To gauge the change in glacier volume, the scientists created a method to ‘essentially do what our eyes do naturally’, using overlapping images to construct a three-dimensional image of the terrain.
The satellite data spans India, China, Nepal and Bhutan. Each of those countries, in addition to Afghanistan, Bangladesh, Myanmar and Pakistan, are members of the Kathmandu-based International Centre for Integrated Mountain Development (ICIMOD), which has been studying the changes now underway in mountain glaciers.
ICIMOD released an assessment earlier this year stating that, in a best-case scenario, Himalayan glaciers will lose more than one-third of their mass by the end of the century. And if greenhouse gas emissions continue at current rates, two-thirds could be gone.
That melting could have devastating consequences for communities in and near the Himalaya, many of whom already face poverty and malnutrition. Glacier melt adds to those vulnerabilities, threatening floods, landslides and the loss of their water supply.
“With glacier melt, the impact is biggest for mountain communities who are directly dependent on glaciers,” said ICIMOD’s David Molden.
Communities that rely on Himalayan glaciers for water already see the effects of shrinking ice, Molden said. As canals that channel glacier water to communities run dry, they have to dig new ones, higher in the mountains. “You can look at the mountain and kind of see these stripes of canals hitting the glacier,” Molden said.
Researchers hope their findings can create a framework that will help communities adapt to potential changes and hardships as temperatures continue to warm. “What does that change actually mean in terms of downstream water resources? We can give some sense of projections to communities.”
Molden said the spy satellite findings could be important in helping to persuade policymakers to plan for the effects of climate change: “It’s strengthening the case that climate change is coming more rapidly than we expect.”