Himalayan glaciers are highly sensitive to climate change and are rapidly shrinking, posing a big threat to the populations that rely on them, according to scientific explanations. Besides the ecosystem services that the glaciers provide, their melting increases the risk of runoffs and floods as recently seen with the Uttarakhand glacier disaster that claimed 26 lives and 197 people still reported missing with rescue operations underway.
The science behind what is currently happening in the Himalayas was forecasted by the Intergovernmental Panel on Climate Change (IPCC) in its 2019 report that says glaciers would retreat in the upcoming years, causing landslides and floods.
Himalayan glaciers play an important role in South Asia, providing drinking water and water resources for agriculture, hydropower and biodiversity.
Glaciers in the Hindu Kush Himalaya region are a crucial water supply for the 240 million people who live in the region, including 86 million Indians, roughly the equivalent of the country's five biggest cities combined.
Another comprehensive report two years ago, the Hindu Kush Himalaya Assessment, coordinated by the International Centre for Integrated Mountain Development (ICIMOD) notes that eastern Himalaya glaciers have tended to shrink faster than those in central and western Himalaya.
"While there is still some confusion as to what exactly caused the flood in Uttarakhand, we are working closely with our partners on the ground to understand what happened in this particular instance," ICIMOD Director General Pema Gyamtsho said on Monday.
ICIMOD develops and shares research, information and innovations to empower people in the eight regional member countries of the Hindu Kush Himalaya region -- Afghanistan, Bangladesh, Bhutan, China, India, Myanmar, Nepal and Pakistan.
Sounding an alarm, a 2019 discussion paper by The Energy and Resources Institute (TERI) notes the warming rate over the Himalayan region is projected to increase in the range of 0.5 degrees to one degree Celsius by 2020s and one to three degrees by mid-century.
However, the warming rate is not uniform either spatially or temporally, it says.
However, a 2017 study published in Nature warns that even if global temperature is kept below 1.5 degrees, around 35 per cent of the ice mass stored in the high mountains of Asia will be lost.
It says that number could increase up to 65 per cent in a scenario of high greenhouse gas emissions.
Describing the Himalayas a water tower, Jawaharlal Nehru University's School of Environmental Science Professor A.P. Dimri said with increasing global warming, the upper reaches of the Himalayas are warming faster, leading to more rapid melting of the glaciers.
"This has resulted in an increasing number of glacier lakes, which are formed by water melting from the ice caps and accumulating at the mouth or snout of the glacier. These lakes also become reservoirs of ice and moraine debris. With an increase in this phenomenon, the breach of glacier lakes poses a severe threat to the communities living downstream."
With the Himalayan states prone to flash floods and landslides, this disaster prompted calls by scientists and experts for a review of hydropower projects in the ecologically sensitive mountains.
This deadly flood-hit two hydroelectric dams, claiming most of the victims were workers on the power projects.
Centre for Policy Research Senior Fellow Manju Menon said: "One of the most unfortunate outcomes of the climate policy discourses globally has been a reacceptance of large dams by governments as a viable non-fossil fuel source of energy.
"In India, we had reached a point when massive social and environmental mobilisations on large dams underlined how these structures wastewater instead of conserving it and offering false developmental solutions. This reacceptance is ironic because climate change has also made hydrological flows in the Himalayas erratic and unpredictable, in terms of the impacts on glaciers and monsoon patterns.
"Therefore, planning and implementing large engineering projects on Himalayan rivers is fraught with great risks. Most scholars of Himalayan rivers have been warning about these risks for decades, but the environmental impact assessment for these projects withhold or underplay this information so that projects get approved."
An analysis by the UN University (UNU) said by 2050 most people on earth will live downstream of tens of thousands of large dams built in the 20th century, many of them already operating at or beyond their design life, putting lives and property at risk.
The report, "Ageing water infrastructure: An emerging global risk", by the UNU's Canadian-based Institute for Water, Environment and Health, released last month said most of the 58,700 large dams worldwide were constructed between 1930 and 1970 with a design life of 50 to 100 years, adding that at 50 years, a large concrete dam "would most probably begin to express signs of ageing".
It says climate change will accelerate the dam ageing process.