Mount Everest, the world’s tallest peak, is now 8,848.86 m (29,031.69 ft) tall! China and Nepal jointly announced, on December 8, 2020, that the world’s tallest peak that straddles their shared border is 86 cm higher than the measurement previously recognised by Nepal (or about 3 ft higher than Nepal’s previous claim), and over 4 metres above the measurement given by China previously. Nepal until now had recognised the height of the mountain as 8,848m—the measurement given by the Survey of India in 1954—while the previous calculation by China in 2005 placed the peak at 8,844 m.
The announcement of the new height of the tallest mountain in the world marked the end of a debate between Nepal and China which had been raging for years over a ‘three-metre’ height difference. The declaring of a new height has been termed ‘an important symbol of China-Nepal friendship’.
Kathmandu and Beijing had differed over its exact height but after each sent an expedition of surveyors to the summit, they agreed that the official height was 8,848.86 metres (29,031.69 feet), a bit more than their previous calculations. Nepal, which has seven of the world’s 14 highest peaks, sent its first team of surveyors in May 2019 to measure Everest. Chinese surveyors then climbed the peak in spring 2020, when the mountain was closed by both countries for other climbers due to the COVID-19 pandemic.
Apart from the two measurements, there was one other measurement given in a survey sponsored by the National Geographic Society, US. The National Geographic Society and Boston’s Museum of Science, in 1999, determined the height of the summit as 8,850 m (29,035 feet) using satellite-based technology to measure the peak. Climbers from the West and some others use this measurement.
Nepal had never previously measured the height of Mount Everest on its own but had used the 8,848 metres (29,028 feet) estimate made by the Survey of India in 1954 that gives the ‘snow height’, i.e., the height of the summit when it is laden with snow. The Chinese measurement in 2005 determined the ‘rock height’ of the summit as 8,844.43 metres (29,017 feet), about 3.7 metres (11 feet) less than the 1954 estimate. Over the years, there have been debates on whether it should be the rock height, or whether the snow cladding it too, which should be accounted for.
It is felt that the 7.8-magnitude earthquake in Nepal in 2015, which was Nepal’s worst earthquake ever recorded that killed nearly 9,000 people, may have altered the height of the Everest. The 2015 earthquake, which occurred during the peak climbing season, triggered massive avalanches that killed 18 people at the base, halting the season’s mountaineering activities. The following year, climbers who scaled the summit said an Everest landmark, Hillary Step, a 13-metre (40 feet) near-vertical rock formation below the summit, had collapsed from the impact. But the earthquake triggered a debate among scientists on whether it had affected the height of the mountain. The Nepal government declared that it would measure the mountain on its own, instead of continuing to follow the Survey of India findings of 1954.
Mt Everest has been climbed 10,184 times by 5,789 people from both the Nepal and China sides since it was first scaled by New Zealander Edmund Hillary and Sherpa Tenzing Norgay in 1953, according to the Himalayan Database, which maintains records on climbs. At least 311 people have died on its slopes.
Earlier Measurements of the Summit
Some of the earlier recorded attempts to measure the Everest are as follows:
- 1849–55 The height of Peak XV (as Mt. Everest was called then) was determined by Andrew Waugh to be 8,839.8 m or 29,002 ft (though actually it came to 29,000 ft, two feet was added so that it did not look as if the measurement was a rounded estimate). The measurement was based on observations made from Dehradun base to Sonakhoda base, Bihar. Towers 25–30 ft tall were used with the observation stations over 150 km away in Bihar.
The inaccuracy was a result of a very high assumed value of Coefficient of Refraction at 0.08, giving no consideration for the deflection of vertical (plumb line), and other shortcomings.
- 1880–83 and 1902 A value of 8,882.2 m (29,141 ft) was obtained by Col. S.G. Burrard from Darjeeling hills in the course of a normal survey. Though the observation stations were placed higher than in the mid-1850s, the geodetic datum, a tool that is utilised to define the Earth’s size and shape, was again not defined, as in the previous one, and the vertical deflection (plumb line) again not taken into consideration.
- Starting in 1952, the Survey of India undertook an exercise to measure the height of Peak XV. That exercise measured the height at 8,848 m (29,028 feet), which was accepted by many, until now. During 1952–1954, neither GPS and satellite techniques were available nor the sophisticated gravimeters. It was finally determined in 1954, using instruments like theodolites and chains. Eight observation stations were used. It took into account factors like refraction and deflection of vertical; it also shifted the coordinates of the peak by 40 feet in the south-west direction.
Resolving the Issue
No other mountain peak has perhaps been the subject of as much debate as Mt. Everest.
Work Undertaken by the Countries The joint project had survey teams from both Nepal and China working for more than a year and finally reaching a conclusion on the snow-covered height based on the International Height Reference System (IHRS). It was for the first time that the two agreed to work on ascertaining the height of the mountain (the agreement was reached when the Chinese President Xi Jinping visited Nepal in October 2019).
New Zealand, which shares a bond with Nepal over the mountain, provided technical assistance to Nepal. In May 2019, the New Zealand government provided Nepal’s Survey Department (Napi Bibhag) with a Global Navigation Satellite, and trained technicians (a two-year training course for surveyors). Christopher Pearson, a scientist from University of Otago, travelled to Nepal on a special assignment. Involving some 300 surveyors, the work included installing a GPS on the summit and a 250-km sequence of line-of-sight stations built to triangulate an accurate height. Nepal’s Department of Survey informed that they had used various methods to ascertain the height (GPS systems, gravity data, trigonometric leveling, precise leveling) as well as the latest meteorological data. A team of 120 (field workers and data analysts) was processing the data and computing results, which took four months, when the coronavirus spread disrupted work.
