Geologic Phenomenon Making Mount Everest Grow Taller

Mount Everest , the world’s tallest mountain, is still having growth spurts.

It's been growing for millions of years and it's reached the height of 29,032 feet above sea level. But Everest is still growing upward by about 2 millimeters a year. That's according to a new study. That rate is about twice as much as experts thought. A research team published their findings in the journal Nature Geoscience. 

The reason for the fast growth is rising erosion rates, according to the study. That might seem odd since erosion is the process of slowly wearing something away. Instead of making the mountain shrink, though, the growth process called "isostatic rebound" happens. It's caused by the rerouting of water from within a network of nearby waterways.

“It’s a bit like throwing a load of cargo off a ship,” study co-author Adam Smith told the BBC. He's a University College London geoscientist. “The ship becomes lighter and so floats a little higher. Similarly, when the crust becomes lighter … it can float a little higher” atop the Earth’s mantle.

The mantle is a rock layer that lies beneath the Earth’s crust and above its outer core.

That shift likely occurred 89,000 years ago. Large swaths of the landscape around Everest began to wash away then. That's according to the study. The removal of billions of tons of rock over thousands of years has caused Everest’s growth to speed up, not the reverse. The Himalayas were first formed about 50 million years ago. That's when the Eurasian and Indian tectonic plates collided. Mount Everest straddles Nepal and Tibet in the Himalayas. 

Experts believe that Everest has grown 50 to 164 feet taller than expected in the past 89,000 years. That's why it has reached a height that’s roughly 7,260 times taller than the requirement for kids on many amusement park rides. 

Reflect: What are some ways that natural changes in our environment might impact our daily lives?

Photo of the northward of Mount Everest from Wikimedia Commons.