Hindu Kush Himalayan glaciers could lose up to 80 per cent of their current volume by 2100 in a business-as-usual scenario, according to the report
The Hindu Kush Himalayas (HKH) have seen a 65 per cent faster loss of glacier mass, according to a new report from International Centre for Integrated Mountain Development (ICIMOD).
The glaciers lost a mass of 0.28 metres of water equivalent per year (m w.e.) between 2010 and 2019 compared to 0.17 (m w.e.) per year between 2000 and 2009, the Water, Ice, Society, and Ecosystems in the Hindu Kush Himalaya (HI-WISE) report noted.
The Karakoram range, which was known to be stable, has also started showing a decline in glacier mass, losing 0.09 m w.e. per year during 2010-2019.
“The glaciers of the Hindu Kush Himalaya are a major component of the Earth system. With two billion people in Asia reliant on the water that glaciers and snow here hold, the consequences of losing this cryosphere are too vast to contemplate. We need leaders to act now to prevent catastrophe,” Izabella Koziell, ICIMOD’s deputy director general, said in a statement.
Glaciers occupy an area of approximately 73,173 square kilometres (km2) in the HKH.
Ice and snow in the HKH, according to the report, are an important source of water for 12 rivers that flow through 16 countries in Asia. About 240 million people are in the mountains and 1.65 billion downstream are dependent on them.
The average temperature in the region has increased by 0.28°C per decade between 1951 and 2020.
Nine out of 12 river basins have witnessed increased warming rates at higher elevations. The strongest impacts are being felt in the Brahmaputra, Ganges, Yangtze, and Indus Basins.
In a business-as-usual scenario, HKH glaciers could lose up to 80 per cent of their current volume by 2100, the report highlighted.
Further, a quarter of snow cover could be lost under a high emissions scenario. The report quoted a study that predicted a decline in snowfall by 30-50 per cent in the Indus Basin, 50-60 per cent in the Ganges, and 50-70 per cent in the Brahmaputra between 2070 and 2100 compared to the average snowfall between 1971 and 2000.
The report also highlighted the limited available information on permafrost — ground that remains at or below 0°C for at least two consecutive years — in the Hindu Kush region.
Even with scanty information, scientists are seeing a decreasing trend. Studies have estimated that western Himalaya lost 8,340 square km of permafrost area between 2002 and 2004 and 2018 and 2020, and about 965 square km of area disappeared in Uttarakhand Himalaya between 1970 and 2000 and 2001 and 2017.
The researchers point out gaps in understanding the possible impacts of thawing permafrost due to climate change.
This is important as the loss of permafrost could lead to infrastructure damage, costing the world several billion dollars.
If permafrost thaws, the ground becomes much less stable. “We are already seeing the effects of this, for example in landslides caused by thawing permafrost,” Miriam Jackson, ICIMOD senior cryosphere specialist and IPCC lead author (SROCC) told Down To Earth.
The report calls for more measurements, especially in regions where road construction projects are in the pipeline and if people reside near permafrost.
The region is expected to see an increase in floods and landslides. These hazards, the report noted, increase the risk of loss and damage, including population displacement.
The authors of the report stress that the mountain population are extremely vulnerable to the changing cryosphere (the frozen water part of the Earth system) and that urgent adaptation measures need to be adopted.
“Current adaptation efforts are wholly insufficient to meet the challenges posed by cryospheric change and the extreme events that we now know with a high degree of certainty will hit these already vulnerable communities with greater magnitude and complexity. We are extremely concerned that without greater support, these communities will be unable to cope. Adaptation needs to be urgently scaled up,” Amina Maharjan, senior livelihoods specialist at ICIMOD, said in a statement.
The biodiversity of the region — 40 per cent of which is under protected areas — is dependent on the cryosphere as it is an important source of water for maintaining ecosystem health, supporting biological diversity, and providing ecosystem services.
With climate change driving glacier mass loss, reduction in snow cover, shrinking of permafrost area, changes in hydrology, and increased natural hazards and disasters, cascading impacts on the ecosystem can be seen.
Researchers have documented changes such as species migrating to higher elevations, ecosystem degradation and changes, decrease in habitat suitability, species decline and extinction, and invasion by alien species.
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