Climate change threatens Tibetan plateau

The Qinghai-Tibetan Plateau is Earth's third largest store of ice after the South and North poles. But that store is rapidly melting amid the onset of climate change. It will affect the water supply for up to a billion people and the atmospheric circulation for more than half the planet. Xie Zheng, meets the people living on the plateau and enduring its changes.

Life as a herdsman at more than 45-hundred meters above sea level does not carry lofty expectations. You don't have to always count the number of sheep in the herd, and it almost certainly grows year-by-year.

There is always more grass than the livestock could consume, and there is minimal risk of infectious diseases at this altitude.

But all that is changing.

Continuous expansion of water is rapidly shrinking the land for livestock. The Serling Tso Lake was joined by another lake to form what is -- at 16-hundred square kilometers -- the second largest body of water in Tibet.

Buga, village head of Nagqu Prefecture, Tibet, said, "My family has been living by the lake since my grandfather. The lake has always been expanding, but not as dramatically as since the late 1980s. In 2001, the local government set up a two-meter high pole to measure the increase of the water level. Now, even the pole itself is underwater. If you ride a motorcycle for 18 kilometers in width and 50 kilometers in length, that will be the grassland consumed by the expanding water."

A bird's eye-view of the lake from the highest nearby hill shows that a tiny spot in the water is all that remains of a village headquarters just a few years ago.