How massive volcanoes and supercharged greenhouse gases almost wiped out life on Earth

About 250 million years ago, the world suffered through an extinction event that makes the death of the dinosaurs look like a minor hiccup by comparison. And now we have our best understanding yet of what caused the Great Dying.

We've discussed the Great Dying, otherwise known as the Permo-Triassic Extinction, before - check out this excellent backgrounder from last June for more on what happened - but exactly what caused this cataclysmic extinction event has remained unclear. But now researchers at the University of Calgary have discovered coal ash in the layer of rocks from the Great Dying, providing the first direct proof that these massive volcanic eruptions created huge coal fires.

Chief researcher Dr. Steve Grasby explains:

"This could literally be the smoking gun that explains the latest Permian extinction. Our research is the first to show direct evidence that massive volcanic eruptions - the largest the world has ever witnessed - caused massive coal combustion thus supporting models for significant generation of greenhouse gases at this time."

The likely culprits for these eruptions are the Siberian Traps, a massive range of volcanoes in far eastern Russia that covers a total landmass greater than that of Europe. These volcanoes are located beneath massive coal deposits, meaning any substantial eruption would blast huge amounts of burning coal into the atmosphere. When these volcanoes went off 250 million years ago, they set off a coal-fueled chain reaction that created huge amounts of greenhouse gases, causing runaway global warming.

Grasby says the soot and ash produced in these explosions was more or less identical to that created by modern coal power plants, although obviously on a far greater order of magnitude. He explains that greenhouse gases weren't even the only problem created by these massive eruptions:

"Our discovery provides the first direct confirmation for coal ash during this extinction as it may not have been recognized before. It was a really bad time on Earth. In addition to these volcanoes causing fires through coal, the ash it spewed was highly toxic and was released in the land and water, potentially contributing to the worst extinction event in earth history."

[Nature Geoscience; image is of Alaska's Mount Redoubt]