“The Great Dying” –Our Evolving Sequel May Be More Like Science Fiction Than Anything in Earth’s History

 

“There was forest-destroying acid rain and a landscape so barren that rivers had stopped winding. There were carbon dioxide levels so high, and global warming so intense, that much of the earth had become too hot even for insects.”

“It was literally a singular event in Earth history — a monster,” said MIT’s Seth Burgess, of the event 250 million years ago known as the Great Dying, when life on Earth collapsed in spectacular and unprecedented fashion, as more than 96 percent of marine species and 70 percent of land species disappeared in a geological blink of an eye writes Peter Brannen in The Ends of Worlds, “from armor-clad trilobites in the oceans to giant reptiles on land. The host of strange creatures vanished, giving way to the ancestors of modern flora and fauna.”

The so-called end-Permian mass extinction ­remains the most severe extinction event in Earth’s history.

A new 2018 MIT study reports that in the approximately 30,000 years leading up to the end-Permian extinction, there is no geologic evidence of species starting to die out. The researchers also found no signs of any big swings in ocean temperature or dramatic fluxes of carbon dioxide in the atmosphere. When ocean and land species did die out, they did so en masse, over a period that was geologically instantaneous.

“We can say for sure that there were no initial pulses of extinction coming in,” says study co-author Jahandar Ramezani, a research scientist in MIT’s Department of Earth, Atmospheric, and Planetary Sciences. “A vibrant marine ecosystem was continuing until the very end of Permian, and then bang—life disappears. And the big outcome of this paper is that we don’t see early warning signals of the extinction. Everything happened geologically very fast.”

 

What Caused ‘The Great Dying’ –“70 percent of Earth’s Land Species Disappeared in a Geological Instant” (MIT)

The emerging sixth mass extinction—the Anthropocene one that seven billion humans are triggering is shaping up to be like nothing our planet has ever seen is more a story of Volvos vs Volcanoes. That’s the conclusion of a sweeping new analysis, which compared marine fossil records from Earth’s five previous mass extinction events to what’s happening in the oceans right now.

What remains the same however throughout our planet’s history of apocalyptic extinctions it the culprit: the dramatic increase in carbon dioxide in the atmosphere.

“Basically the entire global economy rests on how quickly we can get carbon out of the ground and put it in the atmosphere,” says UC Irvine geoscientist and climate modeler Andy Ridgwell about the modern project of civilization. “That’s basically the global enterprise. And there’s a lot of people doing it. Geologically, it’s a really impressive effort.”

Today we humans emit a mind-boggling 40 gigatons of carbon dioxide a year, perhaps the fastest rate of any period in the last 300 million years of earth history—a period that includes the End-Permian mass extinction.

Burning every last oily drop and anthracite chunk of fossil fuel on earth would release roughly 5,000 gigatons of carbon to the atmosphere. If we do so, the planet will become unrecognizable, with huge swaths rendered uninhabitably hot for mammals like us (to say nothing of the more than 200 feet of sea level rise that would drown much of civilization).

But as exceptional as humans are, estimates of the carbon released in the End-Permian mass extinction range from an utterly catastrophic 10,000 gigatons of carbon—twice as much as we could ever burn—up to a mind-meltingly unfathomable 48,000 gigatons according to Brannen. As a result, temperature estimates for the End-Permian mass extinction and its aftermath strain belief.

In the Permian Karoo Desert, writes Brannen, “as rivers stopped winding, insects stopped buzzing, and mass death swept over the land, the temperature might have jumped as much as 16 degrees Celsius. On Pangaea, 140-degree-Fahrenheit heat waves wouldn’t have been unusual. In the tropics, ocean temperatures skyrocketed from 25 degrees Celsius—similar to today’s oceans—to perhaps upwards of 40 degrees Celsius (104 degrees Fahrenheit).”

“Big changes in temperature come right after the extinction, when the ocean gets really hot and uncomfortable,” Ramezani of the MIT research says. “So we can rule out that ocean temperature was a driver of the extinction.”

So what could have caused the sudden, global wipeout?

The leading hypothesis is that the end-Permian extinction was caused by massive volcanic eruptions that spewed more than 4 million cubic kilometers of lava over what is now known as the Siberian Traps, in Siberia, Russia. Such immense and sustained eruptions likely released huge amounts of sulfur dioxide and carbon dioxide into the air, heating the atmosphere and acidifying the oceans.

Prior research by MIT’s Sam Bowring and his former graduate student Seth Burgess determined that the timing of the Siberian Traps eruptions matches the timing of the end-Permian extinction. But according to the team’s new data from the Penglaitan section, even though increased global volcanic activity dominated the last 400,000 years of the Permian, it doesn’t appear that there were any dramatic die-outs of marine species or any significant changes in ocean temperature and atmospheric carbon in the 30,000 years leading up to the main extinction.

Bowring uses high-precision U-Pb geochronology to reconstruct the history of the Earth in deep time, from the formation of the planet’s earliest crust to the time scales of major biotic radiation and extinction events.

