Melting mountain glaciers pose a rising flood danger to some 15 million individuals around the globe, researchers stated in a report printed on Tuesday, with communities in Asia dealing with the largest hazard.
| Photo Credit: AP
Melting mountain glaciers pose a rising flood danger to some 15 million individuals around the globe, researchers stated in a report printed on Tuesday, with communities in Asia dealing with the largest hazard.
Runoff from melting glaciers usually swimming pools in shallow lakes, held again by rocks and particles. The danger comes when a lake overfills, bursting by way of its pure barrier and sending a torrent of water dashing down mountain valleys.
Scientists have assessed for the primary time how many individuals globally are in danger from these floods, discovering that greater than half of weak populations dwell in India, Pakistan, China, and Peru.
Danger is highest, they report in a research printed in the journal Nature Communications, when numerous individuals dwell close to a lake.
“Our work does not just focus on the size or number of glacier lakes – no disaster is natural – it is the presence of people, especially vulnerable people, in the landscape that causes a disaster,” stated Stuart Dunning, a bodily geographer at Britain’s Newcastle University, and a co-author of the research.
Glacial lake outburst floods are projected to worsen in a warming local weather.
Collectively, the world’s glaciers misplaced about 332 gigatonnes of ice a 12 months between 2006 and 2016. Since 1990, the quantity and quantity of glacial lakes worldwide have every elevated by about 50%.
In the excessive mountains of Asia, some 9 million individuals dwell close to greater than 2,000 glacial lakes. In 2021, greater than 100 individuals had been killed in India in an outburst flood in its northern mountains.
Heating up the Himalayas
Compared with mountain glaciers in the Alps and North America, Asia’s icy locations should not as nicely monitored – most lack long-term observations of how they’ve modified over time.
The best-studied glacier in the Himalayas is north India’s Chhota Shigri, which has 20 years of mass steadiness measurements – the distinction between how a lot ice a glacier positive factors and loses in a 12 months.
In 2022, India suffered blistering temperatures and close to the top of the 12 months, scientists headed into the Himalayas to measure Chhota Shigri’s mass.
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Their findings, shared with Reuters, revealed the best-studied glacier in the Himalayas had skilled its worst 12 months on report; Chhota Shigri misplaced 3 times as a lot mass in 2022 in contrast with its 2002 to 2022 yearly common.
“The impacts are already visible as the glacier is thinning and retreating,” stated Farooq Azam, a glaciologist on the Indian Institute of Technology Indore who displays Chhota Shigri. This will likely be “impactful to downstream water availability in near future”, he stated.
Satellite observations additionally present that the glaciers in the Himalayas are in a state of total decline.
“The ice is really melting significantly during the last decades – mass loss is accelerating,” stated Tobias Bolch, a glaciologist with Graz University of Technology in Austria.
From 1990 to 2015, glacier protection in the Himalayas shrank by about 11%, in keeping with July 2022 research.
During the identical time interval, Himalayan glacial lakes elevated by about 9% in quantity, and 14% in space. More than 200 lakes now pose a really excessive hazard to Himalayan communities, in keeping with 2022 analysis.
