Declassified spy images aren’t usually evidence of climate change. But researchers at the U used recently released spy satellite photos of Himalayan glaciers from the cold war to track the rate of ice melt over the last 50 years. And what they found was alarming. The water supply for 800 million people has been losing about a vertical foot and a half of ice each year since 2000. That’s about double the amount of melting that took place from 1975 to 2000.
Other studies have monitored this loss, but up until now, the studies have been fragmented and focused on shorter time periods or individual regions. This new study takes a comprehensive look at the region and found that yearly losses have averaged about 8 billion tons of water, or the equivalent of 3.2 million Olympic-size swimming pools. “Until now, we didn’t know how much glacier ice, or water storage, has been lost over this period of significant and accelerating warming,” says Summer Rupper, associate professor of geography at the U and coauthor of the study about the glaciers.
The study analyzed repeat satellite images of some 650 glaciers spanning 2,000 kilometers. They found that meltwater lakes are building rapidly behind natural dams of rocky debris and are threatening downstream communities with potentially destructive and deadly outburst floods. And on Mount Everest, long-lost corpses of climbers who failed to return are emerging from melting ice and snow along trails.
The study shows that “even glaciers in the highest mountains of the world are responding to global air temperature increases driven by the combustion of fossil fuels,” says Joseph Shea, a glacial geographer at the University of Northern British Columbia who was not involved in the study. “In the long term, this will lead to changes in the timing and magnitude of streamflow in a heavily populated region.”
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