Himalayan glaciers, often called the third pole are losing their ice fast. According to a new comprehensive international study, Himalayan glaciers across India, China, Nepal and Bhutan have been losing the equivalent of more than a vertical foot and a half of ice each year since 2000.
The study, published in Science Advances journal claims, the Himalayas lose an average of 4 billion tonne ice from 1975-2000. After 2000, however, the glaciers started melting twice as fast, losing about 8 billion tonnes, every year up to 2016. That much ice can fill 3.2 million Olympic-sized swimming pools. The analysis, spanning 40 years of satellite observations, indicates that melting of the Himalayan glaciers caused by rising temperatures has accelerated dramatically.
Some researchers have argued that factors other than temperature are affecting the glaciers. These include changes in precipitation, which seems to be declining in some areas (which would tend to reduce the ice), but increasing in others (which would tend to build it). Also, another factor is Asian nations are burning ever-greater loads of fossil fuels and biomass, sending soot into the sky. Much of it eventually lands on snowy glacier surfaces, where it absorbs solar energy and hastens melting.
While not specifically calculated in the study, the glaciers may have lost as much as a quarter of their enormous mass over the last four decades, said lead author Joshua Maurer, a Ph.D. candidate at Columbia University’s Lamont-Doherty Earth Observatory.
The spy satellite photographs used in the research had lain unused in archives for some years. But a computer tool developed by Maurer and colleagues enabled these 1970s photos to be turned into 3D maps. The scientists used this data to track the changes in 650 Himalayan glaciers. On average, the glacier surfaces sank by 22cm (8.6 inches) a year from 1975 to 2000. But the melting has accelerated, with an average loss of 43cm a year from 2000 to 2016.
Prof Joerg Schaefer, also at Columbia and part of the team, said: “It is really the doubling of the speed of glacier melt that is most concerning.” The new understanding of past melting means forecasts can now be made with far more confidence but the outlook is dire, he said. “It looks devastating and there is no doubt in my mind, not a single grain of doubt, that [the impact of the climate crisis] is what we are seeing.”
Many other recent studies have suggested that the glaciers are wasting, including the one projecting that up to two-thirds of the current ice cover could be gone by 2100.
Melting glaciers will affect great rivers that flow through China, India, Pakistan, and Bangladesh. This, in turn, will have a serious impact for billions depending on these rivers in recent future.