A new study has found that the rapidly changing climate has weakened swaths of Himalayan glaciers and formed unstable chunks of ice that hang from steep slopes and could explode, leading to a series of environmental disasters in the state of Uttarakhand.
The study – conducted by the Indian Institute of Science, the Indian Institute of Technology, Bhubaneswar, and the Defense Geoinformatics Research Establishment – mapped 219 of these pieces, known as “hanging glaciers” in the Alaknanda Basin. These glaciers occupy steep slopes, with about 30% of them in the upper Alaknanda Basin, including areas such as Badrinath in Uttarakhand, said the study published on Friday in the journal Nature’s Natural Hazards.
Rapid settlement growth increases vulnerability to disasters
These hanging glaciers, coupled with the rapid rise in human settlements in the environment of the Alaknanda Basin, have increased the exposure of the population and nearby infrastructure to significant risks, especially glacial disasters.
The analysis showed that settlements in the basin expanded by 616% over the past five decades, contributing to a 57% decrease in agricultural land and a 33% decrease in barren land. Built-up areas are expected to increase from about 8,000 square meters in 2000 to about 152,000 square meters by 2030. The number of people expected to be exposed to these risks is expected to increase from about 380 to 8,500 in the same period.
The rising temperature of the Himalayas is accelerating the melting of glaciers
Glaciers in high alpine environments are particularly sensitive to climate changes. Temperature rise in the Himalayas has exceeded the global average over the past two decades, shrinking glaciers and cutting off glacier tributaries from their “trunks.” These phenomena could trigger a cascade of disasters, such as last year’s Darali floods, which scientists say were caused at least to some extent by unstable glaciers.
“The high-altitude regions of the Himalayas are experiencing significant changes due to climate change… This research provides a unique dataset on hanging glaciers and potential areas that could be affected,” said Anil V. Kulkarni, Distinguished Visiting Scientist at the Divesha Center for Climate Change, IISc. He added that the data is vital for planners to systematically develop and improve the safety of mountain communities.
The Alaknanda basin contains about 848 glaciers distributed among the sub-basins: Mandakini, Pindar, Meena Nala, Nandakini, Vishnuganga, Rishiganga, Dhauliganga and Girthiganga. The basin hosts several pilgrimage sites such as Kedarnath, Badrinath and Hemkund Sahib. Major settlements including Joshimath, Chamoli, Tapovan and Manna; Trekking routes like Valley of Flowers, Roopkund and Nanda Devi Base Camp; Hydropower projects such as Vishnuprayag, Tapovan-Vishnugad and Pipalkoti are all located in close proximity to glacial terrain.
A 2023 paper reported 681 avalanche events that killed more than 3,100 people across high mountains in Asia over the past 50 years, including 60 that killed more than 1,400 people in the Indian Himalayas and Nepal. The paper cited the 2015 Gorkha earthquake-triggered avalanche and the 2021 Chamoli rock avalanche in Uttarakhand as examples of disasters caused by hanging glaciers. “Hanging glaciers have enormous potential to cause indirect or secondary hazards,” the newspaper said. “For example, a mass failure caused by hanging glaciers overlooking glacial lakes could cause the lake’s waters to rise and breach its dam, leading to a glacial lake bursting.”
