Climate change impact on cryosphere and streamflow in the Upper Jhelum River Basin (UJRB) of north-western Himalayas

The critical significance of keeping the current information about the extent and dynamics of the cryosphere in the Himalayas cannot be understated. 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. Moreover, observational long-term hydrometeorological data were used to understand the variability in temperature, precipitation, and track changes of land system dynamics under depletion of streamflow. The results suggested an overall rise in temperature (TMax = 0.05 ºC a−1; TMin = 0.02 ºC a−1; Tavg = 0.06 ºC 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 SCA showed a significantly decreasing (p < 0.01) trend in the glacierized sub-basins with an annual rate of decrease of -0.78% a−1, -0.15% a−1, -0.03% a−1 -0.90% a−1 for Lidder, Sindh, Vishow, and Rambiara sub-basins, respectively. 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 ± 1.5 m a−1 with a total retreat of 267 ± 80 m 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 glacial expansion and creation of new lakes are observed to be because of increasing glacier and snow melting between 1980 and 2016, which increases the risk of GLOF events in the future. 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. The area under agriculture has decreased up to 63% with a massive expansion of built-up (399%), aquatic vegetation (523%), and plantation (765%) between 1992 and 2015.