On a warm summer afternoon, Jia Son has hiked a mile and a half up the gorge that Mingyong Glacier has carved into sacred Mount Kawagebo, looming 22,113 feet high in the clouds above. There's no sign of ice, just a river roiling with silt-laden melt. For more than a century, ever since its tongue lapped at the edge of Mingyong village, the glacier has retreated like a dying serpent recoiling into its lair. Its pace has accelerated over the past decade, to more than a football field every year—a distinctly unglacial rate for an ancient ice mass.
"This all used to be ice ten years ago," Jia Son says, as he scrambles across the scree and brush. He points out a yak trail etched into the slope some 200 feet above the valley bottom. "The glacier sometimes used to cover that trail, so we had to lead our animals over the ice to get to the upper meadows."
Around a bend in the river, the glacier's snout finally comes into view: It's a deathly shade of black, permeated with pulverized rock and dirt. The water from this ice, once so pure it served in rituals as a symbol of Buddha himself, is now too loaded with sediment for the villagers to drink. For nearly a mile the glacier's once smooth surface is ragged and cratered like the skin of a leper. There are glimpses of blue-green ice within the fissures, but the cracks themselves signal trouble. "The beast is sick and wasting away," Jia Son says. "If our sacred glacier cannot survive, how can we?"
It is a question that echoes around the globe, but nowhere more urgently than across the vast swath of Asia that draws its water from the "roof of the world." This geologic colossus—the highest and largest plateau on the planet, ringed by its tallest mountains—covers an area greater than western Europe, at an average altitude of more than two miles. With nearly 37,000 glaciers on the Chinese side alone, the Tibetan Plateau and its surrounding arc of mountains contain the largest volume of ice outside the polar regions. This ice gives birth to Asia's largest and most legendary rivers, from the Yangtze and the Yellow to the Mekong and the Ganges—rivers that over the course of history have nurtured civilizations, inspired religions, and sustained ecosystems. Today they are lifelines for some of Asia's most densely settled areas, from the arid plains of Pakistan to the thirsty metropolises of northern China 3,000 miles away. All told, some two billion people in more than a dozen countries—nearly a third of the world's population—depend on rivers fed by the snow and ice of the plateau region.