This is how a glacier retreats. At nearly 4,000 meters above sea level, in the shadow of a sharp Himalayan peak, a wall of black ice oozes in the sunshine. A tumbling stone breaks the silence of the mountains, or water gurgles under the ground, a sign that the, glacier is melting from inside.

Half a century after Mao Zedong’s “Great Leap Forward” brought irrigation to the arid grasslands in this remote corner of northwest China, the government is giving up on its attempt to make a breadbasket out of what has increasingly become a stretch of scrub and sand dunes.

Scientists are looking at the potential for rapid climate change to create droughts. Droughts have affected all areas of the world, and could become more common.