Glacial lakes could cause flooding if an ice or rock dam holding again the water fails, placing an estimated 15 million individuals in danger, an evaluation has discovered
Environment
7 February 2023
Flooding of glacial lakes, like Nepal’s Imja glacial lake pictured right here, might put hundreds of thousands in danger Prakash Mathema/AFP through Getty Images
As many as 15 million individuals dwell in areas that might be flooded by a pure dam failing at a glacial lake, in accordance with the primary world evaluation of the hazard.
Tom Robinson on the University of Canterbury in New Zealand and his colleagues recognized glacial lakes in satellite tv for pc imagery. They then decided the variety of individuals residing inside 50 kilometres of every lake, and inside 1 kilometre of the river the place water would movement within the occasion of a glacial lake outburst flood (GLOF). These floods can occur when an ice or rock dam holding again a glacial lake fails, or a rock slide sends water sloshing over a pure dam.
The researchers discovered as much as 15 million individuals might be affected, with 9 million within the Himalayas, 2.5 million within the Andes and a pair of.2 million within the Alps. More than half of the 15 million dwell in both India, Pakistan, Peru or China.
Outburst floods are unlikely at many glacial lakes, and the research presents a simplified view of the areas any flooding would have an effect on, says Simon Allen on the University of Zurich in Switzerland, however he says the worldwide view helps draw consideration to susceptible and understudied areas.
Pakistan, as an illustration, has 2.1 million individuals residing in probably at-risk areas, however lakes there are much less effectively understood than lakes in close by Nepal, the place the federal government has constructed costly spillways on the most harmful lakes and put in early warning techniques. In some circumstances, a flood wave from an outburst might arrive in beneath an hour, with no prior warning.
Lakes in Peru and elsewhere within the Andes mountains, the place hundreds of individuals have been killed by glacial lake floods for the reason that Fifties, additionally haven’t acquired ample consideration, says Robinson.
Glacial lakes are rising quickly in quantity and dimension as local weather change melts extra ice, however the frequency of glacial floods has decreased for the reason that Nineteen Seventies, says Stephan Harrison on the University of Exeter within the UK. As with warming after the Nineteenth-century Little Ice Age, there could also be a long time of lag between warming and lakes rising giant sufficient for an outburst, he says.
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Source: www.newscientist.com