Researchers trekked into Siberia to find hard evidence that the Permian-Triassic extinction was the consequence of explosive volcanic eruptions and the ensuing global warming.COURTESY OF LINDY ELKINS-TANTON
Wired has an article about research into the Permian-Triassic mass extinction event, which happened about 250 million years ago. Sometimes called "The Great Dying", this event, which was really a series of events, took out about 70% of land species and more than 95% of marine species. The current theory about its cause is a runaway greenhouse driven by massive volcanic eruptions in what is now Siberia. The article is the story of Planetary scientist Lindy Elkins-Tantyon's mission to find real hard evidence to prove it.
SOME 250 MILLION years ago, the organisms of Earth were having a very bad time—the very worst time, you might say. The Permian-Triassic extinction event was unfolding, in which 70 percent of land species and 96 percent of marine species disappeared. Runaway global warming had raised equatorial ocean temperatures to 104 degrees Fahrenheit. The seas rapidly acidified, so shelled critters struggled to build their protective homes. Indeed, the fossil record shows these species got it the worst—strong evidence that the extinction’s culprit was CO2 mucking with the oceans’ pH balance, and the rest of the planet, for that matter. Every decade or so, ozone-eating gases would dissolve Earth’s protective layer in the sky, irradiating plants and animals, before the ozone layer closed up. This happened again and again, allowing periodic blasts of extreme radiation to bombard the planet.
One long-standing hypothesis for the cause of the Permian-Triassic extinction, also known as the Great Dying, will sound worryingly familiar to us modern humans: the large-scale burning of coal. Only such a catastrophe, scientists reckoned, had the power to transform Earth so radically in such a short period of time; the fossil record indicates that species weren’t dying off en masse over millions of years, or hundreds of thousands of years, but tens of thousands of years. A carbon-spewing volcanic event alone—even the biggest of booms—couldn’t explain such a cataclysm. And there’s no evidence of an asteroid strike in this period, like the one that would kill off the dinosaurs 190 million years later.
It’s a juicy theory. The only problem is that scientists didn’t have the hard evidence to prove a massive combustion of coal did all those species in. But they knew where to look: in what we now call Siberia, a frigid expanse of land that 250 million years ago was anything but chilly, because it was flooded with lava. Volcanoes pumped out so much planetary goop that the stuff could have covered the entire continental United States a half-mile deep. And unfortunately for all life on Earth, scientists suspected, the lava was flash-incinerating vast deposits of coal and ejecting massive quantities of greenhouse gases into the atmosphere.
That’s how the theory goes, anyway.