Intimidating Evidences of Climate Change from the Higher Himalaya: A Case Study from Lahaul, Himachal Pradesh, India

Climate change manifestations are no longer shades of grey, but the unprecedented evidences and repercussions are now in black and white. The mounting evidences from the high-mountain areas via accelerated glacier melting, permafrost thaw and expansion of glacier lakes are becoming a major concern for high-mountain communities, environmentalists and policy makers. The accelerated expansion of glacial lakes in the higher Himalaya is not just the expression of glacial melting to climate warming, but poses a serious threat in terms of glacial lake outburst floods (GLOFs). The present investigation focuses on a moraine-dammed pro-glacial lake (MDPGL) in the Kadu Nala valley (Lahaul, western Himalaya, India) that has evolved in less than a decade and has been expanding at an alarming rate since 2014. The data show that the actual development of the lake started in 2010 and has expanded to ~ 0.18 km 2 in 2021. The limitation in direct correlations of warming impacting the cryosphere in the higher Himalayan region and hence in the present study is the scarcity of metrological data (especially temperature and precipitation). Therefore, the climate research data (CRU), along with the inferences from tree ring width data, have been used to understand the climatic impacts in this area. Considering that forecasting is a very important aspect of environmental studies, we have used four different forecasting methods to estimate the glacier and glacial lake change scenarios in the present study. The ongoing trends and the model projections of future show accelerated glacier loss and associated glacial lake expansion in Kadu Nala valley and highlight the need for a close monitoring of such lakes, because it has been demonstrated that even the GLOFs from small pro-glacial lakes have the ability to transform into a giant trans-border flood and debris flow. An analogous trend, magnitude and accelerated glacier melting and expansion of glacial lakes in the Himalaya may be attributed to a regionally coherent climate forcing, consistent with atmospheric as well as elevation-dependent warming.