“We can say there was extensive volcanic activity before and after the extinction, which could have caused some environmental stress and ecologic instability. But the global ecologic collapse came with a sudden blow, and we cannot see its smoking gun in the sediments that record extinction,” Ramezani says.

“The key in this paper is the abruptness of the extinction. Any hypothesis that says the extinction was caused by gradual environmental change during the late Permian—all those slow processes, we can rule out. It looks like a sudden punch comes in, and we’re still trying to figure out what it meant and what exactly caused it.”

“This study adds very much to the growing evidence that Earth’s major extinction events occur on very short timescales, geologically speaking,” says Jonathan Payne, professor of geological sciences and biology at Stanford University, who was not involved in the research.

“It is even possible that the main pulse of Permian extinction occurred in just a few centuries. If it turns out to reflect an environmental tipping point within a longer interval of ongoing environmental change, that should make us particularly concerned about potential parallels to global change happening in the world around us right now.”

So what might we speculate could happen after the geological doomsday switch is thrown?

When the planet heats up carbon dioxide reacts with seawater to make it more acidic, robbing oceans of carbonate. Since many marine species rely on narrow pH ranges and an abundance of carbonate to build their skeletons, and rapidly infusing the ocean with a deluge of carbon dioxide can be lethal.

Today the pH of the modern ocean is falling fast, reports Brannen, already by a staggering 30 percent since the start of the Industrial Revolution. Even people unmoved by the galaxy of evidence for global warming have no rebuttal to ocean acidification. It’s simple chemistry.

Most frightening for our world, it was ocean acidification that Stanford University paleontologist Jonathan Payne thinks was the most important kill mechanism in an End-Permian ocean in which, rounding up, roughly everything died.

For the last few million years, CO2 levels on the planet have swung between around 200 parts per million during the ice ages and about 280 parts per million during much warmer times, which is where the planet was before the Industrial Revolution and during all of human civilization before it, which took place during a remarkably stable Holocene climate window.

Environmental activist Bill McKibben says that beyond 350 parts per million is forbidden territory, completely outside of human experience. When the world shockingly hit 400 parts per million in 2013, scientists around the globe reacted with horror: this global chemistry experiment, if left unchecked, will almost certainly threaten the stability of civilization.

The last time carbon dioxide hit 400 parts per million, sea level eventually rose 50 feet higher than today.

“So taking the modern ocean and adding 40,000 gigatons of carbon—like in the End-Permian—it would take you from, say, 300 ppm to 30,000 ppm CO2,” Payne said.

Author Peter Brannen asked Penn State’s renowned paleoclimatologist Lee Kump whether comparisons to the modern day are really appropriate. “Well, the rate at which we’re injecting CO2 into the atmosphere today, according to our best estimates, is ten times faster than it was during the End-Permian. And rates matter. So today we’re creating a very difficult environment for life to adapt, and we’re imposing that change maybe ten times faster than the worst events in Earth’s history.”

Then, Brannen’s interview with Kump turned truly scary.

“Let me tell you about my latest horror movie concept,” Kump said. “The people out at the National Center for Atmospheric Research [NCAR] have these fancy models that can run through the daily cycle and through the annual cycle, and with Permian conditions they’ve been generating hypercanes.”

Hypercanes are continent-sized hurricanes-from-hell, explains Brannen, “with 500-mile-per-hour winds, that surprisingly pop up in atmospheric models whenever ocean temperatures are ramped up into uncharted territory. Like seawater hotter than 100 degrees Fahrenheit, 500-mile-per-hour winds are almost inconceivable.

“These are mega-hurricanes,” continues Kump, “which can penetrate clear up to the Arctic Circle—hugely powerful. They cover, you know, the entire continent. So they’re so huge—just incredible expanses—and they have great power to penetrate onto land. And so, one of the things I’ve been trying to get the people at the NCAR to do is to have one of those cross an ocean in which there’s hydrogen sulfide, because the hypercanes are going to suck it up. So you’d have these hurricanes, that not only have these 500-mile-per-hour winds, but that are loaded with hydrogen sulfide and carbon dioxide.”

To summarize the end-Permian past with an eye to a science-fiction Earthly future, Brannen concludes in The End of Worlds: ‘There was an ocean that was rapidly acidifying—one that, over huge swaths of the planet, was as hot as a Jacuzzi and completely bereft of oxygen. There were sickly tides suffused with so much carbon dioxide and hydrogen sulfide that either poison would have sufficed as a killer in its own right. There was a Russian landscape detonating and being smothered in lava several miles deep. There was a fog of neurotoxins and lethal smog streaming from these volcanoes and, high above, an ozone layer blasted apart by halocarbons, inviting a bath of lethal radiation at the planet’s surface.

“There was forest-destroying acid rain and a landscape so barren that rivers had stopped winding. There were carbon dioxide levels so high, and global warming so intense, that much of the earth had become too hot even for insects.

“And now there were Kump’s unearthly  mega-hurricanes, made of poison swamp gas, that would have towered into the heavens and obliterated whole continents.”

The Daily Galaxy via The Ends of Worlds and MIT

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