China and Nepal jointly announced a new height for Mount Everest, putting an end to controversy surrounding the exact height of the highest point in the world.
The new official height is 8,848.86 metres, according to Chinese state media Xinhua News Agency.
The new height would be based on trigonometric and GPS measurements carried out by Nepal and China. Nepal had sent a team of surveyors to the top of the peak in May 2019, while China sent a team earlier this year.
The heights of mountains are measured with the mean sea level as the base. Nepal used the Bay of Bengal as its sea level, while China used the Yellow Sea in the eastern province of Shandong as their sea-level base.
Nepal built a network of line-of-sight stations stretching nearly 250kmto the point Everest first become visible, creating a chain of points it could measure and add together.
Surveyors from both sides also used trigonometry formulas to calculate the height of the summit. The formulas they used calculate the height of a triangle by multiplying its base with its angles.
But for accurate results someone had to be on the top most point of the mountain. Nepalese surveyors went up to the summit last year, while the Chinese surveyors went up in May, becoming the only team to reach the top in 2020.
This was the first time Nepal had independently carried out such measurements amid speculation of a possible change in height due to global warming and a 2015 earthquake.
Some geologists have suggested the major earthquake in 2015 may have had an impact on Mount Everest’s height. The 7.8 magnitude earthquake killed nearly 9,000 people in Nepal, and caused an avalanche which buried parts of the base camp at the mountain. At least 18 climbers were killed.