From the moment life arose on our planet, death trailed close behind. During the Permian mass extinction 250 million years ago, it almost caught up. They don’t call it the “Great Dying” for nothing — 95 percent of marine species and three-quarters of land species perished, as the largest volcanic eruptions in history fueled a devastating period of climate change that many researchers compare to global warming today.
The extinction that wiped out the dinosaurs draws more attention, but it’s no match for the Permian, the third major mass extinction of the Big Five. This cataclysm was by far the most desperate time for life on Earth. And, in contrast to many extinctions, most scientists agree on its main cause: “Volcanism has pretty clearly emerged as the robust answer,” says Paul Renne, a geophysicist at the University of California, Berkeley.
Evidence for this theory comes from the Siberian Traps in Russia, a vast field of lava flows left over from intense volcanic activity near the end of the Permian period. Altogether, the layers of magma cover more than half a million cubic miles — or enough to bury the entire world to a depth of around 20 feet. They aren’t the product of some ancient Mount St. Helens or Krakatoa, though. “These eruptions are very, very different,” Renne says. “They’re a lot more like Hawaii. They’re really just flows that creep over large areas.”
In the 1990s, Renne and his colleagues were the first to date the Siberian Traps, matching them almost perfectly to the fossil record for the extinction. Since then, more analysis has refined that chronology, bolstering the link between the most voluminous volcanism since complex life first emerged and the most profound die-off of all time.
