The Biggest Killer in the History of Earth, Revealed

Scientists think they've fingered the single most prolific killer in the history of Earth.

First, let's contextualize the killer's work. We think history's greatest murderers, we think Dahmer, Gacy, the Zodiac. Napoleon, Genghis Khan. The Nazis, colonialism. The Black Death. Famine, drought. A steamy carbon-saturated atmosphere. That giant asteroid that snuffed out the dinosaurs. But the biggest killer ever was behind the Permian extinction event: what otherwise buttoned-up scientists call the Great Dying, when, 250 million years ago, 96 percent of life on earth was snuffed out.

The perpetrator behind the Great Dying left the planet a fetid ruin, with little more than a few insects, giant crocodiles, and a pig-faced mammal called the lystrosaurus crawling around. The precise cause of Earth's greatest extinction event, however, has remained shrouded in conjecture. Over the last few decades, scientists have rounded up a number of the usual suspects: climate change, a comet impact, the breaking apart of the supercontinent Pangea.

They'd also blamed a mega-volcano eruption—the Siberian Traps, a truly spectacular, million-year long loosing of magma which not only launched volcanic gases into the atmosphere, but may have boiled enough carbon-rich rocks to release billions of tons of greenhouse gases, too. And that's looking increasingly like the culprit.

New research from MIT geochronologists, presented at an American Geophysical Union conference, heaps some heavy evidence that volcanoes were indeed the planet's greatest killer.

Live Science's Besky Ostin writes that "Thanks to new computer models of the eruption's devastating effects, and detailed mapping of rocks deposited around the time of the mass dying, researchers now have their best case ever for pinning the extinction on the enormous lava outpouring."

The AGU reports that the scientists "re-analyzed uranium and lead isotope ratios in zircon crystals from south China, and found striking differences in the age of these previously studied samples." With an "improved technique for radioisotope analysis," they were able to more accurately date the volcanic rock—and show the Traps began erupting tens of thousands of years before everything on the planet started to die.

"We can resolve the timing of the Siberian Traps and show that magmatism did precede the onset of mass extinction," Seth Burgess, an MIT geochemistry graduate student involved in the research said, according to Live Science.

Scientists still aren't sure what kind of geologic conditions were in place to beget such a massive magmatic outpouring, but it seems increasingly likely that volcanoes are the most violent killers in geohistory. Which should interest us pink-bodied surface dwellers, whose dreams of the apocalypse mostly revolve around disease, robots, nuclear holocaust, industrial global warming, and alien invasions these days. But our greatest killer is neither fantastical nor manmade, and eventually, it's going to kill again.