Mount Everest, the world's highest mountain standing at 8.85 km above sea level, is still growing taller, according to a new study published in the journal Nature Geoscience.
While the Himalayas have been rising for approximately 50 million years due to the collision of the Indian and Eurasian tectonic plates, scientists have discovered that Everest is growing even faster than expected.
The research, led by geoscientist Jin-Gen Dai from China University of Geosciences in Beijing, reveals that a significant change in the regional river system has contributed to Everest's accelerated growth.
Approximately 89,000 years ago, the Kosi river merged with the Arun river, leading to an estimated height increase of 49-164 feet (15-50 meters) for Everest.
This phenomenon is attributed to a geological process called isostatic rebound.
As the merged rivers caused increased erosion and removed massive amounts of rock and soil from the region, the weight on the Earth's crust decreased. Consequently, the land beneath began to rise, similar to a boat rising in water when cargo is unloaded.
The study estimates that isostatic rebound accounts for about 10% of Everest's annual uplift rate, which translates to roughly 0.01-0.02 inches (0.2-0.5 millimeters) per year. This uplift outpaces the ongoing surface erosion caused by factors such as wind, rain, and river flow.
Interestingly, neighbouring peaks like Lhotse and Makalu are also experiencing similar growth due to this process. Makalu, situated closer to the Arun river, has a slightly higher uplift rate compared to Everest.
Adam Smith, a co-author of the study and doctoral student at University College London, notes that GPS measurements confirm the continued rising of Everest and the surrounding Himalayas4. As erosion persists, the uplift rate from isostatic rebound may potentially increase.
This research highlights the dynamic nature of our planet, demonstrating that even seemingly immutable features like Mount Everest are subject to ongoing geological processes. It serves as a reminder that the Earth is constantly changing, often in ways imperceptible to us in our daily lives.
