Climate change, with its pervasive impact across the globe, is significantly affecting Earth's natural systems, including glaciers, particularly those in mountainous regions inhabited by large populations. Rising temperatures are causing glaciers to melt gradually, leading to the formation of unstable glacial lakes. When these fragile holding systems collapse, they trigger catastrophic events known as Glacial Lake Outburst Floods (GLOFs). These floods strike suddenly, often without warning, causing widespread destruction. The aftermath includes violent loss of life, severe injuries, and long-term trauma for survivors.
The phenomenon of GLOFs arises from the glacial lake retreat, a process driven by rising temperatures caused by climate change. During summer, glaciers melt at a faster rate than ice forms in winter, resulting in their gradual retreat. As glaciers recede, they leave behind a natural barrier of rocks and debris, known as a moraine, which blocks the glacial valley and forms a moraine-dammed glacial lake. The accumulation of excess melt-water in this lake during warmer months creates an inherently unstable system. If the moraine fails, it can trigger a catastrophic release of water, causing a GLOF.
In developing countries, where many mountain dwellers rely on daily physical labour for their livelihoods, such disasters can have devastating and life-altering consequences. The loss of earning capacity and the emotional toll can leave communities struggling to rebuild for generations.
Governments in countries vulnerable to the risks of Glacial Lake Outburst Floods are increasingly recognizing the severity of this threat and taking proactive disaster management measures to address it. These measures include the continuous monitoring and glacial lake risk assessment of the lake conditions to mitigate potential disasters. One of the most immediate and critical steps is reducing the water volume in glacial lakes. This GLOF mitigation strategy helps ensure that, during peak water flow seasons caused by melting glaciers or heavy rainfall, the excess water can be safely accommodated within the lake basins, minimizing the risk of overflow or catastrophic breaches.
To support these efforts, advanced monitoring systems are deployed, including the installation of sensors in and around the glacial lakes. These sensors provide real-time data on water levels, temperature fluctuations, and other critical parameters, enabling authorities to detect early warning signs of potential flooding. By using these GLOF early warning systems, governments can implement pre-emptive measures, such as controlled water release or evacuation planning, to protect downstream communities and infrastructure. This combination of technological innovation and strategic planning is a vital step in reducing the devastating impacts of GLOFs on both human lives and the environment.
The figure (a) from Nature.com effectively highlights GLOF (Glacial Lake Outburst Flood) risk points, with clear colour coding to distinguish various mountain ranges. "HMA" represents the High Mountains of Asia, "PNW" corresponds to the Pacific Northwest ranges, and "HAOC" refers to the High Arctic and Outlying Countries. The accompanying pie charts illustrate the proportion of exposed populations within these mountain regions.
�Figure (b) provides a comparative perspective by showing the percentage of exposed individuals relative to each country's total population. The grey bars on the right indicate the number of exposed persons, while the coloured bars on the left represent the total population of each country.
