China and India have both achieved enormous, and vital, increases in agricultural production over the last half-century; while irrigation projects, most of which have involved drawing water from underground aquifers, have played a crucial, but unsustainable role. These practices, plus urban and industrial growth, make devastating shortages likely in the near future. Both countries are contemplating massive water diversion projects in response. Some of China’s projects are underway, while India’s remain in the planning stages. Both countries (and some of their neighbors as well) are also building giant hydro-electric dams. All of these projects converge in the Himalayas, where clean water is still relatively plentiful, and high altitudes mean that the water has great hydro-electic potential; however, the environmental risks are enormous, and because so many of the rivers beginning in Tibet cross international borders, the risk of conflict is also large. The Yalong Zangbo/Brahmaputra is the largest bone of contention, but there are many others as well. Climate-related uncertainties only intensify these risks. As the upstream country, and one with sufficient engineering and financial capabilities, China is the most powerful and independent actor in this domain; meanwhile a variety of institutional and (to a lesser extent) ideological factors have led its government to attack its water and energy problems by building enormous projects to expand water supplies, even when more decentralized approaches that emphasize conservation seem more promising. This article reviews the history behind these problems, describes the political and environmental difficulties they pose in the present, and explains some of the reasons why high-risk approaches that risk serious international conflicts are nonetheless likely to remain government favorites.