NEW DELHI — Sharpening Asian competition over energy resources, driven in part by high growth rates in gross domestic product and in part by mercantilist attempts to lock up supplies, has obscured another danger: Water shortages in much of Asia are beginning to threaten rapid economic modernization, prompting the building of upstream projects on international rivers. If water geopolitics were to spur interstate tensions through reduced water flows to neighboring states, the Asian renaissance could stall.

Water has emerged as a key issue that could determine whether Asia is headed toward mutually beneficial cooperation or deleterious interstate competition. No country could influence that direction more than China, which controls the Tibetan plateau — the source of most major rivers of Asia.

Tibet's vast glaciers and high altitude have endowed it with the world's greatest river systems. Its river waters are a lifeline to the world's two most-populous states — China and India — as well as to Bangladesh, Myanmar, Bhutan, Nepal, Cambodia, Pakistan, Laos, Thailand and Vietnam. These countries make up 47 percent of the global population.