An Exigency for Ice Core Studies to Determine Spatio-temporal Variability in Moisture Sources and Impact of Black Carbon – Mineral Aerosols on the Himalayan Glaciers

Abstract

Himalayan glaciers‒ the store house of fresh water outside the polar region contributes ~45% of the total river flow by glacial melt in the Indus, Ganga and Brahmaputra watersheds which supports the livelihood of ~500 million people . The sustainability of these rivers is being questioned because of the growing evidences of accelerated glacier retreat in the recent decades, which is expected to have cascading effects on the mountainous areas and their surrounding lowlands. The rapid melting of Himalayan glaciers reveals their sensitivity to ongoing changes in climate dynamics, and if the current trend continues, rivers that rely heavily on snow/ice melt are expected to suffer hydrological disruptions to the point where some of the most populous areas may ‘run out of water’ during the dry season. Therefore, efforts are being made to study the glacier mass balance trends in order to understand the patterns and causes of recent recessional trend. Despite their importance, the absence of long-term mass-balance and remote sensing data restricts our knowledge of the Himalayan glaciers’ sensitivity/ response to climate change. Furthermore, such studies may be insufficient unless are compared to long-term glacier fluctuations (millennial and multi-millennial time scales), which aid in better understanding the natural trends of and human impacts on climate change, as well as assessing the causes and possible future of contemporary shrinking glaciers. This will also improve our understanding of past glacier behaviour in the context of primary causes of glacier change, which is critical for water resource management and understanding climate variability in high alpine areas where alternative proxy climate archives are typically scarce. Therefore, it is pertinent to pool our scientific resources and energy (i) towards understanding the Himalayan glaciers’ feeders (precipitation sources) and how they changed over time (geological and historical), as well as the causes of glaciers recession, one of which has been identified as (ii) black soot (carbon) in aerosol pollution.