Reconstructing climate variability during the last four millennia from trans-Himalaya (Ladakh-Karakoram, India) using multiple proxies

Abstract

In this communication we reconstruct climate variability of Ladakh, Trans-Himalaya region, on sub-century timescale spanning the last four millennia (~4130 to 260 cal yr ‘before present’ (BP)). To achieve this objective, we measured a suite of physical, biotic and inorganic proxies of a lacustrine sequence. In general, between ~4130 to ~2640 cal yr BP proxy records reveal climate variability following a typical pattern of the northern hemispheric climate and appear to be dominated by westerlies. Thereafter, the Indian Summer Monsoon (ISM) forcing appears to dominate regional climate. The former period appears to have experienced human presence as evidenced by an invasive species of diatom –Didymosphenia and charcoal, likely originating from human activities on trading routes with Central Asia, China and Tibet. After ~2640 cal yr BP, when ISM started governing the climate of the Ladakh- Karakoram region, it probably induced high-frequency climate variability leading to disasters related to landslides, debris flows, avalanches etc., eventually reducing the intra-boundary trade. A similar situation appears to be gripping the region again as meteorologically recorded precipitation data from Ladakh reveals arrival of high-frequency monsoonal variability in the region with recurrent flash floods (e.g., 2010, 2013).