge can be classified into two theories and a middle ground. There was the instantaneous event — [large meteors] and massive volcanism. And the other theory, the gradual event, they hint towards sea anoxia [a lack of oxygen in the water] and a gradual process that eliminated species that way,” Siewnarine explains.
Because the crust of the ocean is constantly recycled, conclusive evidence of meteor impacts that could have caused this mass extinction are probably long gone. Nonetheless, there is one piece of evidence too strong to be ignored.
“So this was something called the Siberian Traps, and it was one of the largest volcanic outputs ... in the known history of the planet.… The Siberian Traps was 1.5 million [square kilometers of lava]... Imagine a lava field the size of Texas. That’s what happened in a sort of short geologic time frame,” Siewnarine explains.
However, a lava field the size of Texas is not enough to cause an extinction event that massive. The effects of these massive eruptions is what caused the long-lasting damage that changed the fate of the earth as we know it.
“[Volcanism causes] all these bad elements to be released into the environment like sulfate, carbon dioxide, causing a runaway global warming effect. This causes a rise in temperatures globally, and once that happens, all these domino effects happen,” Siewnarine explains.
These “domino effects” include anoxic and acidic oceans. Anoxia is often caused by increasing temperature — like how a cold beer has more bubbles than a warm one. Acidic oceans mean that shelled creatures can no longer make their shells, as these shells are made of minerals easily dissolved by acid.
"[A lot of shellfish are] filter feeders, so they don’t use photosynthesis, but they are a food item for a lot of animals. If you cut oxygen to the ocean,... you starve the food web and cause a collapse,” Siewnarine explains.
This sounds eerily similar to climate change warnings today; greenhouse gases like carbon dioxide cause these destructive domino effects like ocean warming, anoxia and acid rain. Although the effects that humans have aren't even close to the magnitude of the Great Dying, Tsujita, like other scientists around the world, believes that we are in the midst of another mass extinction.
“Today, we are losing huge number of species over a relatively short period of time,” he explains. "If we make a rough estimate of that, the number of species that we have lost in the last 20 years would still be above the normal rates of extinction. So by definition, we are still dealing with a mass extinction.”
As Tsujita warns, only the generalists survive mass extinctions. Tsujita describes a species specialized to its environment as a “canary in a coal mine,” and when we start to see these species die off, like pandas and polar bears, this is a warning that the most specialized creature of all, humans, should heed.
“We should take pause at that and think that that is one of the reasons why they are particularly vulnerable is that they are so specialized. It’s the specialists that go first.” says Tsujita.
After all this, you might be feeling like every day is doomsday. But even Tsujita describes himself as a "long-term optimist," and Siewnarine keeps his head up, too.
“I’m an optimistic guy to the end of time. Humans have the ability to change things around… Once large scale companies realize this — we are feeling [the effects of climate change] now with the collapse of agriculture and the collapse of certain industries — once that paradigm shift happens, there may be a huge push toward fixing this.”