Glacier surges are often linked to instabilities in temperature and/or precipitation combined with the deformable properties of a glacier. Excessive rise in precipitation or temperature may cause glaciers to surge. New research by experts at ICIMOD and Yunnan University shows that glacier surges are still occurring in western Kunlun Shan, China. The surge of Guliya ice cap that occurred between 2005 and 2015 hints that surge-like instability and collapses in the region may increase in the future. This illustrates the need for regular glacier monitoring.

The study – published in Remote Sensing of Environment – observes the changes of Guliya ice cap during the same observation period (2005–2015) using remote sensing and validated remote-sensing results for the first time using differential global positioning system field data at 6,000 masl. Most of the changes in the surface elevation of Guliya ice cap remain within 10 metres both negative and positive between 2005 and 2015. Earlier studies in the region had shown a slight retreat during the 1970s to the 2000s, but this research has revealed that glacier mass balance has been stable.

Interestingly, this study observed in the summer of 2015 the surge of a north-facing glacier which has no previous record of surging. The surge was triggered by ice movement from the accumulation zone (upper part of the glacier) to the ablation zone (lower part of the glacier). The process reduced glacier surface elevation on the upper part of the glacier and increased the surface elevation of the lower part of the glacier, thereby creating the surge. A similar surge and consequent collapse were recorded a year later in 2016 in nearby glaciers of western Tibet.

This finding is particularly important as it shows that instability of glaciers in the western Kunlun Shan and that surge-like activity has existed at least since 2015, as also supported by the collapse of Aru Glacier in 2016. “This calls for the need for regular monitoring of the glaciers in the region,” said Sher Muhammad, Remote Sensing Specialist at ICIMOD, who is a co-author of the study.

Monitoring glacier changes is important for understanding and assessing the impact of climate change, disaster mitigation from associated hazards, and water resources management. Glaciers are widely retreating across High Mountain Asia, but the Karakoram and western Kunlun Shan are possible exceptions to this general trend. Glaciers in these regions, however, are characterized by surges and consequent collapses, often exacerbated by climate change, and they are now becoming a common phenomenon in these regions. Given the regions’ harsh geographical features and inaccessibility, ground validation data are scare.

Sher Muhammad

Chimi Seldon

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