An Assessment of Changes in the Retreat Pattern of Khangpu and Kangkyong Glaciers, Sikkim, India (1980-2020)

A glacier is a stubborn mass of dense ice constantly moving under its weight. Glaciers form where snow has accumulated over centuries, often centuries and beyond erosion. One of the most dramatic pieces of evidence that the global climate is warming is the retreat and disappearance of mountain glaciers around the world. The present study is all about the changing patterns of Changmekhanpu and Kangkyong Glacier in the Tista Basin in Sikkim. The study is based on observations in 4 decades from 1980-1990, 1990-2010, 2000-2010, and 2010-2020. The work is done with the help of remote sensing techniques and geographic information system software. The demarcation of glaciers is extracted from NASA, USGS, GLIMS, and Google Earth Pro Data with the help of SRTM DEM, Landsat 5 ETM, and Landsat 8 OLI. The processed satellite images are obtained using ArcGIS 10.5. All these satellite images are used to delineate glacier boundaries, estimate glacier length, and calculate snout retreat and snow cover. The present length of the Changmekhangpu Glacier is 6.4 km. The length increased by 197 meters in 40 years, from 1980 to 2020. The current length of Kangkyong Glacier is 8 km. The length was decreased by 660 meters in 4 decades. The area of both glaciers decreased by 1.19 km and 2 km, respectively. The snout recession had fluctuations. At last, the snow cover index/NDSI indicates the change in climate affects the glacier's topography. The results and analysis have been explained in this work.