An estimated 15 million people could be at risk from glacial lakes, which could cause flooding if the ice and rock dams that hold them back are broken, an analysis finds.
environment
February 7, 2023
Glacial lake flooding, like Nepal’s Imja Glacial Lake pictured here, could endanger millions of people Prakash Matema/AFP via Getty Images
As many as 15 million people live in areas where natural dam failures in glacial lakes could cause flooding, according to the world’s first analysis of disasters.
Tom Robinson and his colleagues at the University of Canterbury in New Zealand have identified a glacial lake in satellite imagery. We then determined how many people live within 50 kilometers of each lake and within 1 kilometer of a river that would drain in the event of a glacial lake outburst flood (GLOF). These floods can occur when ice and rock dams that dam glacial lakes break, or rock slides splash water onto natural dams.
Researchers found that 9 million people in the Himalayas, 2.5 million in the Andes, 2.2 million in the Alps, and up to 15 million could be affected. More than half of the 15 million people live in India, Pakistan, Peru or China.
Flooding is unlikely in many glacial lakes, and the study provides a simplistic view of the areas affected by flooding, says Simon Allen of the University of Zurich, Switzerland. But a global perspective can help focus attention on vulnerable and understudied regions, he says.
In Pakistan, for example, where 2.1 million people live in potentially endangered areas, the lakes there have been degraded by the government building expensive spillways and early warning systems in the most dangerous lakes. It is not as well understood as the nearby Nepalese lake where it was set up. In some cases, without prior warning, flood waves from explosions could reach within an hour of him.
Lakes in Peru and elsewhere in the Andes, where thousands of people have died in glacial lake floods since the 1950s, have also not received enough attention, says Robinson.
The number and size of glacial lakes is expanding rapidly as climate change melts more ice, but the frequency of glacial flooding has decreased since the 1970s, says Stephen Harrison of the University of Exeter, UK. said. Similar to warming since the Little Ice Age in the 19th century, it could take decades for the lake to explode from warming, he says.
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