[But teams from around the world, including China, Denmark, Italy, India and the United States, have come up with other calculations, which have sometimes strayed a little bit higher, or a little bit lower, than that figure. Italy, in 1992, lopped seven feet off the standard height, measuring it at 29,022 feet. In 1999, a measurement by American scientists pushed the peak a little higher, saying the mountain reached 29,035 feet.]
By
Bhadra Sharma and Kai Schultz
 |
|
The height of Mount
Everest is widely recognized as 29,029 feet. But the calculation is inexact and subject to
multiple factors.
Nepal is sending a team of surveyors to the summit to settle
the “How tall?” question for themselves. Credit
Roberto Schmidt/Agence
France-Presse — Getty Images
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KATHMANDU,
Nepal — Mount Everest is the
tallest mountain in the world, but precisely how tall is it?
It’s not such a simple question.
In the past, geologists have disagreed about
what to include in their calculations: Should the summit’s snowcap be included?
Or should surveyors drill down to the peak’s rock base?
What about the recent earthquakes in Nepal,
which geologists believe shrunk the mountain by about three centimeters, or a
little more than an inch? Or the fact that wind speed affects how much snow
covers the summit at any given time?
Then there is the challenge of geography:
Reaching the summit of Everest is only possible a few weeks each year, and
measuring the mountain’s height from sea level has presented difficulties in
the past. (Landlocked Nepal is a long way from the nearest shore.)
Today, Everest’s height is widely recognized
as 29,029 feet.
But teams from around the world, including
China, Denmark, Italy, India and the United States, have come up with other
calculations, which have sometimes strayed a little bit higher, or a little bit
lower, than that figure. Italy, in 1992, lopped seven feet off the standard
height, measuring it at 29,022 feet. In 1999, a measurement by American
scientists pushed the peak a little higher, saying the mountain reached 29,035
feet.
These measurement expeditions have typically
excluded experts from Nepal, which shares the mountain with China and is one of
the poorest countries in Asia.
Now, for the first time, Nepali surveyors are
limiting intervention from foreign powers and sending a team to the summit to
settle the height question for themselves. In addition to the science, a bit of
national pride is at stake.
“Mount Everest is our treasure,” said Buddhi
Narayan Shrestha, the former director general of Nepal’s Department of Survey.
“What will happen if foreign experts continue to reduce the height of our
mountain without us participating?”
The first recorded attempt to measure
Everest’s height came in the mid-19th century, when Nepal was a Hindu monarchy,
closed to outsiders.
A team hired by Sir George Everest, a former
surveyor general of India, assembled near India’s border with Nepal. It was
there that Radhanath Sikdar, a young Indian mathematician, and a group of
so-called human computers, used triangulation to collect data on the mountain,
known then as Peak XV.
Folklore has it that when Mr. Sikdar finished
calculating his findings in 1852, he made a beeline for the office of a
superior stationed in the foothills of the Himalayas and announced that he had
“discovered the highest mountain in the world.”
In 1856, the height of Peak XV was recorded
at 29,002 feet, a number remarkably close to the height recognized by climbing
bodies today. But Mr. Sikdar’s contributions were pushed to the footnotes, and
Peak XV was eventually renamed in honor of Mr. Everest.
About 100 years later, when Nepal cracked
open its borders to foreigners, scientists moved their measurement tools closer
to the mountain, which lies partly in Tibet. In the mid-1950s, the height was
recognized as about 29,029 feet, making it the world’s tallest mountain above
sea level.
(By one measure, the world’s highest peak is
actually Mount Chimborazo in Ecuador. The summit of Chimborazo, an inactive
volcano in the Andes, rises about 20,500 feet above sea level, far short of
Everest. But because of the globe’s bulge at the Equator, it’s a different
story when you measure from the center of Earth: Chimborazo’s apex then rises
the farthest, at about 21 million feet or 3,967 miles.)
Government officials in Nepal have been
selective about recognizing data generated by other countries, with some
measurements less welcome than others.
Take the case of China, which shares the
summit with Nepal. After Chinese surveyors assessed Everest’s summit in 2005,
measuring the height both from the peak’s rock base and from the top of the
snowfall, a heated dispute over the height ensued.
Ang Tshering Sherpa, the former head of the
Nepal Mountaineering Association, said China applied pressure on the Nepal’s
government and an international climbing body to recognize 29,017 feet, the
measurement from the rock base, as the mountain’s new height.
But Nepal held its ground, and China recently
backed down, Mr. Sherpa said, apparently in response to a drop in climbers
tackling the mountain from the Tibet side.
Having those few extra feet recognized on
summit certificates was enough for some mountaineers to switch routes, opting
to climb from, and spend money in, Nepal.
“China changed its own findings last year
after the number of climbers summiting Mount Everest from the northern side
significantly decreased,” Mr. Sherpa said.
A proposal from India to jointly measure the
mountain with Nepal was passed over. Last year, Swarna Subba Rao, then the
surveyor general of India, allocated resources to send a 30-member team of
mountaineers to gather data from the summit. Nepal, which has had frosty
relations with India in the past, “humbly declined” the proposal.
“We are capable of the job,” said Ganesh
Prasad Bhatta, the director general of Nepal’s Department of Survey, which is
overseeing Nepal’s measurement project.
Roger Bilham, a geologist at the University
of Colorado Boulder, said Everest’s location in the zone of compression between
southern Tibet and India means it sinks during earthquakes and rises in the
period between them. A major earthquake in 1934 lowered the mountain by 63
centimeters, or about two feet, according to data provided by Mr. Bilham.
In the 19th century, the height of Everest
was calculated by measuring the angles between the top of the mountain and
points on the ground whose positions relative to the average height of the sea
were already known.
Now, surveyors place a global positioning
system receiver on the summit ice for an hour, and mathematically calculate the
height of the sea from satellites and measurements of gravity at the base.
To prepare for the country’s own expedition,
Nepali surveyors will collect measurements this month along the country’s
southern plains, where they plan to calculate sea level. A team of Sherpas are
also being trained to bring a GPS receiver to the summit. The cost to measure
the mountain is estimated at $250,000.
Alan Arnette, a well-known mountaineer, said
any measurement of the summit is still “a snapshot in time,” with different
levels of ice accumulation causing variations in the height. He questioned
whether the expedition was worth what it would cost Nepal.
“As a mountaineer, I would like to see the
results,” Mr. Arnette said, “but as someone who supports the Nepal people, the
money could be spent on jobs, food, clean air and other programs more important
to the health of the nation.”
Bhadra Sharma contributed reporting from
Kathmandu, and Kai Schultz from New Delhi.
Follow Bhadra Sharma and Kai Schultz on
Twitter: @bhadrarukum and @Kai_Schultz.