Glaciers are melting at unprecedented rates across the Hindu Kush Himalayan mountain ranges and could lose up to 80 per cent of their volume by 2100 if greenhouse gas emissions are not sharply reduced, according to a report.
The report on June 20 from the Kathmandu-based International Centre for Integrated Mountain Development warned that flash floods and avalanches would grow more likely in coming years, and that the availability of fresh water could be curtailed for nearly two billion people who live downstream of 12 rivers that originate in the mountains.
Ice and snow in the Hindu Kush Himalayan ranges are an important source of water for those rivers, which flow through 16 countries in Asia and provide fresh water to 240 million people in the mountains and another 1.65 billion downstream.
“The people living in these mountains who have contributed next to nothing to global warming are at high risk due to climate change,” said Amina Maharjan, a migration specialist and one of the report’s authors. “Current adaptation efforts are wholly insufficient, and we are extremely concerned that without greater support, these communities will be unable to cope.”
Cryosphere worst affected
Various earlier reports have found that the cryosphere—regions on Earth covered by snow and ice—are among the worst affected by climate change. Recent research found that Mt Everest’s glaciers, for example, have lost 2,000 years of ice in just the past 30 years.
“We map out for the first time the linkages between cryosphere change with water, ecosystems, and society in this mountain region,” Maharjan said.
Among the key findings from the report are that the Himalayan glaciers disappeared 65 per cent faster since 2010 than in the previous decade, and that reducing snow cover due to global warming will result in reduced fresh water for people living downstream. The study found that 200 glacier lakes across these mountains are deemed dangerous, and the region could see a significant spike in glacial lake outburst floods by the end of the century.
“As it gets warmer, ice will melt, that was expected, but what is unexpected and very worrying is the speed,” lead author Philippus Wester said. “This is going much faster than we thought.”
‘Unprecedented and largely irreversible’
The study found that communities in the mountain regions are being affected by climate change far more than those in many other parts of the world. It says changes to the glaciers, snow, and permafrost of the Hindu Kush Himalayan region driven by global warming are “unprecedented and largely irreversible”.
Effects of climate change are already felt by Himalayan communities, sometimes acutely. Earlier this year the Indian mountain town of Joshimath began sinking and residents had to be relocated within days.
“Once ice melts in these regions, it’s very difficult to put it back to its frozen form,” said Pam Pearson, director of the International Cryosphere Climate Initiative, who was not involved with the report.
She added, “It’s like a big ship in the ocean. Once the ice starts going, it’s very hard to stop. So, with glaciers, especially the big glaciers in the Himalayas, once they start losing mass, that’s going to continue for a really long time before it can stabilise.”
Pearson said it is extremely important for Earth’s snow, permafrost, and ice to limit warming to the 1.5 degrees Celsius agreed to at the 2015 Paris climate conference. “I get the sense that most policymakers don’t take the goal seriously but, in the cryosphere, irreversible changes are already happening,” she said.
The world has warmed an average of nearly 1.2°C since the mid-1800s, unleashing a cascade of extreme weather, including more intense heatwaves, more severe droughts, and storms made more ferocious by rising seas.
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Thus, even if global warming is limited to the 1.5 to 2°C from pre-industrial levels agreed to in the Paris climate treaty, the glaciers are expected to lose a third to a half of their volume by 2100, the report said.
“It underscores the need for urgent climate action,” Wester said. “Every small increment will have huge impacts and we really, really need to work on climate mitigation... that is our plea.”
Wester said improving technologies and previously classified high-resolution satellite imagery meant predictions could be made with a good degree of accuracy.
(with inputs from AP and AFP)