Glacier retreat, expanding glacial lakes, thawing permafrost and unstable slopes are increasing the risk of disasters in the Himalayas.
Hazards such as the risk of GLOFs, landslides and cascading disasters rapidly affect communities far downstream.
Sparse monitoring and weak real-time data sharing can reduce warning time. India and neighbours have expanded monitoring, but on a regional scale, more high-altitude data sharing is needed.
...
In a warming world, rising temperatures in high mountain regions are driving glacier retreat and melting, contributing to an increase in the number and area of glacial lakes. As glaciers retreat, they can create new lakes or expand old ones, sometimes contained by natural dams made of ice or moraines — ridges of rock, sediment and debris left behind by glaciers.
If these dams fail, glacial lake outburst floods (GLOFs) can release huge volumes of water and debris, severely flooding downstream communities and infrastructure. In some cases, GLOFs involve rockfalls or the collapse of entire mountain slopes with cascading impacts. Or there can be avalanches — massive, rapid downhill flows of rocks, ice and snow.
Scientists have improved glacier and lake monitoring in the Himalayan region, but large gaps remain in data collection, sharing and processing. This affects real-time early warning for river systems that run across international borders. In the aftermath of the recent Nepal flood disaster, this explainer looks at the relevance of these issues.
...
Himalayan flood risk is changing not only because the climate and cryosphere — frozen water part of the Earth system — are changing, but because the source of a disaster and the people affected by it can increasingly be separated by hundreds of kilometres and one or more international borders, pointed out Vijaykumar P., Assistant Professor in the Department of Environmental Sciences, University of Kerala.
Downstream communities — not only in the mountains, but also the plains — demand science-based inputs for disaster risk reduction. Still, hydrological data-sharing mechanisms between China and India are inadequate at present, despite earlier agreements, as government reports suggest.
...
On a broader scale, despite improvements in glacier monitoring, only a small fraction of glaciers are closely studied, and data coverage remains uneven across the region.
Early warning systems for early action to save lives and protect livelihoods, property, assets and infrastructure must become a priority agenda, experts pointed out.
