Team remeasures height of Mt. Everest to settle debate

BEIJING — Most seasoned mountain climbers’ bucket lists include Qomolangma, known in the West as Mount Everest, as they are often motivated by the thrill of reaching the world’s highest peak.

But for Khim Lal Gautam, Nepal’s chief surveyor and leader of the first Nepali government-appointed team to measure Qomolangma, climbing the mountain is a source of pride.

Gautam’s team went on a monthlong expedition in April to remeasure the height of Qomolangma, which is more than 8,000 meters above sea level. This was meant to settle the debate in the international geological community on whether the mountain shrank after a magnitude 7.8 earthquake devastated Nepal in April 2015.

Gautam welcomed the Department of Survey’s decision to entrust him with a “historic, important and challenging job”.

Qomolangma “is the highest peak in the world, so (its altitude) is of interest to the whole world as well”, he said.

Gautam’s team has sent the data they collected to the department for processing. The results are expected to be out by next year.

The team’s attempt to measure Qomolangma this time was particularly challenging. Gautam said the spring season was not particularly good for climbing since there is only a very short period of suitable weather. The team also had to stay at the summit for more than an hour since they had to set up equipment and collect data.

He said staying at the summit for extended periods is not advisable, and most mountaineers prefer to descend as soon as possible.

Many climbers suffer from lack of oxygen, or hypoxia, if they stay on the summit too long.

Gautam said the team also had to work at night so they would not be disturbed by other climbers. This posed an additional problem since it was colder at night.

“The whole mission was fraught with challenges. Fortunately we managed them all,” he said.

Mahar Lagmay, a professor at the University of the Philippines’ National Institute of Geological Sciences, said that the 2015 earthquake would definitely have changed Qomolangma’s elevation because the temblor forced the underlying tectonic plates to collide.

Qomolangma is in the Himalayan range, which was formed millions of years ago after the Indo­Australian plate collided with the Eurasian plate. The collision pushed Earth’s crust up and formed mountains. These tectonic plates continue to move, and geologists estimate that Qomolangma is growing by a few centimeters each year.

However, that conventional knowledge was challenged after the 2015 earthquake.

In April 2015, four days after the deadly earthquake in Nepal, data from Europe’s Sentinel­1A satellite showed that a broad swath of ground near Kathmandu, the Nepali capital, had been lifted vertically by about a meter, according to a report by online news site Live Science.

However, UNAVCO, a geoscience research consortium based in Colorado in the United States, interpreted these images and estimated that Qomolangma’s height had actually dropped by about 2.5 centimeters because Earth’s crust relaxed after the earthquake, releasing pent­up strain.

Kul Bahadur Gurung, general secretary of the Nepal Mountaineering Association, said the association lobbied for the Nepali government to remeasure Qomolangma to clear any confusion.

Gurung said mountaineers need to be updated on the latest developments in Qomolangma’s measurements, since this will affect the logistics of mountain climbing.

Nepal started its project to measure the peak in December 2017 when the Department of Survey conducted a workshop on the methods to be used in remeasuring Qomolangma.

In 2018, a technical team from the department went to the eastern Nepali district of Solukhumbu to do precise leveling work, Xinhua News Agency reported.