Erosion threatens the height of Mount Everest

Researchers believe that a combination of geological factors and the effects of erosion could cause a mountain higher than Everest to appear in the future.

Mount Everest is the world's tallest mountain above sea level . But to determine whether this will last forever, we must first understand how mountains are formed and why Mount Everest and the rest of the Himalayas are so tall. One way mountains form is when two tectonic plates collide. As one plate begins to sink or move beneath the other, the Earth's crust is pushed up and becomes a mountain.

The height of mountains formed by such collisions depends on a number of factors, according to Rob Butler, a geologist at the University of Aberdeen in Scotland. These include the thickness of the Earth's crust, which is determined by the intensity and length of the tectonic collision, and the temperature of the crust, which is determined by its age.

Everest is the highest mountain in the world today with a height of 8,849m.

"Imagine the Earth's crust not as a solid, but as an oily liquid like maple syrup. Like cold syrup, cold crust is more oily and therefore more solid. So a cold, thick crust builds higher mountains than a warm, thin crust," Butler explains.

Aside from the thickness and temperature of the Earth's crust, the most important factor determining the height and growth of mountains is erosion . According to Butler, the effects of erosion are so effective that the Himalayas are one of the fastest rising rock systems on the planet . This is based on the principle of isostasy. Similar to a container ship floating on the ocean, the less material piled up on the Earth's crust, the higher it rises above the mantle (the middle layer of the planet).

So the more material is carried away from the mountain, whether through rivers, glaciers, or heavy rains and landslides, the higher the surrounding mountains rise. In fact, a 2024 study found that rapid erosion by a river system more than 72 kilometers from Mount Everest has helped the peak rise 15 to 50 meters in the past 89,000 years.

While erosion is a factor in mountain growth, it is also a factor in mountain shrinkage , according to Matthew Fox, a geologist at the University of London. Whether a mountain grows or shrinks depends on the balance between the rate of erosion and the rate of elevation. If the rate of elevation is greater, the mountain grows. If the rate of erosion is greater, the mountain shrinks.

Some scientists believe that Nanga Parbat, one of Everest's Himalayan neighbors and the ninth-tallest mountain on Earth, is growing fast enough to surpass Everest in height in the future. Butler is not sure, however. While Nanga Parbat is growing faster than Everest, it is eroding faster due to the region's rainfall intensity . Everest, on the other hand, is growing and eroding more slowly, leaving it only 610m taller than Nanga Parbat.

Still, Butler doesn't rule out the possibility that another Himalayan peak could usurp Everest's position. Regardless of whether there are fluctuations over time, factors that cause peak growth rates to change. But Butler says the likelihood of a peak much taller than Everest is slim. Plus, on Earth, gravity is too strong for mountains to grow much higher than Everest's current height.