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In the rapidly warming Himalayas, melting glaciers are creating thousands of alpine lakes, threatening communities scattered across the mountain landscape.
A New York Times story details the August day last year when 100 million gallons of glacial meltwater overflowed and swept into the village of Thame, flooding the medical clinic, school, fields of potatoes and dozens of homes.
Miraculously, no one was hurt.
But the event illustrates the massive threat that melting glaciers present for the region — one of the fastest-warming places on Earth due to climate change.
The problem is the meltwater, reports Jason Gulley, who spent a month trekking through the Everest region. As glaciers shrink, water gathers in earthen bowls where ice once sat, forming lakes.
If loose dirt and rocks around the bowl slide into the water, or a chunk of remaining ice breaks off, that lake water is displaced – and what happens next can be catastrophic.
“Picture doing a cannonball into an aboveground swimming pool,” explained glacial floods expert Daniel Shugar, except instead of a splash, you take out one whole wall of the pool. “It would drain within seconds.”
To get a better picture of the potential damage from these floods, geomorphologists are examining 3D models of valleys before and after the events, measuring how much dirt and rocks the lake water picks up as it gains momentum — turning hundreds of millions of gallons of water into a slurry as thick as wet concrete.
The warming happening here could eventually become catastrophic — not just for alpine villages, but for the billion people who live downstream.
The peaks of the Eastern Himalayas, the tallest in the world, hold so much water that they are known as the world’s “third pole” — the largest store of freshwater on Earth outside of Greenland and the Antarctic ice caps.
As glaciers recede and monsoon seasons shift, some glacial-fed rivers are drying up while others face more frequent and severe floods. Meanwhile, swaths of forest are lost to deforestation each year. For the people who live here, these changes are devastating — threatening their farms, fisheries and access to clean water, leaving their way of life in the balance.
What can help slow this deluge and capture some of the deadly sediment?
Trees. A lot of them.
Mountains to Mangroves — a regional effort supported by Conservation International — aims to plant 1 billion trees across the Eastern Himalayas, while protecting and restoring 1 million hectares (2.5 million acres) across Bhutan, India, Bangladesh and Nepal.
Guided by local knowledge, the partnership focuses on ensuring the right trees are planted in the right places, strengthening ecosystems and supporting the communities who depend on them.
As the region confronts the effects of climate change and rapidly warming glaciers, overflowing lakes and flooding events may be unavoidable.
For those living downstream — in the path of the meltwater — restoring degraded and deforested forests might offer the best chance to blunt the worst effects.
