The recent photo of a snaking queue of climbers waiting to reach the top of Mount Everest worried many, suggesting the world's highest peak was becoming another tourist trap. But the heavy traffic -- and resultant ecological damage -- might be the least of the Himalayan range's troubles.
Some of the world's most populous and fast-developing countries, notably China and India, depend on the water released from the Himalayas and nearby ranges, which feeds important rivers including the Ganges, Indus, Mekong, Yangtze, Yellow, Amu Darya, Salween, Irrawaddy and Brahmaputra. The river basins they support generate $4.3 trillion in annual GDP and over 3 billion people rely on food grown there.