Climate Change

Over 100 active permafrost structures identified in Jhelum basin, can cause catastrophic disasters in future: Study

Active rock glaciers in Kashmir Himalayas also hold significant volumes of water, which underlines the need to explore their hydrological potential further

By Preetha Banerjee
Published: Tuesday 09 January 2024
Photo for representation: iStock

The Kashmir Himalayas are dotted with permafrost structures called ‘rock glaciers’, with significant ice volumes within, a new study mapped.

More than 100 of these had ridges and bulges on their body, which indicates that the permafrost in them has started moving or melting, said the report's lead author, Remya, S N Assistant Professor from the Amrita School for Sustainable Futures, Amrita Vishwa Vidyapeetham, Kerala. These are called ‘active glacial rocks’ and may contribute to natural disasters as the region warms. 

Research on permafrost, which are thick ground layers frozen for at least two years, is at an advanced stage in places like Greenland, Alaska and Siberia. But little is known about the rock glaciers of the Himalayas. 

In several mountainous areas of the world, rock glaciers are prominent due to climate change. These structures hold ice-rich permafrost within them, according to Remya and her national and international collaborators. The report was published in the American Geophysical Union’s Earth and Space Science journal and was co-authored by scientists from the Geological Survey of India, Indian Institute of Technology Bombay-Monash Research Academy, Northumbria University, the United Kingdom, Indian Space Research Organisation Headquarters and Indian Institute of Science, Bangalore. 

Spatial distribution of active and relic rock glaciers in Jhelum Basin

Source: A Framework to Identify Rock Glaciers and Model Mountain Permafrost in the Jhelum Basin, Kashmir Himalaya, India

Rock glaciers typically form in mountainous regions where there is a combination of permafrost, rock debris, and ice. One common scenario involves a pre-existing glacier that accumulates debris and rocks as it moves. Over time, if the glacier recedes or thaws, the debris-covered ice can transform into a rock glacier. This process may have been sped up in the last five decades of the Earth’s current interglacial period, when the warmer periods have become intense, the author noted. Field measurements confirmed that these rock glaciers occur in highly elevated regions with steep slopes, the researchers wrote in the study.

To the naked eye, the rock glaciers look like regular ground, and habitations are often planned on them. But they require a geomorphological view for proper identification, Remya noted.

With the ongoing warming of the world, the melting permafrost makes these areas unstable, posing risks to nearby settlements and critical infrastructure. Such a situation is unfolding in Canada. The Nunavik area in Quebec was mostly built on permafrost ground many years ago. In the last decades, the ice in the underlying layers began to melt due to global warming, increasing the frequency of mudslides and other dangers. The area may be rendered uninhabitable in the near future. The local communities have 10-30 years ‘at the most’ to adapt, a news report published by the Canadian Broadcasting Corporation in 2023 quoted experts as saying. 

Since there is still not much known about them in the Himalayan region compared to other part of the globe. This makes studies that map permafrost distribution in the region most important, Remya said.

She and her team studied satellite images and visited the Jhelum basin to identify rock glaciers. They used a statistical model based on topographic and climatic variables like temperature, solar radiation and slope aspect to build a ‘Permafrost Zonation Map’, pin-pointing around 207 rock glaciers spread over 50 square kilometres.

These were then classified as ‘active’ or ‘relict’ to indicate the status of permafrost within them, identified by the appearance of the rock surfaces, among other things.

“The Kashmir valley is facing deglaciation, in general, however, it is clearly the south western parts, which are showing a very serious transition from glaciers to rock glaciers, which is considered the final stage of glaciation in any region,” a 2022 report published in the Indian Journal of Geosciences noted. 

It added that rock glaciers will become a more common mountain landform in the future, as debris concentrations increase in the melting glaciers with global warming and deglaciation. This, according to the authors, is already being witnessed in the debris-covered glaciers in the Jhelum basin. 

Dangers posed & a benefit

During the field visits for the latest study, the researchers found some rock glaciers near glacial lakes in the region such as Chirsar Lake and Bramsar Lake. These permafrost structures particularly increase the risk of glacial lake outburst floods (GLOFs), warned Remya. 

Chirsar lake, for instance, is located at the terminus of a rock glacier, she added. In case of a slope failure due to which the upper debris layer gives away, the underlying permafrost will be exposed to warming and may eventually melt and feed into the lake, the scientist explained. Several years down the line, this can lead to a GLOF, which causes massive damage in the areas surrounding the lake. 

Evidence of rock glaciers and associated landforms observed during the field visits. (a) Represents upper catchment of Chirsar glacier valley. (b) Represents
the bifurcation of glaciers in progress in the Bramsar glacier valley. (c) Massive glacial boulder on the lateral moraine of Bramsar glacier (d) Paired lateral moraines in
the proglacial area of Chirsar glacier valley (e) Represents a small rock glacier and associated landforms (f) The upper catchment area of a rock glacier. Source: A Framework to Identify Rock Glaciers and Model Mountain Permafrost in the Jhelum Basin, Kashmir Himalaya, India

Moreover, it may also make landslides more frequent with the land on the melting ice becoming loose. The main problem, Remya highlighted, is that all of the rock glaciers were at steep slopes of above 12 degrees, with maximum slopes from 25-65°. This makes them more prone to movement and melting as the stress on them increases. 

Moreover, Remya recalled that during their field trip to Jhelum Basin during summer months, they spotted some waterbodies right in the middle of vegetation some kilometres uphill from Kulgam town, which suggested that there was permafrost underground. These resembled 'thermokarst lakes', she said, becuase there was no stream or glacier to feed them.

But there is a silver lining: These permafrost structures hold large volumes of water and at a time when water sources are fast-disappearing, these can be valuable reserves. “Across the Jhelum basin, active rock glaciers store a trillion litres of frozen water, according to the 2022 report. 

The authors called for more research to understand the distribution of permafrost across the mountainous regions of India, specifically the western Himalayas where the glacial retreat is fast and significant, to assess risks associated with them. “The region's complex topography and limited accessibility make field investigations challenging, highlighting the importance of remote sensing and modelling techniques in studying these frozen landforms,” they added. 

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