Dehradun, August 28: The recent natural disaster in Nepal has once again brought to light the dangers posed by glaciers, sudden floods, and climate change in the Himalayan region. Scientist Dr. Manish Mehta explained the potential causes of the incident, stating that research, agency reports, and satellite images suggest a significant avalanche descended from a high-altitude area. This caused a temporary blockage of water and debris downstream. Subsequently, loose and disorganized debris accumulated in front of the glacier was swept away by the swift current.
Dr. Mehta noted that the steep slopes caused the debris to mix with water, forming a slurry that rapidly moved downward. This assessment is based on studies of satellite images from various institutions, including ISRO, USGS, and ICIMOD. Global warming is causing glaciers to retreat, leading to the accumulation of loose debris, moraines, and recessional moraines in front of them. Due to the slope and geographical structure, water can accumulate in these areas, forming pro-glacial, peri-glacial, or supra-glacial lakes. When the pressure in such lakes increases and their dam breaks, it results in a Glacial Lake Outburst Flood (GLOF).
Dr. Mehta emphasized the significant role of climate change in these processes. Since 1850, the continuous retreat of glaciers has resulted in the accumulation of large amounts of loose debris. Additionally, rising temperatures are reducing snow-covered areas while increasing rainfall in high-altitude regions. Rain can rapidly wash away this loose material, significantly enhancing erosion potential.
When questioned about the role of human activities in China or Tibet concerning the Nepal incident, he stated that there is currently insufficient research available to draw any definitive conclusions. The Himalayas are a young and geologically active mountain system, where such natural processes have occurred in the past and will continue in the future. The material that came from above was related to the glacier area, which is extremely sensitive and fragile.
Highlighting lessons for India from the Nepal incident, Dr. Mehta referenced past events in Kedarnath, Dharali, and Rishiganga. He advised that people living in Himalayan areas should avoid settling right next to rivers. There is a need to develop settlements at a safe height above riverbeds and incorporate this into disaster and land-use policies. Any lake, whether natural, artificial, or glacial, can cause severe downstream damage if it breaks. However, stable lakes can remain safe for extended periods.
According to Dr. Mehta, examples of GLOF-related incidents exist in Bhutan, Pakistan, China, and India. Risks persist across various regions from northeast to northwest Himalayas. Due to the complex and rugged topography of the Himalayas, it is not easy to install early warning systems in every valley. Efforts are ongoing to develop monitoring and warning systems in some sensitive locations. Accurate predictions of lake breakage are challenging. However, regular monitoring of increasing glacial lakes can help understand risks and provide timely warnings.
Dr. Mehta stated that glaciers are crucial water sources for approximately 1.3 billion people in Asia. Glaciers themselves are not inherently dangerous; rather, the rapidly changing conditions they create are concerning. He urged the public to engage in environmental protection by reducing vehicle emissions, dust, fires, and aerosols, planting more trees, and decreasing carbon emissions.
He concluded that to reduce the risk of Himalayan disasters, it is essential to work together on scientific monitoring, improved land-use policies, public awareness, and environmental conservation.
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