Responding to the cascading and deadly impacts of glacial melting

Today, the fragile mountains in India’s Himalayan region are virtually crumbling under the impact of escalating ecological disasters. A rapidly warming planet, erratic rainfall, melting glaciers and widespread tree felling in this tectonically sensitive zone have together compounded the crisis as humanity tries to mould the Himalayas for developmental purposes. Indeed, the reckless manipulation of nature is taking its toll in a devastating manner, with deadly landslides and flooding placing precious lives and the entire ecosystem at risk. A 2019 Indian Institute of Science’s Divecha Centre for Climate Change study suggested that the 2,026 glaciers in the Himalayas’ Sutlej River basin alone were projected to lose up to 81 percent of their area, and many were likely to vanish by 2090, under a high greenhouse gas emission scenario. This will endanger millions of people among the mountain communities who are very likely to face future catastrophic flash floods from glacial lake water outbursts.

Since the October 2023 glacial lake outburst flood (GLOF) in the Indian state of Sikkim, that killed more than 100 people, India has seen rising incidents of naturally occurring Himalayan tragedies. Alarmingly, the Western Himalayas endured at least three major disasters this monsoon season. The repeatedly affected and battered region is where the rocks are fractured, fissured and disjointed tectonically. In the Eastern Himalayas, Sikkim, with its very steep, high mountain slopes has also faced severe disasters, including the recent destruction of a hydroelectric dam on the Teesta River, one of the main sources of water for Sikkim, caused by GLOF. Professor Mahendra P. Lama, the Sikkim government’s emeritus Chief Economic Adviser, had forewarned of GLOF impacts over two decades ago in his 2001 Sikkim Human Development Report.

According to Professor Lama, the phenomenon of jokulhlaup (glacier leap or glacial lake outburst flooding), has become a frequent and alarming occurrence in Sikkim. Given Sikkim is dotted with many glaciers, this is a potentially serious hazard. “It took 22 years for the people and the policy makers to see the devastation. I wish some of them had started working in its prevention,” Professor Lama lamented during a conversation with me recently. Indeed, as early as 1999, then provincial Chief Minister Pawan Chamling had conceded that Sikkim was facing serious problems visible to the naked eye, noting that the “Zemu glacier has depleted in size by more than 3-4 kilometres. The water in the Teesta River is flowing at an all-time low. We have had the warmest winter in living memory. These are all indications of things going wrong.”

India’s glacier crisis and remedies

Since the onset of the 18^th century industrial revolution, glaciers across the globe have retreated and thinned incrementally because of rising greenhouse gas emissions. The Himalayan Mountains, known as the Third Pole due to their extensive glacier and snow cover, is no exception and they have become highly vulnerable to climate change induced alteration in snowfall and rainfall patterns. As a result, glacier retreat and permafrost thaw (ground that remains frozen for at least two consecutive years) have decreased the stability of mountain slopes.

According to the Switzerland based World Glacier Monitoring Service, glacial loss has risen rapidly since the 1970s. India’s space research organization satellite imagery has also captured how fast melting glaciers are causing expansion of existing lakes and the formation of new ones, with the majority being moraine-dammed. A moraine is an accumulation of glacial debris made up of soil and rock and created by the erosion, transportation and deposition of material by the glacier. It often forms the walls of a lake, like earthen dams when the glacier recedes. In Sikkim’s South Lhonak Lake outburst disaster two years ago, 66.5 million cubic metres of sediment was displaced 40-45 kilometres downstream, reinforcing the need for modelling and observation.

Dr. Mohd. Farooq Azam, an eminent expert on glaciology, hydrology and climate change and a senior cryosphere specialist at Kathmandu based International Centre for Integrated Mountain Development, has also raised concern over the frequent occurrence of complex cascading disasters precipitated by heavy rainfall and the triggering of ice-rock avalanches due to slope failure. According to Dr. Azam, “Sikkim’s South Lhonak Lake outburst disaster is a stark reminder of the urgent need to monitor these fragile glacial and lake systems more closely.” While models do exist to simulate such events, the effectiveness of their performance depends heavily on the availability and quality of in-situ data. And while India is developing models for simulation and advance warning based on glacial lakes in the Alps, applying them to the Himalaya-Karakoram-Hindukush (HKH) region, given clear differences in geomorphology, leaves room for error.

