The researchers have closely examined 112 glaciers in the Himalayas. To get information about the hard to reach glaciers, they have analyzed temperature data and satellite images of the glaciers in combination with field observations. The analysis depicts the seasonal behavior of the glacier’s velocity; how the glaciers move over time. A glacier’s movement is ultimately crucial for its melting rate and final fate.
– The study, for the first time for all the glaciers in a Western Himalayan river basin, reveals how terrain and climatic parameters such as temperature and snowfall at different altitudes can modify or control the movement of glaciers. It means that with a reliable degree of confidence, we can comment on the kind of terrain or elevation ranges which are most critical to affect the glacier motion and melt rates, Anshuman Bhardwaj, says and continues:
– The temperature and snowfall conditions in these mountains are significantly changing in past decades due to the changing climate. This study largely contributes to the fact that, using free satellite data, glacier movements in this area can be linked to climate change.
Many parameters of climate change affect glaciers. Increasing temperatures because of global warming speeds up melting that causes sliding motion. Extreme weather events may cause glacier disasters such as glacial lake outburst floods. Also, changes in the precipitation patterns affect glaciers in terms of adding seasonal snow to their mass which eventually contributes to their movement through deformation.
Climate change with global effects
In their study, the researchers observed that the movement of the glaciers in the Western Himalayas are not only affected by the rising local temperatures. They are also significantly dependent on the winter snowfall contributed by the Western Disturbances, an extra-tropical circulation pattern originating in the Mediterranean region that brings winter rain or snow to the northwestern parts of the Indian subcontinent. Hence, the climate change is not just a local phenomenon but it has widespread global effects.
– The topographic control on glacier movement in conjunction with changing climate in this part of Himalaya is much more complex than previously concluded, the availability of satellite-based glacier velocity products as the one used in the present study can play a good role in understanding this complexity, says Lydia Sam, Post Doc of Atmospheric Science and Lead Author of the paper.
– Ice movement can tell us how a glacier is responding to climate change. Climate has already started to effect glaciers and in 20 to 30 years, if the global warming continues with the present rate, we think that the glaciers in this part of the Himalayas will show abnormal changes in their flow regime, says Anshuman Bhardwaj.
If the Himalayan glaciers melt down altogether, the consequences could be devastating. The glaciers’ total area represent approximately 50 percent of all of the glaciers outside the poles and their meltwater sustains a downstream population of more than one billion people.
– Glaciers are the largest freshwater reserves on Earth. They also regulate local climate parameters. If they vanish, we can imagine a scarcity of fresh water that we will have to face. Also, the Himalayan glaciers are even more prone to changing climate due to their latitudinal position closer to the equator, says Anshuman Bhardwaj.
The article Heterogeneity in topographic control on velocities of Western Himalayan glaciers was published in Nature Scientific Reports and among the authors were Lydia Sam, Anshuman Bhardwaj and Javier Martín-Torres from the research group of Atmospheric Science.