Abstract Due to the abundance of freshwater outside the polar ice sheets, the Himalayas have been referred to as the "Third Pole" of the planet. Many perennial rivers can be found there, where permanent ice fields and seasonal snow cover melt. A warming climate poses a threat to the glaciers, especially the smaller ones. Due to a lack of long-term records, the dynamic response of medium-sized Himalayan glaciers to recent climate variability is still poorly limited. Using Sentinel-1 SAR velocity mapping, elevation differencing, and other methods, this work provides an eight-year-scale evaluation of glacier surface elevation and velocity variations throughout Himachal Pradesh from 2017 to 2025. With a mean elevation loss rate of −0.32 ± 0.06 m yr−1 and a velocity decrease from 0.15 ± 0.07 m day−1 in 2017 to 0.08 ± 0.02 m day−1 in 2025, the results show a pattern of glacier thinning throughout the area. The substantial relationship between surface lowering and ice-flow slowdown is confirmed by a statistically significant negative correlation (R2 = 0.861) between normalized elevation difference and velocity difference. Results from remote sensing are supported by field observations of Karcha glacier, which show terminal disintegration, debris build up, and gradual standstill. These results show that integrated small and medium-sized glaciers (< 10 km2) are now rapidly losing mass and are in danger. The work emphasizes the need for ongoing satellite-based monitoring to limit glacier response to regional climate forcing and the rapid deterioration of the western Himalayan cryosphere. Research Highlights <UnorderedList Mark="Bullet"> <ItemContent> This study provides the first region-wide, multi-temporal assessment (2017–2025) of small and medium-sized glaciers in Himachal Pradesh, addressing a key observational gap in Himalayan cryosphere research. </ItemContent> <ItemContent> Results reveal widespread glacier thinning (−0.32 ± 0.06 m yr−1) and a marked decline in surface velocity (from 0.15 ± 0.07 to 0.08 ± 0.02 m day−1), indicating accelerated mass loss and transition toward dynamically stagnant glacier regimes. </ItemContent> <ItemContent> A strong negative correlation (R2 = 0.861) between elevation changes and velocity demonstrates that glacier thinning directly drives ice-flow slowdown through reduced driving stress, highlighting a key process controlling glacier dynamics. </ItemContent> <ItemContent> Field observations and remote sensing jointly show increasing debris cover, crevasse formation, and snout disintegration, confirming enhanced glacier degradation and signaling potential impacts on regional hydrology, hazards, and water security. </ItemContent> </UnorderedList>

Fate and state of small and medium-sized glaciers of Himachal Pradesh, India: a geospatial-based perspective

期刊论文
发表日期：

2026年4月21日

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Shubham Bhattacharjee,
Rahul Dev Garg,
Arvind Chandra Pandey

摘要

Abstract

Due to the abundance of freshwater outside the polar ice sheets, the Himalayas have been referred to as the "Third Pole" of the planet. Many perennial rivers can be found there, where permanent ice fields and seasonal snow cover melt. A warming climate poses a threat to the glaciers, especially the smaller ones. Due to a lack of long-term records, the dynamic response of medium-sized Himalayan glaciers to recent climate variability is still poorly limited. Using Sentinel-1 SAR velocity mapping, elevation differencing, and other methods, this work provides an eight-year-scale evaluation of glacier surface elevation and velocity variations throughout Himachal Pradesh from 2017 to 2025. With a mean elevation loss rate of −0.32 ± 0.06 m yr⁻¹ and a velocity decrease from 0.15 ± 0.07 m day⁻¹ in 2017 to 0.08 ± 0.02 m day⁻¹ in 2025, the results show a pattern of glacier thinning throughout the area. The substantial relationship between surface lowering and ice-flow slowdown is confirmed by a statistically significant negative correlation (R² = 0.861) between normalized elevation difference and velocity difference. Results from remote sensing are supported by field observations of Karcha glacier, which show terminal disintegration, debris build up, and gradual standstill. These results show that integrated small and medium-sized glaciers (< 10 km²) are now rapidly losing mass and are in danger. The work emphasizes the need for ongoing satellite-based monitoring to limit glacier response to regional climate forcing and the rapid deterioration of the western Himalayan cryosphere.

Research Highlights

This study provides the first region-wide, multi-temporal assessment (2017–2025) of small and medium-sized glaciers in Himachal Pradesh, addressing a key observational gap in Himalayan cryosphere research.

Results reveal widespread glacier thinning (−0.32 ± 0.06 m yr⁻¹) and a marked decline in surface velocity (from 0.15 ± 0.07 to 0.08 ± 0.02 m day⁻¹), indicating accelerated mass loss and transition toward dynamically stagnant glacier regimes.

A strong negative correlation (R² = 0.861) between elevation changes and velocity demonstrates that glacier thinning directly drives ice-flow slowdown through reduced driving stress, highlighting a key process controlling glacier dynamics.

Field observations and remote sensing jointly show increasing debris cover, crevasse formation, and snout disintegration, confirming enhanced glacier degradation and signaling potential impacts on regional hydrology, hazards, and water security.