Indeed, and although satellite data provides valuable information on glacier wastage, the connection between glacier dynamics and local meteorological or climatic conditions remains poorly understood across much of the HKH region – especially in the Eastern Himalayas where proglacial lakes are mostly concentrated. In order to improve modelling and early warning systems for GLOF, Dr. Azam recommends the collection of raw information from field-based settings, including meteorological observations, glacier mass balance measurements and detailed bathymetric surveys, which aim to map terrain details beneath a body of water, for accurate lake volume estimation.

Furthermore, there is a need for strengthening risk-transfer mechanisms for glacial hazards, which includes innovative insurance schemes for absorbing financial burden and climate-resilient infrastructure. But these are not sufficient to mitigate suffering. “Just as we conduct Environmental Impact Assessments (EIA) before infrastructure development, it is imperative to begin conducting Assessments of Environmental Impact (AEI) on existing and proposed infrastructure, especially in hazard-prone regions” noted Dr. Azam. Certainly, careful planning is required in high-risk areas, along with community preparedness through training and mock drills, to deal with this crisis more effectively. A timely alert in advance, even by a few minutes, can be lifesaving.

Mutual lessons as glaciers melt

As mentioned, global warming has accelerated the melting of glaciers, particularly in sensitive mountain ecosystems like that of the Himalayas. Here, the consequences of rising temperatures are manifested in multiple ways. First and foremost, it leads to the melting of mountain glaciers, which causes floods. Glacial coverage is also decreased, resulting in a reduction in the long-term availability of water for people, agriculture and hydro-electricity. Finally, as glacier cover diminishes gradually, the albedo – which is the amount of light reflected without being absorbed on a surface – also declines. This increases absorption of solar energy, thus intensifying the effects of warming.

Apart from the Himalayas, Canada is also facing significant glacier loss and Sikkim’s rapidly deteriorating glaciers offer stark lessons for Canada which has been witnessing glacial retreat in the Rocky Mountains where new moraine-dammed lakes are being created that could pose similar threats to life and property downstream. The Sikkim GLOF, in particular, should be carefully studied by Canadian experts because glaciers in the western part of Canada are melting twice as fast as they did a decade ago and the loss is equivalent to 22 billion pickup trucks worth of water annually. Moreover, Sikkim’s GLOF shows how sediment from the riverbanks aggravated the disaster’s intensity by adding to the glacier debris surging downstream.

India too can learn from Canada’s experience. Since 2023, Indian scientists have visited the Canadian High Arctic Research Station in Cambridge Bay, Nunavut twice to understand the impact of permafrost on human health, and overall climate change on glacial melting in the Himalayas. The UN has also designated 2025 as the International Year of Glacier Preservation and 2025–2034 as the Decade of Action for the Cryosphere, the term referring to glaciers, ice caps, snow and permafrost that are “melting at an unprecedented pace.” Dr. Azam feels it is a timely move that will help bring global focus to accelerating glacier loss and associated hazards. “Glacier-related disasters are rarely simple; they are often cascading in nature. The Sikkim disaster, for instance, was not just a typical GLOF. It was likely triggered by a permafrost thaw-induced landslide from the lateral moraine, which destabilized the South Lhonak glacial lake. This highlights the interconnected role of permafrost – a largely overlooked component in the Himalayas but extensively studied in Arctic regions like Canada,” Dr. Azam explained to me.

Canada’s long-standing experience in permafrost research, especially its impacts on infrastructure, ecosystems and slope stability, therefore offers valuable lessons for the Himalayan region. As glacial retreat in the Canadian Rockies creates new moraine-dammed lakes, both countries face similar risks and can benefit from knowledge exchange, particularly on permafrost dynamics, early warning systems, and hazard mitigation strategies. Furthermore, with India granted observer status in the Arctic Council in 2013, and cooperation in the fight against climate change with India mentioned in Canada’s 2022 Indo-Pacific strategy, it’s time that Canada-India Arctic cooperation becomes a point of focus for both countries.