Poof! The apocalypse happens, and humanity disappears. It’s a staple of science fiction and every doomsday prepper’s dread. If Earth’s abandoned places are any indication, nature would soon overtake our architectural triumphs and winding networks of roads. So if the planet’s surface reverts to a natural Eden, what human fingerprints might become buried in layers of rock for future geologists to uncover?
The usual suspects include widespread species extinctions, nuclear fallout, acidified oceans and drastic climate change. But human growth and innovation have also led people to make changes to our surroundings that are less well known—and sometimes a little bizarre. Here are six of the more intriguing ways humans are altering the planet:
Deep Holes and Shorter Mountains
Plenty of species spend their time digging. Trace evidence of subterranean burrowing even shows up in the fossil records of marine environments. But humans may have all other excavators beat. A study published in July in the journal Anthropocene argues that holes might be humanity’s most lasting impact on the planet.
While most mining projects only extend a few hundred feet into the earth, some mines for coal, precious metals and other minerals really take the plunge. Gold mines in South Africa, for instance, can reach depths of 2.5 miles. Boreholes made by oil and natural gas drilling average several thousand feet. Waste storage and underground nuclear testing will also leave an imprint on Earth’s subterranean environment. Underground transportation and sanitation infrastructure lies at shallower depths but is out of reach of erosion, so may have a modest chance of being preserved.
Human influence is also being felt at great heights. The controversial method of mountaintop mining has been practiced in the Appalachian region of the U.S. for decades. It involves blasting off the peak of a mountain or hill to reveal seams of coal beneath. And China is using similar mountaintop removal methods to make room for its rapidly growing cities. A project in Yan’an aims to double the city’s available land by removing nearby hills that are above 328 feet high—creating more than 19,000 acres of flat land. Researchers warn that such projects could come with serious geological and environmental consequences.