Glacial melt plays its most vital role before and after the rainy season, when it supplies a greater portion of the flow
in every river from the Yangtze (which irrigates more than half of China's rice) to the Ganges and the Indus (key to
the agricultural heartlands of India and Pakistan).
But over the past half century, the balance has been lost, perhaps irrevocably. Of the 680 glaciers Chinese scientists
monitor closely on the Tibetan Plateau, 95 percent are shedding more ice than they're adding, with the heaviest
losses on its southern and eastern edges.
The more dark areas that are exposed by melting, the more sunlight is absorbed than reflected, causing temperatures
to rise faster. (Some climatologists believe this warming feedback loop could intensify the Asian monsoon,
triggering more violent storms and flooding in places such as Bangladesh and Myanmar.) If current trends hold,
Chinese scientists believe that 40 percent of the plateau's glaciers could disappear by 2050. "Full-scale glacier
shrinkage is inevitable," says Yao Tandong, a glaciologist at China's Institute of Tibetan Plateau Research. "And it
will lead to ecological catastrophe."
The potential impacts extend far beyond the glaciers. On the Tibetan Plateau, especially its dry northern flank
people are already affected by a warmer climate.
This situation—too much water, too little water—captures, in miniature, the trajectory of the overall crisis.
Along with acute water and electricity shortages, experts predict a plunge in food production, widespread migration
in the face of ecological changes, even conflicts between Asian powers.
But nothing compares to the campaign in China, which has
less water than Canada but 40 times more people. In the
vast desert in the Xinjiang region, just north of the Tibetan Plateau,
China aims to build 59 reservoirs to capture and
save glacial runoff. Across Tibet, artillery batteries have been installed to launch rain-inducing silver iodide into the
clouds. In Qinghai the government is blocking off degraded grasslands in hopes they can be nurtured back to health.
In areas where grasslands have already turned to scrub desert, bales of wire fencing are rolled out over the last
remnants of plant life to prevent them from blowing away.
Delhi's water demand already exceeds supply by more than 300 million gallons a day, a shortfall worsened by
inequitable distribution and a leaky infrastructure that loses an estimated 40 percent of the water. More than two-
thirds of the city's water is pulled from the Yamuna and the Ganges, rivers fed by Himalayan ice. If that ice
disappears, the future will almost certainly be worse. "We are facing an unsustainable situation," says Diwan Singh,
a Delhi environmental activist. "Soon—not in thirty years but in five to ten—there will be an exodus because of the
lack of water."
The tension already seethes. In the clogged alleyway around one of Nehru Camp's last functioning taps, which run
for one hour a day,
a man punches a woman who cut in line, leaving a purple welt on her face. "We wake up every
morning fighting over water," says Kamal Bhate, a local astrologer watching the melee.