The Himalayan glaciers are of paramount importance in the Indian context, especially for the millions of people living downstream who rely on these perennial rivers for their daily water needs. They are rapidly receding under the effects of global warming, and suffocating pressure on water resources is inevitable in the coming decades. In contrast, the central Karakoram glaciers have surprisingly remained unchanged or grown slightly over the past few decades. This phenomenon baffled glaciology and provided climate deniers with a very rare straw to grasp at.Researchers have taken a major step toward solving the mystery of why few pockets of glaciers in the Karakoram Mountains are resisting glacier melt due to global warming, bucking the trend of glaciers losing mass across the globe, the Himalayas being no exception. They attribute this phenomenon, called the “Karakoram Anomaly”, to the recent resurgence of Western Disturbances (WD).
Dr. Pankaj Kumar, an associate professor at the Indian Institute of Science Education and Research (IISER) Bhopal, found this strange because the behavior appears to be confined to a very small area, with only the Kunlun mountain range being another example showing similar trends across the Himalayas. A recent study conducted under his supervision proposed a new theory to explain this resistance to the effects of global warming in certain pockets unlike other glaciers in the region.In a paper published , his group argued that the recent resurgence of western disturbances was instrumental in triggering and sustaining the Karakoram anomaly since the turn of the 21st century. The study was supported by the Climate Change Program of the Institute of Science and Technology.
This is the first time that a study has pointed to the importance that the increased input of WD precipitation during the accumulation period plays in modulating the regional climate anomaly.AaquibJaved, Ph.D. student Dr. Kumara and lead author of the study said, “WDs are the primary source of snow in the region during winter. Our study suggests that they account for about 65% of total seasonal snowfall and about 53% of total seasonal precipitation, easily making them the most important source of moisture. The intensity of WD precipitation impacting the Karakoram has increased by approximately 10% over the past two decades, which only reinforces its role in maintaining the regional anomaly.
The group applied a tracking algorithm (developed at the University of Reading) to three separate global reanalysis datasets to track and compile a comprehensive catalog of WDs impinging on the Karakoram-Himalayan region over the last four decades. Analysis of tracks through the Karakoram reveals the role of snowfall as a critical factor in mass balance estimates.
While previous studies have emphasized the role of temperature in the creation and maintenance of the anomaly over the years, this is the first time that the effect of precipitation on the nutrition of the anomaly has been highlighted. The researchers also quantified the impact of precipitation on the feeding anomaly. The scientists’ calculations show that the contribution of WDs in terms of snowfall volume over the Karakoram glacial core regions has increased by about 27% in recent decades, while precipitation derived from non-WD sources has significantly decreased by about 17%, further reinforcing their claims.”The anomaly provides a very bleak but nevertheless ray of hope for delaying the inevitable.” Recognizing the importance of WDs in controlling the anomaly, their future behavior may very well decide the fate of the Himalayan glaciers as well,” pointed out Dr. Kumar.
For more read: https://doi.org/10.1175/JCLI-D-21-0129.1
