"Like generations of Tibetan nomads before him, Phuntsok Dorje makes a living raising yaks and other livestock on the vast alpine grasslands that provide a thatch on the roof of the world.
But in recent years the vegetation around his home, the Tibetan plateau, has been destroyed by rising temperatures, excess livestock and plagues of insects and rodents.
The high-altitude meadows are rarely mentioned in discussions of global warming, but the changes to this ground have a profound impact on Tibetan politics and the world's ecological security.
For Phuntsok Dorje, the issue is more down to earth. He is used to dramatically shifting cloudscapes above his head, but it is the changes below his feet that make him uneasy."