Investigating changes in Himalayan glacier in warming environment: a case study of Kolahoi glacier

Abstract

There are strong evidences of melting in Himalayan glaciers at unprecedented rate in the past few decades. In the present study, the changes in Kolahoi glaciers in Himalaya are evaluated. Possible reasons behind these changes are also investigated. For this purpose, the changes in black carbon concentration, precipitation temperature and snow depth are investigated. A case study was carried out for the Kolahoi glacier situated at an altitude of 5245 m above sea level. The glacier area and snout change from 1857 to 2015 are investigated. It is reported in this study that the glacier has shrunk from 35 to 09.88 Sq Km. The rate of recession measured from 1922 to 2015 is reported to be 73.26 m per year. Furthermore, the rate of recession of snout is found to be 16.41 m per year from 1857 to 2015. The shirking of glacier area is linked to reduction in snow depth which in turn is affected by the increase in black carbon concentration, temperature and reduction in precipitation. Reanalysis data show that there is decrease of about 1.08 ± 0.65 cm per decade in snow depth over Kolahoi glacier during 1979 to 2013. There are decadal increasing trends of about 76 nanogram/m2 (statistically significant) and 0.39 °C (insignificant) in black carbon concentration and temperature, respectively, over Kolahoi. A decreasing trend of about 2.9 mm/month per decade in precipitation over the study area is also reported. Impact of increase in regional temperature on changes in snow depth is also quantified using inter-annual difference technique. It is reported that there is decrease of about 71 ± 24% in snow depth for each degree increase in temperature over Kolahoi. Reduction in snow depth as a result of increase in black carbon concentration, temperature and reduction in precipitation might have resulted in the shrinking of the Kolahoi glacier.