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

Subject :Environment

Section :Climate Change

In the news:

A recent study mapped over 100 rock glaciers in the Kashmir Himalayas, revealing signs of movement or melting in these permafrost structures.

Details:

Termed ‘active glacial rocks,’ these formations are potentially linked to natural disasters as the region experiences warming.
While permafrost research is extensive in areas like Greenland and Alaska, knowledge about Himalayan rock glaciers remains limited.

Active glacial rocks:

Rock glaciers form when debris-covered ice transforms due to receding or thawing glaciers.
The process might have accelerated during warmer periods in the Earth’s recent interglacial era.
These structures are often mistaken for regular ground, leading to settlements being planned on unstable terrain.
The melting permafrost poses risks to nearby communities and infrastructure, as seen in Canada’s Nunavik area.
Researchers identified these rock glaciers using satellite images and field visits, constructing a ‘Permafrost Zonation Map’ pinpointing 207 rock glaciers across 50 square kilometres in the Jhelum basin. They categorized these formations as ‘active’ or ‘relict’ based on permafrost status.
Reports highlight the shift from glaciers to rock glaciers in the Kashmir valley’s southwestern parts, indicating a serious transition in glaciation stages.
Experts anticipate rock glaciers will become more common due to increased debris concentrations in melting glaciers, a trend already observed in the Jhelum basin’s debris-covered glaciers.
This underscores the importance of mapping permafrost distribution in the Himalayan region due to the potential risks associated with melting permafrost in rock glaciers.

Dangers posed & a benefit:

The study identifies dangers posed by rock glaciers, particularly near glacial lakes like Chirsarand Bramsar Lakes, increasing the risk of glacial lake outburst floods (GLOFs).
These permafrost formations, located at steep slopes, could lead to slope failures and subsequent melting, potentially causing GLOFs and more frequent landslides.
The presence of waterbodies resembling ‘thermokarst lakes’ suggests hidden permafrost in the Jhelum Basin.
- Thermokarst is a type of terrain characterised by very irregular surfaces of marshy hollows and small hummocks formed as ice-rich permafrost thaws. The land surface type occurs in Arctic areas, and on a smaller scale in mountainous areas such as the Himalayas and the Swiss Alps. These pitted surfaces resemble clusters of small lakes formed by the dissolution of limestone in some karst areas.
These permafrost structures hold significant water volumes, approximately a trillion litres across the Jhelum basin, amid dwindling water sources.