Himalayan glaciers, source of water for the innumerable rivers that flow across the Indo-Gangetic plains, are receding. And that too at a phenomenal rate. As they continue to recede, incidents of landslides, changes in river regimes and floods will increase. But only while the glaciers last. If global warming is the cause of this decline, then we can expect glaciers to disappear one day. In the long run, with large sections of these glaciers gone, the rivers will dry up. Impacts on the flora and fauna, and the 500 million people inhabiting the great Indian plain are hard to imagine. All we can conjecture today is, a few decades from now, the nation will experience a great thirst