Environmental Science

Himalayan Glacial Melt is 6.5% Underestimated

Himalayan Glacial Melt is 6.5% Underestimated

For the first time, scientists have provided documentation of the mass loss of Himalayan glaciers, which had previously gone unnoticed since it was taking place below the glacier’s surface. It is estimated that the glaciers have lost 570 million elephants’ worth of mass.

Due to satellites’ inability to observe glacier changes occurring underwater, the lake-terminating glaciers have been underestimated. Previous studies could not account for this loss since the satellite data used can only measure the lake’s surface and not the underwater ice that has been replaced by water.

Previous assessments found that the total mass loss of lake-terminating glaciers in the greater Himalayas was 6.5 percent, according to researchers from the UK’s University of St Andrews, the Chinese Academy of Sciences, Graz University of Technology in Austria, and Carnegie Mellon University.

According to a study that was published in the journal Nature Geoscience, the central Himalayas, where glacial lake expansion has been the fastest, saw the greatest underestimate.

According to the study’s authors, their estimations “reduce uncertainties in total glacier mass loss, provide critical information for glacial-hydrological models, and thus also support the management of water resources in this vulnerable mountain region.” With a high underestimate of 65%, the example of Galong Co in this region is particularly intriguing.

The significance of these discoveries for comprehending the effects of local water supplies and glacial lake outburst floods cannot be overstated. According to lead author Guoqing Zhang from the Institute of Tibetan Plateau Research, “By accounting for the mass loss from lake-terminating glaciers, we can more accurately assess the specific annual mass balance of these glaciers compared to land-terminating ones, which further highlights the accelerated glacier mass loss across the greater Himalaya.

From 2000 to 2020, proglacial lakes in the region increased by 47 percent in number, 33 percent in the area, and 42 percent in volume. This expansion resulted in an estimated glacier mass loss of around 2.7 Gt equivalent to 570 million elephants or over 1000 times the total number of elephants living in the world.

Researchers emphasized the need of understanding the mechanisms underlying glacier mass loss, as well as the worldwide underestimated mass loss of lake-terminating glaciers.

“In the long run, we expect mass loss from lake-terminating glaciers to continue being a major contributor to total mass loss throughout the twenty-first century, as glaciers with significant mass loss may disappear more rapidly than existing projections,” Carnegie Mellon University co-author David Rounce said.