Retreating glaciers in the Himalayas are not only dangerously filling up glacial lakes but they are also causing other hazards that are not being monitored, scientists have warned.
The recent flash flood disaster in India’s Uttarakhand state, they say, is the latest example of such a perilous knowledge gap.
The Himalayas have the largest number of glaciers on Earth outside the poles and they have lost billions of tonnes of ice due to accelerated melting caused by global warming.
“There is simply no comprehensive understanding of what actually is happening in terms of such hazards,” said Professor Jeffrey Kargel, a senior geologist in the US who has researched a number of disasters in the Himalayas and who is also looking into the Uttarakhand disaster.
“We are just reactive when incidents like what happened in Uttarakhand happen. We are not monitoring the glaciers with such hazard attributes, at least not the majority of them.”
Dangers of retreating glaciers
Experts say when glaciers retreat or thin out, some of them can become dangerous. For instance, in some cases, remaining ice of retreated glaciers can hang perilously on steep walls of mountains and can collapse at any time.
Scientists say such events can also block rivers and rivulets below that eventually burst, sweeping away everything in their path – just like what seems to have happened in Uttarakhand recently, according to preliminary findings.
But they say they don’t know where exactly such glacier-related dangers are lurking and which human settlements and infrastructure downstream are under threat.
The difficult geography of the Himalayas makes such monitoring extremely challenging, they add.
“There are more than 50,000 glaciers in the Himalayas and the Hindu Kush region and only 30 of them are being closely observed, including field studies,” said Muhammad Farooq Azam, a glaciologist with the Indian Institute of Technology, Indore.
“Only around 15 of those studies have been published. We need to be observing our glaciers more closely, particularly because so many factors are at play.”
Scientists say as the youngest mountain ranges in the world, the Himalayas are still growing and earthquakes often destabilise their slopes.
Changing snowfall and rainfall patterns in the wake of climate change make the mountains more vulnerable, they added.
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