Title: Impact of climate change on cryosphere and streamflow in the north-western Himalayan region

Abstract

The climate of the Himalayas is vulnerable and interlinked with global-scale climate changes, and the hydrology of the region mainly depends on the cryosphere. This is the first study that has created glacier and glacier lake inventory that links the impact of cryosphere on streamflow to land system dynamic changes under the changing climate of the Upper Jhelum River Basin (UJRB) of the Kashmir Himalayan region. This study uses a series of satellite data (1980–2016) to assess the depletion of Snow Cover Area (SCA), deglaciation, and dynamics of glacial lakes. The results suggested an overall rise in temperature (TMax=0.05ºC a-1; TMin=0.02ºC a-1; Tavg=0.06ºC a-1) and a decrease in precipitation (2.9 mm a-1) between 1980 and 2016 with a significant increase in annual average temperature and decrease in annual precipitation at stations located at higher altitudes. The Snow Cover Area (SCA) showed a significantly decreasing (p<0.01) trend in the glacierized sub-basins. The findings of this study reveal the high occurrence of glacier disintegration and deglaciation. During the period 2010-2016, a rapid rate of deglaciation was observed (18.34±0.14 km2), followed by 1992-2000 (15.61±0.13 km2). The average rate of retreat was observed to be 6.81± 1.5m a−1 with a total retreat of 267±80m during 1980-2016, which is higher than reported from surrounding mountain ranges in the Himalayas. The mapped 244 glacial and high-altitude lake inventory covers a total surface area of around 15 km2, with 5.87 km2 (40%) covered by 25 bedrock dammed lakes. The annual average discharge in UJRB significantly increased from 1991 to 1998 and was observed to be higher than the annual average of the respected gauge stations but shows significant depletion from 1998 onwards. The streamflow depletion under climate change is one of the reasons for land system dynamics in UJRB.