This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Does the devastating flooding unleashed by the collapse of a section of a glacier in the Nepali Himalayas signal a new kind of risk in a world warmed by climate change? Here's what scientists told AFP.
On Friday, Nepal issued an alert about the risks posed by a large body of water formed in China's Tibet region following the collapse of a section of a glacier two days earlier. That collapse killed at least 584 people, and more than 2,400 remain missing. "Once you take a piece of mountain away, then there's probably another piece right beside it that's been destabilized by the removal.
And so you could have a similar thing collapse," Simon Cox, principal scientist at New Zealand's GNS Science research institute, told AFP. "You may well have more material to fall down right from up at the source area, and the same thing could happen immediately again." According to the United States Geological Survey (USGS), the resulting flood was triggered by a glacier collapse so violent that it generated energy equivalent to a magnitude 5.2 earthquake and caused numerous landslides. Etienne Berthier, a glaciologist at the French National Centre for Scientific Research (CNRS), told AFP, "we can't rule out" the risk of similar phenomena occurring elsewhere.
"They reach such proportions in the Himalayas because the terrain and the region's high tectonic activity amplify the likelihood of such events occurring on that scale," he explained. Other regions may have similarly "dynamic" glaciers—such as Alaska—but "this happens in completely uninhabited areas." "We have seen a dramatic increase in the number of extremely hazardous flows such as this globally in the past decade or so," Tristram Hales, a professor of environmental hazards at Cardiff University, told AFP, citing events in the Himalayas and Switzerland. Scientists warn that rockfalls and landslides triggered by earthquakes or the thawing of permafrost—which is being accelerated by climate change—are more likely than entire sections of a mountain coming down.
These risks are greater for people when towns, roads or tourist sites are located nearby. In the Alps, this year's extremely hot summer saw a record number of rockfalls, including some that were fatal—the vast majority of which can be attributed to the climate crisis, Ludovic Ravanel, a geomorphologist at the CNRS, told recently. In Switzerland, the municipality of Randa, home to some 400 people, fears a glacier collapse in the coming days and has established safety perimeters following several rockfalls, according to the national press.
The disaster in Nepal was probably very hard to predict, Berthier said, adding that rock movements will need to be analyzed to see whether signs of instability were visible in the preceding weeks or months. But risks are far more apparent when glacier-fed lakes form. These can drain suddenly and catastrophically, a phenomenon known as glacial lake outburst floods (GLOFs).
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