By Louisa Lim
BBC News, Beijing
China is to re-measure the world's tallest peak, Mount Everest, because of fears it may be shrinking.
This is not the first time Everest's height has triggered arguments
A recent survey found the summit had dropped by 1.3 metres (4 ft) because of global warming.
The height of the mountain, which lies on the border between China and Nepal, has long been a subject of controversy.
It was first measured in the 1850s, but a more accurate Indian survey 100 years later calculated the mountain to be 8,848m tall.
In 1999, American scientists re-measured the mountain using global positioning satellite technology.
They - and the National Geographic Society - concluded that the peak was two metres higher.
But now global warming is melting glaciers on the world's highest mountain, apparently causing it to shrink.
Chinese scientists will map Everest in March to check estimates that it is more than a metre shorter than before.
No matter how big it really is, Mount Everest's height is unlikely to stay constant.
The movement of the earth's tectonic plates is forcing the Himalayas upwards, reportedly causing Everest to grow by about a centimetre every year.