Mount Everest is the world's highest mountain above sea level (Credit :Nara.getarchive.net/ Public Domain)

Mount Everest, Earth's highest peak, is growing faster than expected. Recent GPS measurements indicate it is adding up to 2 millimeters annually. This is nearly twice the previously estimated rate. This growth is mainly due to the collision of the Indian and Eurasian tectonic plates over the past 50 million years. However, a new study by the China University of Geosciences suggests that a river capture event may also be helping the growth of the 29,032-foot (8,849-meter) mountain.

A river capture event occurs when one river changes its course and steals water from another. In this case, the culprit is the Arun River that lies about 47 miles (75 km) east of Mt. Everest. The scientists believe it diverted water from a river flowing north of Mt. Everest around 89,000 years ago. They are not sure what led to the capture event. But they suspect it began with a major flood that redirected water into the Arun River.

The extra water in the Arun River increased erosion along its banks. Over time, a lot of soil and rocks were washed away. This created a deep gorge. With less weight pressing down on Earth's crust, the ground under Mt. Everest and nearby areas started to rise. This process is called isostatic rebound.

The scientists estimate that this river capture has added between 49 to 164 feet (15 to 50 meters) to Mt. Everest's height over the past 89,000 years. They predict this growth will continue for millions of years. The extra height will further challenge climbers trying to climb the already formidable mountain.

“The biggest impact is probably on the climbers that have to climb another 20 meters (65 feet) or so to the top," said study co-author Matthew Fox.

A view from the summit of Mount Everest (Credit: Carlos Pauner/ Own work/ CC-BY-SA-3.0/ Wikimedia.org)

But not all scientists are convinced by the study's findings. Mike Searle, a geologist and professor at Oxford University, says that river capture events are fairly common. He asserts that it is difficult to link them to land elevation. This is especially true when they occur far from the area as is the case here.

“The main arguments are geographical,” Searle told The Washington Post. “River incision, in my opinion, has little to do with mountain uplift.”

Resources: Washingtonpost.com, CNN.com, Smithsonianmag.com