The catastrophic flooding triggered by a glacier collapse in the Nepalese Himalayas has raised fresh concerns about the changing risks in a warming world.
Scientists that similar disasters could occur elsewhere, although it remains too early to establish whether climate change directly contributed to this particular event.
Risk Of Another Collapse
Nepal issued an alert on Friday over a large body of water that formed in Tibet after part of a glacier collapsed two days earlier. The disaster reportedly killed at least 584 people, while more than 2,400 were still missing.
Simon Cox, principal scientist at New Zealand’s GNS Science, warned that the collapse of one section of a mountain can destabilise surrounding material. This means another section could potentially give way, triggering further landslides or flooding.
The US Geological Survey said the collapse was so powerful that it released energy comparable to a magnitude 5.2 earthquake and set off numerous landslides.
Why The Himalayas Are Vulnerable
Scientists say the Himalayas face particular risks because of their steep terrain and high level of tectonic activity.
Etienne Berthier, a glaciologist at France’s National Centre for Scientific Research, said similarly dynamic glaciers exist in other regions, including Alaska. However, many such areas are remote and uninhabited, meaning the human impact can be far smaller.
Tristram Hales, a professor of environmental hazards at Cardiff University, said extremely dangerous flows have been observed more frequently around the world over the past decade, including in the Himalayas and Switzerland.
Climate change is also altering conditions in high mountain regions. Rising temperatures are accelerating the thawing of permafrost and changing glacier and snow conditions, potentially increasing the instability of mountain slopes.
Rockfalls and landslides remain more common than the collapse of an entire section of a mountain. However, they can become deadly when settlements, roads or tourist areas are located below unstable slopes.
Can Such Disasters Be Predicted?
Scientists say predicting a sudden glacier or mountain collapse remains extremely difficult.
Berthier said the Nepal disaster may have been particularly challenging to forecast. Researchers will need to examine changes in the surrounding rock and terrain to determine whether there were signs of instability before the collapse.
Some glacier-related hazards, however, can be monitored more effectively. When meltwater accumulates and forms a lake behind or beside a glacier, it can sometimes be released suddenly, producing a glacial lake outburst flood, or GLOF.
In the Alps, experts regularly monitor glacial lakes and assess the risk of overflow or sudden drainage. Such systems can provide warnings when dangerous changes are detected.
What Is The Climate Change Connection?
Despite growing concern over climate-related mountain hazards, scientists caution against immediately blaming the Nepal disaster on global warming.
The International Centre for Integrated Mountain Development said climate change is affecting glaciers, snow, permafrost and mountain slopes across the Hindu Kush Himalaya. However, it said there was not yet enough evidence to determine what role climate change played in this specific event.
Scientists would need to conduct an attribution study comparing the likelihood of such an event under today’s warmer climate with conditions before widespread fossil-fuel-driven warming.
The disaster highlights the growing dangers faced by communities living in fragile mountain environments. But determining whether climate change made this particular collapse more likely will require further scientific investigation.
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