Earth's greatest killer finally caught, thanks to geology gumshoes (Permian mass extinction)

[NickB79]

http://www.nbcnews.com/science/earths-greatest-killer-finally-caught-thanks-geology-gumshoes-2D11741582

The eruptions — now called the Siberian Traps — lasted less than 1 million years but left behind Earth's biggest "large igneous province," a pile of lava and other volcanic rocks about 720,000 cubic miles (3 million cubic kilometers) in volume. More than 96 percent of marine creatures and 70 percent of land species perished at the end of the Permian Period, versus 85 percent of life in the later dinosaur-killer extinction. In the Permian, all trilobites died out, along with 97 percent of the gorgeous marine creatures called ammonites. Sharks, fish and reptiles were hard hit.

snip

At Penglaitan, the extinction lasted only a few thousand years, based on abundant fossil and rock evidence, Shen said. Sixty Permian species disappear in the Penglaitan extinction layer. "The end-Permian mass extinction is sudden," he said. And chemical signatures preserved in the ancient rocks indicate local temperatures jumped 14.4 to 18 degrees Fahrenheit (8 to 10 degrees Celsius) just after the extinction, an extreme warming seen in other places on the planet close to this age.

Massive carbon emissions in a very short period of time cause global mass extinction events? Who would have thunk it?

[phantom power]

1. I feel sure we can top it

[CrispyQ]

2. Some people think this mini-documentary by Thom Hartmann is alarmist.

I think it's about time we started talking the E word.

http://lasthours.org/

[tclambert]

4. Hey, chill, it's all okay. If the massive profits oil companies make causes us to go extinct . . .

well then, no one can sue them for damages afterwards. (Let's see, what's your legal liability for extincting all life on the planet? Why, it's zero!)

Hold up a moment. Does that imply the oil companies' best strategy is to deliberately push us to extinction? If their business model destroys all coastal cities, that would cost them a fortune in damages and court costs . . . but only if enough people survive to file the mother of all lawsuits. Hmmm.

[Ganja Ninja]

3. It wasn't just a carbon dioxide and global warming event.

(snip)

Other evidence of a major climatic change after the Permian die-off include sudden shifts in ratios of elements such as carbon and oxygen found worldwide. Researchers have long thought that volcanic gases from the Siberian Traps could have altered Earth's climate. Because the Siberian Traps' magma punched through sedimentary rocks such as coals and carbonates, the eruptions could have cooked the rocks, pouring extra billions of tons of greenhouse gases and toxic metals into Earth's atmosphere, according to modeling studies presented yesterday. Particles similar to fly ash from coal-fired power plants appear in lake sediments on Canada's Ellesmere Island, downwind of Siberia in the Permian, said Stephen Grasby, a geochemist at Canada's Geological Survey.

Gases such as carbon dioxide and methane warmed the Earth, and sulfur dioxide pelted the Northern Hemisphere with acid rain, researchers said. (Siberia was in the high latitudes 252 million years ago, so gases and ashes circled in the north.) "Rain in the Northern Hemisphere could have been really intensely acidic," said Benjamin Black, a postdoctoral researcher at MIT. "The pH was comparable to undiluted lemon juice."

Black created a computer model of Earth's atmosphere during the Siberian Trap eruptions, when most of Earth's landmasses were jammed together in a supercontinent called Pangaea. A giant ocean called Panthalassa covered the rest of the globe.

Just one year's worth of volcanism from the Siberian Traps, or about 57 cubic miles (240 cubic km) of lava, could generate 1.46 billion tons of sulfur dioxide and devastate the Northern Hemisphere, Black's study found. [Big Blasts: History's 10 Most Destructive Volcanoes]

The toxic gases pouring from the Earth also created chemical reactions that destroyed the protective ozone layer, raising DNA-damaging ultraviolet radiation over much of the planet, Black said. "Globally, average ozone levels fall below those observed in the Antarctic ozone hole in the 1990s," he said.

In total, more than 1,200 billion tons of methane and 4,000 billion tons of sulfur dioxide could have emerged from the Siberian Traps eruption, said Henrik Svensen, a geologist at the University of Oslo in Norway.

So there were a whole lot of other toxic gasses being expelled that contributed to the event.

[NickB79]

5. True, but a 10C warming event in a few thousand years didn't help any

Take the sulfur dioxide-induced acid rain and ozone depletion out of the mix, and you might have "only" lost what, 50-60% of all life instead of 90%?

[Spitfire of ATJ]

6. "1,200 billion tons of methane and 4,000 billion tons of sulfur dioxide"

Silent but deadly.

[NickB79]

7. Seriously though, that had to be hell on Earth

The peak of the Permian mass extinction is probably the closest this planet has ever come to resembling an actual Hell on Earth, from the descriptions I've read.

[Spitfire of ATJ]

8. It marked the end of the mammal-like reptiles and the rise of the dinosaurs too....

[LouisvilleDem]

9. Am I reading this wrong?

And chemical signatures preserved in the ancient rocks indicate local temperatures jumped 14.4 to 18 degrees Fahrenheit (8 to 10 degrees Celsius) just after the extinction, an extreme warming seen in other places on the planet close to this age.

This makes it sound like the warming is not what caused the extinctions, doesn't it?

[cprise]

10. Warming lead to anoxia

It was the lack of oxygen in the oceans that killed off most life there. Then the rotting of all that organic matter resulted in even higher temperatures.