Burning Fossil Fuels Almost Ended All Life on Earth

“Who you with?”

“I’m a science journalist,” I said, jolted from my reverie on the shoulder of I-68 in Maryland, where a crowd of geologists had gathered on a field trip to poke at some rocks revealed by the highway department’s dynamite. The rocks, slate gray and studded with pebbles from a punishing ice age, spoke to a mysterious global die-off at the end of the Devonian period, hundreds of millions of years ago.

“I’m researching a book on mass extinctions,” I said.

“Cool, I work on the end-Permian boundary in Wyoming.”

My ears perked up. He was talking about a line in the rocks that recorded the greatest catastrophe the Earth has endured in its entire history.

“I didn’t really realize there was a—”

“Let’s go out there. Want to go out next week?”

This was my introduction to Jonathan Knapp, a PhD candidate at West Virginia University. The surprisingly bold introductory exchange, I would later learn, was not atypical for Knapp, for whom there are no half measures. A week later I was in his passenger seat on a road trip across the country to Wyoming to see the worst thing that’s ever happened in person: the end-Permian mass extinction.

Imagine you took a random spin in a time machine and ended up in the Permian. Now imagine the time machine breaks down. You slam your fists on the dashboard and a digital red “251.9 MYA” dimly flickers and dies. The view out the cockpit window reveals red sand dunes and little else. From what you remember of your geology training you know that 252 million years ago is just about the worst thing you could possibly read on your display.

You kick the door open and—holy hell is it hot. You scarcely believe your breath. As you reach for the latch to slam it shut you’re startled by a thundering roar coming from the other side of the dunes. Curious, you step out into the primeval landscape. There’s no life, save a wilting weed here or there, where the dunes give way to barren soils, cracked and crusted with salt. The sandblasted husk of some odd creature sprawls across the wastes, its fangs bared.

A sole mayfly buzzes in and out of your sight—its presence in this desolate wilderness is comforting. Scrambling over the red sand, and gasping for air, you follow the distant roar. You notice that, though the sun is out, there’s a funereal