Mount Everest, the tallest mountain on Earth at 8.85 km above sea level, is 15 to 50 meters higher than it would normally be because a river erodes rock and soil at its base, helping to push of upwards, according to new research.

Landmass loss in the Arun River catchment, 75km away, is raising the world’s already highest peak by up to 2mm a year, University College London (UCL) researchers told the BBCE.

“It’s a bit like throwing a load off a ship,” study co-author Adam Smith told the BBC. “The ship gets lighter so it floats a little higher.”

Pressure from the collision of the Indian and Eurasian plates 40-50 million years ago formed the Himalayas, and the “mechanism” of plate tectonics remains the main reason Everest… continues to rise.

But the water network of the River Arun is a contributing factor to the uplift of the mountains, the UCL team said.

As the Arun flows through the Himalayas, it removes material – the river bed in this case – from the Earth’s crust. This reduces the force on the mantle (the next layer below the crust), resulting in an upward thrust.

The research, published in Nature Geoscience, adds that this upward thrust force causes Everest and other nearby peaks to move upwards.

However, some geologists not involved in the study said the theory was plausible, but there was much in the research that was still uncertain.

Everest is located on the border between China and Nepal and its northern part is on the Chinese side. The Arun River flows from Tibet to Nepal and then merges with two other rivers to become the Kozhi, which then enters northern India to meet the Ganges.

Everest is the highest peak of the Himalayan mountain range and its summit, the highest point on Earth above sea level, at an altitude of 8,848.86 meters, and is located on the border of Nepal and China.