China’s measurements were done with a journey to the peak on May 27, 2020, the Beijing-based Global Times reported. The project team was aided by ‘end-to-end’ 5G technology during their ascent.
The fact that both Chinese and Nepali data tallied is seen as showing the accuracy of their measurements.
Benefits of the Project
Everest, also known as Sagarmatha in Nepal and Mount Qomolangma in China, lies on the border between Nepal and Tibet. The summit can be accessed from both sides, although the Nepal route is more popular. Though the new common height is meant to end all debates, it would give China an advantage in the climbing stakes because climbing Everest through the northern side is much cheaper than climbing from the southern side (Nepal side). But so far Nepal has held the advantage.
Nepal says that its climbing side offers a more scenic view and a more adventurous experience, as opposed to China—from the Nepal side, one could drive up on a motorable road right up to the base camp. According to the Kathmandu Post, Nepal generates US $ 4 million from permits to Mt Everest alone, besides other revenues generated from climbers.
But this new height may make things difficult. Nepal’s slightly higher ‘snow height’ was a key reason why Nepal had been drawing Everest aspirants in droves. Climbers from Nepal started to swell from 2007 onwards when China started issuing Everest climbing certificates stating the height as 8,844.57 metres against 8,848 metres in certificates issued by Nepal for the same peak. Now, that advantage is done away with. Further, China is producing a lot of high-altitude climbing guides. The government trains them for at least two years. Within a few years, China may not require Nepali Sherpa climbing guides although the majority of climbing guides on the Chinese side are still Sherpas. And this is one big worry for Nepal as it would hit livelihoods.
So, for Nepal and China, the height of Everest was not merely an academic debate. It also had ramifications for a lucrative tourism industry. Beyond tourism, the end of the debate is politically symbolic of two increasingly close neighbours.
Calculating the Height
Calculating the height of any mountain peak is a difficult affair, leave alone the world’s tallest summit.
To measure the height of a tall object like a building, trigonometry is used for calculations. If the distance from the point of observation to a building is x and the angle of elevation is E, then the height of the building would be x × tan(E). This is the basic principle that is used. But when it comes to a mountain, there are problems.
The question is, from which surface one is measuring the height. For practical purposes the heights are always measured above mean sea level, as the Earth’s surface is not uniformly even at every place. This is done through a painstaking process called high-precision levelling. Starting from the coastline, step by step, the difference in height is calculated, using special instruments. This is how the height of any city from mean sea level is determined. But then this levelling cannot be done to high peaks.
Moreover, the distance to the mountain from an observation point is not easy to calculate. One cannot physically go to a mountain to calculate the direct distance (as the crow flies) from the observation point to the mountain. It seems easy today, but there were no GPS or satellite images in the 1950s.
One way is to measure the angles of elevation from two different points of observation in the same line of view. The distances between these different points of observations could then be measured. Then there would be two different triangles, but with a common arm, and two different angles of elevation. Again, by following simple rules of trigonometry, the height of the mountain could be calculated. This was the method used before use of GPS, satellites, and other modern techniques. For small hills and mountains, whose top can be observed from relatively close distances, this can give somewhat precise measurements. But for Mount Everest and other high mountains, it is not easy as the base of the mountain is not known. In other words, where exactly does the mountain meet flat ground surface. It is also not known whether the point of observation and the base of the mountain are at the same horizontal level.
Gravity varies across places, according to scientists, which means that even the sea level cannot be considered to be uniform at all places. It is argued that in the case of Mount Everest, for example, the concentration of such a huge mass means the sea level would get pulled up by gravity! So, the gravity at that point is measured to calculate the sea level at that point. Nowadays, sophisticated portable gravitometers are available that can be carried even to mountain peaks.
Another problem is that the density of air reduces as the height increases. This variation in air density causes the bending of light rays (refraction of light rays). Due to the difference in heights of the observation point and the mountain peak, refraction results in an error in measuring the vertical angle. This also has to be corrected in the measurement of the peak.
In recent years, attempts to re-measure Everest have produced results that vary by a few feet. But these have been explained in terms of geological processes that might be altering the height of Everest. Most scientists now believe that the height of Mount Everest is increasing at a very slow rate. This is because of the northward movement of the Indian tectonic plate that is pushing the surface up. It is this same process that makes this region prone to earthquakes. A big earthquake, like the one that happened in Nepal in 2015, can alter the heights of mountains.
Comparing Heights
- Helicopter typical flight altitude: 800 m (2624.67 ft) But as per www.aircraftcompare.com, helicopters typically fly at altitudes of 10,000 ft.
- Burj Khalifa, Dubai, UAE: 829.8 m (2,722 ft) As per burjkhalifa.ae, the height is 828 metres (2,716.5 feet)
- Light aircraft typical cruising altitude: 3000 m As per USA Today, light aircraft typically stick close to 3048 metres (10,000 ft).
- Mount Fuji in Japan: 3,776 m (12,388.45 ft)
- Base Camp when climbing Mt Everest: 5,364 m (17,598 ft)
- Mt Kilimanjaro, Tanzania: 5,895 m (19340 ft)
- There are two base camps to climb Mt. Everest—South base camp at 5,364m (17,598 ft) in Nepal and North base camp at 5,150m (16,900 ft) in China.
- Camp 4: 7,906 m (25,938.32 ft)
- Lhotse (Nepal/China): 8,516 m (27,940 ft)
- Kanchenjuga peak: 8,586 m (28,169 ft)
- K2 peak (the world’s second highest peak): 8,611 m (28,251 ft)
- Commercial airliners’ typical cruising altitude: 10,000 m (32,808.4 ft)
- Ruppell’s Griffon Vulture (highest flying bird recorded): around 11,277.6 m (37,000 feet)