For Tenzin Dorje, the road home keeps getting longer. Each year the Tibetan shepherd must walk farther to find streams where his sheep can drink.
“I am an old man,” he says, clutching the neck of his cane. Sometimes he trudges six hours a day, twice his old route. He has contemplated learning to ride a motorbike like his grandson, but fears it might be too discomfiting for an 80-year-old man.
The problem is that streams in the province of western China where he lives are drying up, receding into the mountains.
As recent years have brought higher temperatures and altered how snowmelt trickles down from glaciers on the Tibetan-Qinghai plateau, water is becoming scarce.
Mr. Tenzin lives in a small village nestled amid dramatic mountains peaks. Strings of Tibetan prayer flags flap against a still-brilliant blue sky. Yet this apparent purity and timelessness masks another reality: He is living on the frontier of
Tenzin’s village is on the slopes of the rugged Qilian mountains in western Gansu province. Glaciers on the mountains are the primary source of water for humans, farms, and industry in his village of Baijiaowan and for others north and south of the range.
The streams distinguish the landscape, including a string of oasis towns along the Old Silk Road, from the abutting Gobi Desert. Today, the desert is expanding.
“The climate is changing,”says Zhang Mingquan, a professor of earth and environmental sciences at Lanzhou University, in the provincial capital. “Snow is the source of the stream water, and now the stream water is less than before.”
Recent years have seen higher temperatures and less precipitation. As a result, mountaintop ice is receding.
The Chinese Academy of Social Sci ences estimates that the glacial area on the Tibetan-Qinghai plateau, the world’s largest ice sheets outside the poles, is shrinking about 7 percent each year.
It might seem that melting glaciers would bring more water in the short term. But that isn’t necessarily the case, says Michael MacCracken of the Climate Institute in Washington.