Just when Asia was getting accustomed to the Chinese threat to the oceans of Southeast Asia, there’s another water worry for Asians. The government in Beijing controls the health of six major South and Southeastern Asian rivers, the heart of life in the region. All of the rivers rise on the Tibetan plateau. The Chinese have been on an intensive program of dam-building on the upper reaches of the Brahmaputra, the Irrawaddy, the Meman Chao Phya and the Mekong, which would give them the ability to control these arteries of commerce, as well as irrigation of rice and other crops, for vast areas downstream.

Snows are melting on thousands of glaciers, the largest concentration of ice north and south of the poles, repeating the ancient and constant cycle of change in the world’s weather. Tibet’s glaciers have shrunk by 15 percent over the past 30 years. Though subject to the whims of climate change, if melting continues at current levels the warmer temperatures could melt two-thirds of the plateau’s glaciers by 2050, and this would affect in unknown ways 2 billion people in China, India, Pakistan, Bangladesh, Bhutan, Burma, Thailand, Laos, Cambodia and Vietnam.

The most dramatic example of prospective risk is China’s plan to divert the Brahmaputra from its upper reaches, where it flows a thousand miles through Tibet and another 600 miles through India, emptying into the harbor of Calcutta, the second-largest city of India. The Brahmaputra is the lifeline of northeast India, a troubled region with caste and other ethnic conflicts.

There's concern in Thailand, Laos, Vietnam and Cambodia over eight dams under construction on the upper reaches of the Mekong River. China’s apparent intention to dam every major river flowing out of Tibet will lead to environmental imbalance, natural disasters, degrade fragile ecologies, and most of all, divert vital water supplies.