How high Mt. Everest is?

Any general knowledge buff will tell you that Mount Everest, straddling the border between China and Nepal, stands at precisely 8,848m, or 29,029ft, above sea level.

Except that this is not necessarily so.

The Nepalese and Chinese governments have agreed to disagree on its height after negotiations in Kathmandu this week over a question that has fascinated and frustrated cartographers for more than 150 years.

Nepal will continue to say that the world’s highest peak is 8,848m, based on an Indian survey in 1955 that measured it from the top of its cap.

China, meanwhile, will use a new figure of 8,844.43m, calculated in 2005 by its State Bureau of Surveying and Mapping, which measured the height of the rock beneath the layers of snow and ice.

The two countries agreed to recognise each other’s figures and to acknowledge that they measured different things. Nepal, however, is still refusing to accept a figure of 8,850m that was calculated by an American expedition in 1999 using satellite positioning for the first time, and is now used by the US National Geographic Society.

Nor does the controversy end there. Many scientists believe that the mountain is becoming up to 4mm higher every year as the Indian sub-continent pushes into the rest of the Asian continent. Rising sea levels attributed to global warming are also confusing traditional methods of estimating sea level — the base from which the height of Everest and all other points on land are measured.

The debate over Everest’s height has been going on since the peak was identified in the Great Trigonometrical Survey of India that began in 1802 and lasted most of the 19th century.

Andrew Waugh, the British Surveyor-General of India, was the first to note in 1847 that there appeared to be a peak even taller than Mount Kanchenjunga, in Sikkim — until then considered the world’s highest. He was unable to take an accurate theodolite reading, however, because Nepal would not allow British surveyors to enter.

In 1852 a young Indian mathematician called Radhanath Sickdhar became the first person to calculate the height of the mountain — then named Peak XV — at 8,840m. In 1856, after averaging out several readings,Waugh publicly declared that the mountain was “most probably the highest in the world”.

At the same time he sparked another controversy by proposing to name the mountain after his predecessor as Surveyor-General, Sir George Everest.

Everest opposed the idea because he said that local people could not pronounce his name but the Royal Geographic Society approved it in 1865 on the ground that there were too many different local names.