Mount Everest, the tallest mountain in the world, continues to increase yearly. Referred to as Chomolungma in Tibetan and Sagarmatha in Nepali, it emerged around 50 million years ago, following the collision between the Indian subcontinent and the Eurasian tectonic plate.
Experts indicate that Mount Everest, standing at 8,849 meters (29,032 feet), is experiencing a growth spurt. They believe this increase has surpassed initial expectations.
What accounts for the recent growth of Mount Everest? Let’s explore.
What we know
A study released in the journal Nature Geoscience on Monday, September 30, indicates that Mount Everest has increased in height by 15 to 50 meters over the past 89,000 years.
The statement indicates that the process is ongoing, with Everest expanding by approximately 2 millimetres annually, in contrast to the anticipated yearly increase of 1 millimetre.
“Everest is a fantastic mountain of myth and legend, and it continues to grow,” said study co-author Adam Smith, a PhD student in the Department of Earth Sciences at University College London (UCL).
Jin-Gen Dai, a geoscientist from the China University of Geosciences in Beijing and the study’s author, states that Everest, which rises approximately 250 meters above the other highest peaks of the Himalayas, is an anomaly.
“Although mountains may appear motionless from the perspective of human life, they are constantly in motion,” he said, according to the New York Times (NYT).
Reasons for Everest’s rapid growth.
Mount Everest, located on the border between Nepal and China’s Tibet Autonomous Region, is rising due to “piracy” or “river grabbing”.
Approximately 89,000 years ago, the Kosi River in the Himalayas diverted a section of its tributary, the Arun River, now located north of Mount Everest. Matthew Fox, a geologist at UCL and co-author of the study, explained to The Washington Post that this uncommon phenomenon, known as a “river capture event,” occurs when a river alters its path, intersects with another river, and appropriates its water.
Researchers state that merging the two rivers increased river erosion near Everest, resulting in the removal of significant amounts of rock and soil. This process contributed to the formation of the Arun River gorge.
“The Everest region has some interesting river systems,” said Dai, one of the study’s authors.
As the Arun River merged with the Kosi River system, both rivers became increasingly erosive, causing the rocky mass to erode. Over thousands of years, the Arun River carried away billions of tons of sediment and soil from its banks, shaping the vast gorge.
The removal of large volumes of sediment resulted in the uplift of the surrounding land, a phenomenon referred to as isostatic rebound.
“Isometric rebound can be likened to a floating body adjusting its position when its weight is removed,” Reuters news agency quoted geologist Day as saying.
“When a heavy load, such as ice or eroded rock, is removed from the Earth’s crust, the land underneath slowly rises in response, just like a ship rises to the surface when it is unloaded,” he added.
The researchers state that isostatic rebound contributes to approximately 10 per cent of Everest’s annual uplift rate.
Why it is important
The authors of the study state that the rebound has also impacted other Himalayan peaks, including Lhotse and Makalu, the fourth and fifth highest peaks in the world, respectively, both of which have experienced a similar uplift.
Researchers believe Makalu near the Arun River would receive an even more significant boost.
“These effects will not be permanent. The process will continue until the river system reaches a new state of equilibrium,” Dye told the Guardian.
“This research underscores the dynamic nature of our planet,” he told Reuters. “Even a seemingly static feature like Mount Everest is subject to ongoing geological processes, reminding us that the Earth is constantly changing, often in ways imperceptible to our daily lives.”
Climbing Everest is undoubtedly a daunting challenge. As the summit increases in height each year, reaching the top may become even more difficult, as the additional elevation could lead to more ice accumulation at higher altitudes. Fox, a study co-author, informed The Washington Post that “the biggest impact is likely on the climbers who must ascend an extra 20 meters or so to reach the summit.” In an interview with The Guardian, Professor Mikaël Attal from the University of Edinburgh, who was not involved in the study, remarked that while river capture is a recognized phenomenon, it occurs relatively infrequently.
The unique aspect of this study is the demonstration that erosion caused by river capture can result in a significant response of the Earth’s surface, with an area equivalent to the size of Greater London rising by several tens of meters throughout tens of thousands of years, which is relatively rapid.
However, only some people are persuaded by the study’s findings. Geologist Mike Searle, who did not participate in the research, informed The Washington Post that while river capture is frequent in areas near active mountain ranges, establishing a connection to uplift is challenging, mainly when it occurs several kilometres away.
Fox reportedly stated that tectonics and the loss of mountain glaciers are other factors that explain the uplift.
