The Planet Has Seen Sudden Warming Before. It Wiped Out Almost Everything.

[riversedge]

The Planet Has Seen Sudden Warming Before. It Wiped Out Almost Everything.



https://www.nytimes.com/2018/12/07/science/climate-change-mass-extinction.html

In some ways, the planet's worst mass extinction — 250 million years ago, at the end of the Permian Period — may parallel climate change today.



Dec. 7, 2018

Some 252 million years ago, Earth almost died.

In the oceans, 96 percent of all species became extinct. It’s harder to determine how many terrestrial species vanished, but the loss was comparable.

This mass extinction, at the end of the Permian Period, was the worst in the planet’s history, and it happened over a few thousand years at most — the blink of a geological eye.

On Thursday, a team of scientists offered a detailed accounting of how marine life was wiped out during the Permian-Triassic mass extinction. Global warming robbed the oceans of oxygen, they say, putting many species under so much stress that they died off.

And we may be repeating the process, the scientists warn. If so, then climate change is “solidly in the category of a catastrophic extinction event,” said Curtis Deutsch, an earth scientist at the University of Washington and co-author of the new study, published in the journal Science.



Researchers have long known the general outlines of Permian-Triassic cataclysm. Just before the extinctions, volcanoes in what is now Siberia erupted on a tremendous scale. The magma and lava that they belched forth produced huge amounts of carbon dioxide.

Once in the atmosphere, the gas trapped heat. Researchers estimate that the surface of the ocean warmed by about 18 degrees Fahrenheit. Some researchers argue that the heat alone killed off many species.
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Fossilized crinoids, marine invertebrates that lived during the Permian Period, found in western Australia. Scientists say the Great Dying, which wiped out 96 percent of all life in the oceans, was caused by global warming, which deprived the oceans of oxygen.CreditCreditJohn Cancalosi, via Getty Images

[Loki Liesmith]

1. This is way more warming than we will see fwiw

[NickB79]

2. Depends on the timeframe

Over the next century, sure, we'll just warm 4 degrees or so. That will be enough to cause a large portion of our global civilization to collapse (think Somalia and Syria).

But climate change doesn't just stop in the year 2100. If the Arctic thaws enough, the buried carbon and methane starts to release. Then the frozen methane hydrates start to thaw. Within a few hundred years, you could be looking at 10 degrees of warming, which starts getting disturbingly close to the Permian period.

THEN you have to figure on humanity doing its own fair share of extinction initiation through our farming, deforestation, overfishing and mineral extraction to desperately support our civilization and capitalist economy just a little bit longer.

Put together, and we may be looking at something like the Cretaceous dieoff, when we "only" lost 75% of all species.

[hatrack]

3. True . . . .

We would do well to dispense with thinking in terms of centuries, or human generations, and starting thinking a bit more geologically.

[Loki Liesmith]

4. Methane effect is difficult to quantify

Recent methane releases have been largely offset by methanovores(see Deepwater Horizon scenario). The hope would be that such bacteria would eat the excess and mitigate the gas’ effect. Admittedly that’s a hope but to my knowledge this is not well modeled either way.

Of course none of this doesn’t mean we aren’t going to have massively engineer the atmosphere post 2100. Don’t see a way around that at this point.