KATHMANDU, May 28 (IPS) – In this commentary, IPS looks at GLOF and the risks it poses to local communities as many of the 54,000 glaciers in the Hindu Kush Himalayas (HKH) region shrink due to climate change.
Phu Chhettar Sherpa, who worked as an icefall doctor (Sherpa who fixes ropes for climbers) on Mount Everest for seven years from 2015 to 2021, vividly recalls the fear of flash floods after the 2015 Nepal earthquake.
Sherpa, who is currently working as a trekking guide in the area, said, “I was at Everest Base Camp, and suddenly it started shaking, and at that moment, I saw a body in front of me.” “After some time, there was fear that a glacial lake outburst flood (GLOF) could occur in Imja Glacier Lake, and I was thinking about the families downstream. Fortunately, no GLOF occurred.”
Like the Sherpas, millions of people living in the lower Himalayas and Hindu Kush Himalayas (HKH) regions, including Nepal, are at risk of flash floods that could be unimaginably destructive in a short period of time if the potential floods explode. Dangerous glacial lakes occur, which can be caused by the accumulation of excessive amounts of water due to earthquakes, avalanches, or melting ice.
So what exactly is GLOF?
In general, a GLOF refers to the sudden release of water from a glacial lake, formed by meltwater from a mountain glacier (a river of mountain ice) and impeded by rocks, sediments transported by the glacier, known as moraines. Or a combination of ice and moraine.
Scientists with extensive experience in understanding glaciers and mountain systems generally say that GLOF refers to any flood of water that occurs in a glacier-related lake.
Dr Miriam Jackson, senior cryosphere expert at the International Center for Integrated Mountain Development (ICIMOD), explained: “Lakes can be next to, in front of, or beneath a glacier (a glacier) or actually on top of a glacier (a glacier). .”
“We also use this term when a lake is in a glacial valley but is hundreds of meters from the glacier,” she added.
As climate change affects glaciers, many of them are shrinking and forming lakes.
Jackson explained, “In the Himalayas, many lakes are formed in front of glaciers and are blocked by small ridges called moraines. Moraines are made of material that was pushed forward when the glacier became much larger.”
What causes these lakes to explode?
The main causes of GLOFs are earthquakes, avalanches, and rapid melting of glaciers, causing water to build up in lakes. The root cause of this phenomenon is rising temperatures, and researchers note that the impact of climate change is relatively large in the Himalayas, where glaciers are melting at a rapid rate, creating new lakes and expanding existing ones.
Glaciers may be melting much faster than expected, potentially contributing to sea level rise at a faster rate than previously thought, according to a 2023 research paper published in Nature. Another study published in Nature Climate Change in 2020 analyzed more than 250,000 satellite images to reveal the rapid growth of glacial lakes around the world over the past 30 years, driven by increased meltwater discharge from melting glaciers. Indicates the influence of .
Ines Dussailant, a glaciologist with the World Glacier Monitoring Service who visited the Mount Everest region in the first week of May, expressed concern about the melting of glaciers in the Himalayan region. “The terrain here is a mix of ice and moraine, making it more vulnerable, and newly formed or expanding glacial lakes form weak dams if events such as avalanches, earthquakes or water accumulation exceed their capacity,” she explained. “Dams, explosive flooding can occur.”
How can an avalanche cause a GLOF?
In the third week of April 2024, a Glacial Lake Outburst Flood (GLOF) occurred in Nepal when Birendra Lake, a glacial lake in the Gorkha region, splashed and caused flash flooding in downstream communities. . This is because an avalanche on Mount Manaslu suddenly released water from Lake Birendra, causing flooding in downstream areas.
According to Jackson, an avalanche is a sudden fall of material on a steep slope and can be an avalanche, ice avalanche or rock avalanche.
“Glacier lakes are typically on steep terrain, making it prone to avalanches into the lake,” she explained. “Avalanches can trigger a GLOF by causing material to land in a lake, causing a small movement of water (the recent GLOF of Lake Birendra), or this can trigger a much larger event, such as causing a moraine collapse.”
Why Hindu Kush Himalayas? Does region matter?
Scientists say there are 54,000 glaciers in the Hindu Kush Himalayas (HKH) and almost all of them are shrinking due to climate change.
“This means lakes can form (usually next to or in front of them) and existing lakes can become larger,” Jackson said. “Rivers coming down from high mountains often flow through very narrow valleys. “People live in valleys where GLOFs can occur, but they may not know about glaciers and lake conditions because they are so far upstream.”
Floods may flow down these narrow valleys, bringing with them a lot of rock and sediment. For example, last October, GLOF in Sikkim caused extensive damage, including to a large hydroelectric facility in Chungthang.
“People need to be aware if they live somewhere or frequently travel somewhere where GLOFs may occur,” said Jackson, who was also a scientist on the IPCC report. He said: “If you have an early warning system in place, you can support this by making sure it is well maintained and attending any training provided in this regard.”
The 2020 Inventory of Glacial Lakes report identifies 47 potentially hazardous glacial lakes (PDGLs) within Nepal (21 in Nepal), Tibet Autonomous Region of China (25 in China) and within the Kosi, Gandiaki and Karnali river basins in India. Has confirmed. (one in India). The report said glacial lakes formed by moraines are at risk of collapsing, which could lead to glacial lake outburst floods (GLOFs).
Lowering water levels is one way to mitigate the potential risks posed by GLOFs, as was done in the Imja Tsho (Imaja Lake) glacial lake in the Khumbu region. However, experts believe that the community’s role in reporting potential risks and significant changes is very important.
“If they (local residents) believe there is a risk of GLOF but there is no early warning system in place, they should raise this issue with their local representatives,” Jackson said. “If people are in a high area where they can see glaciers and glacial lakes and they see things changing (e.g. lakes growing), they should report this as soon as possible.”
This feature is published with support from the Open Society Foundations.
IPS UN Secretariat Report
Follow @IPSNewsUNBureau.
Follow the IPS News UN Secretariat on Instagram
© Interpress Service (2024) — All Rights ReservedOriginal source: Interpress Service
