Guardian: Up close, the sound of global warming at the face of the Urumqi No1 Glacier is a simple, steady drip, drip, drip. Just 30 metres from the main wall, the flood of meltwater becomes so powerful that it cuts a tunnel under the floor of grey ice, leaving only a blotchy, wafer-thin crust on the surface. Compared with the collapse of ice shelves in the Antarctic, the melting of the mountains in China’s far west is one of the less spectacular phenomena of global warming, but it is a more …