Glacier Melting in the Himalayas Poses Severe Risks to South Asia

Impact of Glacier Ice Loss in the Himalayas

GUWAHATI, Sept 5: According to Professor Nayan Sarma, a renowned river expert, the loss of glacier ice in the Hindu Kush Himalayas has doubled since 2000, putting two billion people in South Asia at significant risk.

In an interview, Professor Sarma, formerly of the Indian Institute of Technology Roorkee, discussed the recent catastrophic events in Nepal.

Assam Tribune: What are your thoughts on the recent devastation in Nepal?

Sarma explained that many Glacial Lake Outburst Floods (GLOFs) in the Himalayas are linked to the failure of moraine glacial dams. These lakes form as glaciers retreat, with meltwater accumulating between the proglacial moraine and the glacier itself. As the lake's volume increases, so does the pressure on the moraine dam.

When the glacier fragments or landslides occur, it can lead to the failure of the moraine dam, resulting in a GLOF.

Five months ago, significant scientific assessments, including key reports from the International Centre for Integrated Mountain Development (ICIMOD), issued warnings about the alarming rate of glacier ice loss in the region, which has doubled since 2000. This situation poses a severe threat to two billion people living downstream.

Unfortunately, these warnings appear to have been ignored.

When scientific organizations forecast a looming crisis months in advance, dismissing these findings as mere academic exercises rather than urgent policy actions is a serious oversight. Despite evidence showing that smaller glaciers are rapidly diminishing, authorities have not implemented necessary safety protocols, evacuation plans, or protective infrastructure for vulnerable communities.

Satellite imagery suggests that a significant landslide may have impacted the glacier, leading to a massive ice detachment near Langtang Lirung, which fell into the valley below, registering as a 5.2 magnitude seismic event. The debris temporarily blocked the Lhende Khola river, creating an unstable natural dam. When this barrier failed under increasing water pressure, it unleashed a catastrophic flash flood of water, mud, and rock through the Trishuli river basin.

AT: Is there a similar threat in North East India?

Sarma indicated that GLOFs are a constant danger to communities downstream and should be considered in any planning for the lower regions of North East India. The frequency and risk of GLOFs are expected to increase due to climate change. As temperatures rise, new lakes are forming, and existing ones are expanding, which raises the potential for flooding in mountainous areas.

GLOFs present an escalating threat to North East India due to retreating glaciers and growing infrastructure in Himalayan ecosystems. Factors such as landslides, intense monsoon rains, avalanches, or minor seismic activities can destabilize fragile moraine dams, leading to sudden and catastrophic water releases.

AT: Are there any studies on the number of glacier lakes in Tibet?

Sarma noted that the Hindu Kush Himalaya region is home to over 63,700 glaciers, covering approximately 55,782 square kilometers. Recent hazard assessments classify hundreds of these lakes as high or very high risk, posing threats to downstream communities and infrastructure due to potential GLOFs.

AT: Given that the Brahmaputra and its northern tributaries are fed by glaciers, could glacier melting cause disasters in North East India?

Sarma warned that accelerated melting of Himalayan glaciers could significantly exacerbate natural disasters in North East India, especially when combined with heavy monsoon rains. ICIMOD has cautioned that rising temperatures are destabilizing the Himalayan cryosphere, leading to ice loss that is over 65% faster than in previous decades.