Everest is about 15 to 50 meters higher than it would be because of uplift caused by a nearby gorge being eroded by a river, a new study by UCL researchers finds.
The study, published in Nature Geoscience, found that erosion from a network of rivers about 75 kilometers from Everest is carving a major canyon.
With the loss of this land the mountain is rising up to 2 millimeters a year and has already grown from 15 to 50 meters in the last 89.000 years.
With a height of 8.849 meters, Everest, known as Chomolungma in Tibet or Sagarmāthā in Nepal, is the highest mountain on Earth with the Himalayas as its highest peak. Everest is considered unusually high for a mountain range, as the next three highest peaks (—K2, Kangchenjunga and Lhotse) all differ by about 120 meters from each other.
A significant part of this anomaly can be explained by an uplift force caused by pressure beneath the Earth's crust after a nearby river eroded rocks and soil. It's a phenomenon called isostatic rebound, where a portion of the Earth's crust that is losing mass bends and "floats" upward because the intense pressure of the liquid mantle below is greater than the downward force of gravity after the loss of mass.
This is a gradual process (usually the mountain rises a few millimeters a year), but over geological time frames it can make a significant difference to the Earth's surface.
The researchers found that due to this process, Everest has risen by about 15 to 50 meters over the past 89.000 years, since the nearby Arun River merged with the adjacent network of Kosi rivers.
The study's co-author, a Ph.D. Adam Smith (UCL Earth Sciences) reported:
“Everest is a remarkable mountain of myth and legend, and it is still growing. Our research shows that as the nearby river system digs deeper, the loss of material causes the mountain to rise further."
doi.org/10.5281/zenodo.13208960
