Eastern Eye (UK)

People in Asian mountains face high glacier floods risk



VIOLENT flooding from glacier lakes formed or enlarged by climate change threatens at least 15 million people worldwide, most of them in four countries, researcher­s said last Tuesday (7).

More than nine million people across so-called High Mountain Asia live in the path of potential glacial lake outburst floods, including five million in northern India and Pakistan, they reported in Nature Communicat­ions.

China and Peru are also especially exposed to the danger of abrupt flooding from melting glaciers, according to the study.

The danger is highest when a large number of people live near a lake, researcher­s said.

“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,” said Stuart Dunning, a physical geographer at Newcastle University, and a co-author of the study.

Glacial lake outburst floods are projected to worsen in a warming climate, according to scientists.

Collective­ly, the world’s glaciers lost about 332 gigatonnes of ice a year between 2006 and 2016. Since 1990, the number and volume of glacial lakes worldwide have each increased by about 50 per cent.

Glacier lakes are particular­ly unstable because they are most often dammed by ice or sediment that is composed of loose rock and debris. When large volumes of accumulati­ng water bursts through these accidental barriers, massive flooding can occur downstream.

In the high mountains of Asia, some nine million people live near more than 2,000 glacial lakes. In 2021, more than 100 people were killed in India in an outburst flood in its northern mountains.

Compared with mountain glaciers in the Alps and North America, Asia’s icy places are not as well monitored. Most lack long-term observatio­ns of how they have changed over time.

The best-studied glacier in the Himalayas is north India’s Chhota Shigri, which has 20 years of mass balance measuremen­ts – the difference between how much ice a glacier gains and loses in a year.

In 2022, India suffered blistering temperatur­es and near the end of the year, scientists headed into the Himalayas to measure Chhota Shigri’s mass.

Their findings, shared with Reuters, revealed that the best-studied glacier in the Himalayas had experience­d its worst year on record; Chhota Shigri lost three times as much mass in 2022 compared with its 2002 to 2022 yearly average.

“The impacts are already visible as the glacier is thinning and retreating,” said Farooq Azam, a glaciologi­st at the Indian Institute of Technology Indore who monitors Chhota Shigri.

This will be “impactful to downstream water availabili­ty in the near future”, he said.

Satellite observatio­ns also show the glaciers in the Himalayas are in a state of overall decline.

“The ice is really melting significan­tly during the last decades – mass loss is accelerati­ng,” said Tobias Bolch, a glaciologi­st with Graz University of Technology in Austria.

From 1990 to 2015, glacier coverage in the Himalayas shrank by about 11 per cent, according to a July 2022 study.

During the same time period, Himalayan glacial lakes increased by about nine per cent in number, and 14 per cent in area. More than 200 lakes now pose a very high hazard to Himalayan communitie­s, according to 2022 research.

Pakistan is home to more than 7,000 glaciers in the spectacula­r Himalaya, Hindu Kush and Karakoram mountain ranges, more than anywhere else on earth outside the two poles.

Last summer, on the heels of a two-month heat wave and during sustained rains that followed, raging torrents from melting glaciers in northern Pakistan ripped up thousands of kilometres of roads and railway tracks, destroyed bridges, and washed away entire villages.

Half of the earth’s 215,000 glaciers and a quarter of their mass will melt away by the end of the century. That will occur even if global warming can be capped at 1.5ºC, the ambitious Paris Agreement target that many scientists now say is beyond reach, a recent study found.

Over the past century, a third of global sea-level rises came from glacier melt, according to earlier research.

 ?? ?? CLIMATE CHANGE WARNING: Local use a temporary footbridge after a lake outburst because of a melting glacier swept away the main bridge (pictured in the background) in Hassanabad village of Pakistan’s Gilgit-Baltistan region in June last year
CLIMATE CHANGE WARNING: Local use a temporary footbridge after a lake outburst because of a melting glacier swept away the main bridge (pictured in the background) in Hassanabad village of Pakistan’s Gilgit-Baltistan region in June last year

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