Hydrometeorological progression of the Himalayan cryosphere: The Karakoram predicament

The anomalous behaviour of the Karakoram glaciers has been a decade-long discussion. While a lot of effort has been given to understanding this phenomenon, little has been explored with respect to the factors that govern glacier accumulation rates. We performed a time-series analysis of 17 Himalayan glaciers to evaluate the Accumulation Index (AI), examine the ice accumulation/ablation balance of each glacier, and investigate the natural periodicities in regional climatic behaviour. Based on the AI, the Himalayan glaciers have been char-acterised as 'glacier-positive' and 'glacier-negative'. Glacier-positive behaviour in the Karakoram is favoured by global meteorological and local topographical factors. Analysis of 120 years of meteorological data shows a significant positive trend in winter and annual precipitation in the northwestern Himalayas, linked to surfacial warming and the Indian Ocean Dipole, while local factors such as slope, aspect and supraglacial debris constrain summer ablation. Additionally, the Karakoram precipitation is periodic in nature, demonstrating anti-correlation with decadal-scale precipitation records from the remaining Himalayan glaciers. Both local and global factors explain the anomaly in the Karakoram or the lack of it in other Himalayan glaciers.In a potentially warming planet, glacial accumulation rates are becoming increasingly sensitive to ambient temperatures, where glacier mass budget turns sharply negative at temperatures above 263 K due to accelerated summer ablation which overcompensates wintertime accumulation. This makes the Karakoram more sensitive to global meteorology than local factors. Therefore, it is important to address whether the Karakoram anomaly is an isolated climatic event or will it succumb to global climate change like the remainder of the Himalayan glaciers.

Automated summary

Research indicates that the anomalous behavior of Karakoram glaciers is influenced by global meteorological and local topographical factors. Precipitation in Karakoram demonstrates periodicity and shows anti-correlation with precipitation records from other Himalayan glaciers. Glacial accumulation rates are becoming increasingly sensitive to ambient temperatures in a potentially warming planet.