Mass Extinctions: Now Easier Than Ever to Trigger!
Image credit: AJC1 via Flickr/CC BY
The mass extinctions that wracked the earth 200,000 years ago may have been much easier to trigger than was previously believed, a new study published in the July issue of Science argues. It was thought that it took 600,000 years to suffocate much of the planet's life with carbon dioxide. But scientists now have evidence that just a few thousand years of warming temperatures were enough to spur a massive release of methane from the world's seafloors -- creating a feedback loop that dramatically altered the Earth's climate, and rendered it inhospitable for many living things.
And so, the inevitable million-dollar question: Does this finding have any connection to the modern day climate crisis? In a word: Absolutely. Here's Ars Technica:
"Scientists have been worried about the current release of methane from seafloors. What this study shows is that it already happened in the past," said paleoecologist Micha Ruhl of Utrecht University, whose findings are published July 21 in Science. "It could happen again. It's only the boundary conditions that we don't know."The paper goes on to describe how radically the resultant heat changed life on Earth -- think palm trees in the North Pole and crocodiles swimming around in the Arctic. Seriously.
In what scientists call the end-Triassic mass extinction, at least half of all living species simply disappear from the fossil record. The die-off didn't merely cause ecological disruption. It was so sudden and profound that planetary chemical cycles went haywire for the next several million years ...
Scientists have raised the possibility that rising global temperatures could release trapped methane into the atmosphere, further raising temperatures and releasing more methane in a feedback loop of warming and planetary disruption. That's apparently what happened during the end-Triassic extinction.
Now, the possibility that continued planetary warming will tip off various "feedback loops" has long been studied by scientists -- melting of permafrost, the release of seafloor methane, and the disappearing ice cover in the Arctic are all major concerns. And physicist and climate writer Joe Romm has long warned that the Earth's climate system is an "ornery beast" that responds dramatically to even incremental changes.
But this new evidence is a powerful reminder that we humanfolk are in the midst of running a dangerous experiment with the planet's climate -- and that it is indeed possible that we may well trigger a feedback loop that changes (and exterminates much of) life on the planet as we know it. Sounds hyperbolic, but as this paper points out: It has happened before.
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