A Greenpeace campaigner holds sand in her hands in the Dunhuang Yangguan National Nature Reserve. The forest was planted in 1953 to protect Dunhuang City against destructive elements of the Kumutage Desert. The desert is expanding because the local Shule River holds less water, losing its grip on its banks and giving sand a chance to roam free. Increased population, agriculture and climate change have created a problem of desertification.