Small debris-free plateau glacier with glacier lakes at Gangrinchemzoe Pass at 5,200 m, south of the main Himalayan divide, Bhutan. Photo via USGS
In case you were convinced otherwise by the quasi-scandal of 'Himalayagate' earlier in the year: The US Geological Survey has released a new report on the state of glacier retreat in the Himalaya and it makes perfectly clear the situation, "Many of Asia's glaciers are retreating as a result of climate change. This retreat impacts water supplies to millions of people, increases the likelihood of outburst floods that threaten life and property in nearby areas, and contributes to sea level rise."
Indian Glaciers Show Marked Retreat in Past Two Decades
Looking at glaciers throughout South and Central Asia, and working with nearly 40 international scientists, the report points out that the rate at which glaciers are retreating varies. Bhutan's 66 glaciers have retreated 8.1% in the past 30 years. In the Indian Himalaya melting has been more pronounced, with the Chhota Shigri Glacier retreating 12% in the past 13 years and the iconic Gangotri Glacier, where the River Ganga originates, retreating 12% in the past 16 years.
Separate recent reports note that beyond rising average global temperatures, black carbon soot from diesel engines and other industrial processes falling on Himalayan glaciers is responsible for up to 90% of the melting in the region. Though not technically a greenhouse gas, this particulate air pollution is increasingly being cited as a significant cause of warming temperatures, glacier melting, and changing weather patterns.
Advancing Glaciers Caused by Unique Local Conditions
Addressing the fact that while most Himalayan glaciers are retreating, some continue to advance, the report notes, "Some of the advancing glaciers are surge-type glaciers, which move forward more rapidly than average in a short period of time...likely due to unique and local conditions."
Melting Glaciers Threatens Water Supply & Lives For Tens of Millions of People
As for the impacts, the report treads likely familiar ground for most TreeHugger readers but the potential severity of the situation bears repeating:
"Of particular interest are the Himalaya, where glacier behavior impacts the quality of life of tens of millions of people," said USGS scientist Jane Ferrigno. "Glaciers in the Himalaya are a major source of fresh water and supply meltwater to all of the rivers in northern India."
As glaciers become smaller, water runoff decreases, which is especially important during the dry season when other water sources are limited. Climate change also brings warmer temperatures and earlier water runoff from glaciers, and this combined with spring and summer rains can result in flood conditions. The overall glacier retreat and additional melt can increase the amount of water dammed in the vicinity of a glacier, and the added pressure enhances the likelihood of disastrous outburst flooding.
Read more: Glaciers of Asia: US Geological Survey Professional Paper
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More on Glacial Melting :
90% of Himalayan Glacier Melting Caused by Aerosols & Black Carbon
Some Himalayan Glaciers are Growing. Does This Mean Global Warming Isn't Real?
Himalayan Glaciers Shrank 16% in Past 50 Years: Indian Space Research Org.
Then and Now Photographs Document Stunning Melting of Himalayan Glaciers