Glaciers across the Tibetan plateau are melting “at an accelerated rate,” raising concerns for harvests and river-flows in China and India, according to environmental experts.
“The majority of the glaciers across this region are in retreat,” China expert Isabel Hilton said, speaking recently at the Woodrow Wilson Center in Washington.
“The continued research on these glaciers suggests that they will be gone by 2050,” Hilton added.
...The surface area of the glacier shrinks to the point where the melt is much less."
Lester Brown, Earth Policy Institute
Tibet’s glaciers are the source of Asia’s major rivers—including the Yellow River, the Mekong, and the Ganges—said Hilton, founder and director of the London-based environmental group chinadialogue.
“And millions of people depend on [these rivers] for agriculture, for drinking water, for living.”
“We’ve taken the glaciers and the world’s water supply for granted,” Hilton said, adding that “some 15,000” glaciers are involved.
The entire Tibetan plateau is a “climate-change hot spot,” Hilton said.
Glaciers at middle levels of elevation are retreating faster than those at higher elevations, Hilton said. “It’s just bad luck that they form a substantial proportion of what’s there.”
Rising temperatures are already having an impact in Tibet, Katherine Morton, a China specialist at Australia National University, said, also speaking at the Wilson Center.
“Tibetan nomads depend upon the grasslands for their survival, and climate change is leading to historically unprecedented pressures,” Morton said.
“For example, at the source of the Yellow River at the center of the plateau, over a third of the grasslands have transformed into semi-desert conditions.”
Since 2000, approximately 700,000 Tibetan nomads may have been resettled across the plateau, Morton said, adding that this government-directed migration “is reinforcing existing patterns of inequality.”
“Without an education and the new skills necessary to secure alternative employment, nomads can find themselves alienated from their modern surroundings.”
Source of concern
Speaking in a separate interview, Washington-based Earth Policy Institute director Lester Brown said, “The glaciers on the Tibetan plateau are melting fast.”
“The Chinese claim they may be melting at 7 percent a year,” Brown added. “The reason we’re concerned is that the ice melt from these glaciers sustains the major rivers and irrigation systems of Asia during the dry season.”
Eighty percent of China’s grain harvest, and about 60 percent of India’s, comes from irrigated land, Brown said.
Though the Ganges and Yellow River may someday come to flow only in the rainy season, glacial melt will lead at first to an increase in river flows, he said.
“Because as the glaciers start to shrink, you get more water. But after a point, the surface area of the glacier shrinks to the point where the melt is much less.”
River flows would then “just keep dropping during the dry season until they went down to almost nothing,” Brown said.
“[All] we know now is that the glaciers in the Himalayas and on the Tibetan plateau are melting, and they are melting at an accelerated rate,” Brown said.
Reported in Washington by Richard Finney. Edited for the Web by Sarah Jackson-Han.