Bhattacharya et al. (2026) Multi-decadal geodetic mass balance, climate sensitivity, and projected glacier response in the Chandra–Bhaga Basin, Western Indian Himalaya (1971–2100)

Identification

• Journal: The Science of The Total Environment
• Year: 2026
• Date: 2026-01-15
• Authors: Atanu Bhattacharya, Ankita Paul, Kriti Mukherjee, Julekha Khatun, Sajid Ghuffar, Tobias Bolch
• DOI: 10.1016/j.scitotenv.2025.181261

Research Groups

• Department of Earth Sciences & Remote Sensing, JIS University, Kolkata, India
• Centre for Data Science, JIS Institute of Advanced Studies & Research, Kolkata, India
• Cranfield Environment Centre, Cranfield University, Bedford, UK
• Department of Space Science, Institute of Space Technology, Islamabad, Pakistan
• Institute of Geodesy, Graz University of Technology, Graz, Austria

Short Summary

This study assesses the multi-decadal geodetic mass balance of glaciers in the Chandra–Bhaga Basin, Western Indian Himalaya, revealing a substantial mass loss of 0.26 ± 0.10 m water equivalent per year from 1971 to 2022, primarily driven by summer temperature. Projections indicate that up to 70% of glacier volume may be lost by 2100, even under a low emission scenario, with small glaciers potentially disappearing before mid-century.

Objective

• Developing a comprehensive multi-decadal (1971–2022) geodetic glacier mass balance record.
• Linking geodetic glacier mass balance with climate variables to reconstruct past and project future mass balance.
• Assessing mass balance sensitivity to individual climate parameters to identify the dominant controls.

Study Configuration

• Spatial Scale: Chandra–Bhaga Basin, Lahaul-Spiti, Western Indian Himalaya (approximately 32.07°N–32.72°N latitude and 77.08°E–77.79°E longitude), spanning a total area of ~4113 km² with a glacierized extent of about 1060 km² (348 glaciers analyzed).
• Temporal Scale: Multi-decadal observations from 1971 to 2022, with future projections extending from 2023 to 2100.

Methodology and Data

• Models used:
  • Principal Component Regression (PCR) model for predicting glacier mass balance.
  • Elevation-dependent sigmoid function to model non-linear glacier thickness change.
  • Photogrammetric methods (Remote Sensing Software Graz (RSG), Corona Stereo Pipeline (CoSP) framework, AMES Stereo Pipeline (ASP)) for Digital Elevation Model (DEM) generation, including semi-global matching (SGM) algorithm.
• Data sources:
  • Satellite data: Declassified Corona (KH-4B) and Hexagon (KH-9) panoramic camera stereo products, SPOT-5, ASTER-L1A, Pleiades DEMs, Cartosat-1 stereo products, Landsat ETM+/OLI, NASA DEM (30 m spatial resolution).
  • Climate data: Coupled Model Intercomparison Project Phase 6 (CMIP6) ensemble mean data (monthly near-surface air temperature and precipitation across SSP126, SSP245, SSP370, SSP585 scenarios), ERA5 Land reanalysis climate data (10 km spatial resolution, 1971–2022), Bhuntar observatory weather station data (1971–2022).
  • Mass balance data: 21 multi-temporal glacier mass balance datasets generated from DEM pairs (1971–2022), supplemented with 7 estimates from existing literature (Hugonnet et al., 2021; Brun et al., 2017; Maurer et al., 2019).
  • Ancillary data: Randolph Glacier Inventory (RGI v7.0), global debris thickness data (Rounce et al., 2021), ice thickness maps (Farinotti et al., 2019).

Main Results

• Glaciers in the Chandra–Bhaga Basin experienced a significant mass loss of 0.26 ± 0.10 m water equivalent per year (m w.e. a−1) from 1971 to 2022.
• The mass loss accelerated notably after 2000, increasing from 0.11 ± 0.08 m w.e. a−1 (1971–2002) to 0.47 ± 0.12 m w.e. a−1 (2002–2022).
• Debris-covered glaciers showed greater ice loss (0.28 ± 0.10 m w.e. a−1) than clean-ice glaciers (0.20 ± 0.12 m w.e. a−1). Small glaciers (<0.5 km²) also lost more mass (0.28 ± 0.11 m w.e. a−1) than the regional average.
• Summer temperature is the most significant control on glacier mass budget, with a sensitivity of −0.49 m w.e. a−1 °C−1 (CMIP6-based). Winter precipitation is positively correlated with glacier mass gain.
• Future projections (2023–2100) indicate substantial increases in glacier mass loss, reaching up to 3.26 m w.e. a−1 by 2100 under the high-emission SSP585 scenario. Even under the low-emission SSP126 scenario, regional glacier volume loss is projected to be approximately 69% by the end of the 21st century.
• Small glaciers (<0.5 km²) are projected to disappear before mid-century due to accelerated ice loss.
• Discrepancies in mass balance sensitivities derived from CMIP6 and ERA5 Land reanalysis data highlight uncertainties in climate datasets for complex mountainous regions.

Contributions

• Developed the first comprehensive multi-decadal (1971–2022) geodetic glacier mass balance record for the Chandra–Bhaga Basin, addressing a critical data gap in the Western Indian Himalaya.
• Established a robust relationship between regional glacier mass balance and combined climate variables using Principal Component Regression, enabling both past reconstruction and future projections under Shared Socioeconomic Pathway (SSP) scenarios.
• Quantified the dominant climate controls on glacier mass balance, identifying summer temperature as the strongest driver and highlighting the complex role of precipitation in this transitional climatic zone.
• Demonstrated the efficacy of long-term satellite-based geodetic data as a scalable and reliable alternative to sparse in-situ measurements for understanding glacier–climate interactions in data-scarce mountain regions.
• Provided critical insights into the temporal variability and heterogeneous responses of glaciers, enhancing understanding for climate adaptation strategies and sustainable water management in glacier-dependent communities.

Funding

• Anusandhan National Research Foundation (ANRF), Department of Science & Technology (DST), India, under Core Research Grant (CRG) (CRG/2021/002450).
• Ministry of Earth Sciences (MoES), India (MoES/INDO-SWISS/4/2022-PC-I).
• Women in Science and Engineering Fellowship for Ph.D. (WISE-PhD) under WISE-KIRAN Division, Department of Science & Technology (DST), Ministry of Science and Technology, Govt. of India (File no. DST/WISE-PhD/EA/2024/43).

Citation

@article{Bhattacharya2026Multidecadal,
  author = {Bhattacharya, Atanu and Paul, Ankita and Mukherjee, Kriti and Khatun, Julekha and Ghuffar, Sajid and Bolch, Tobias},
  title = {Multi-decadal geodetic mass balance, climate sensitivity, and projected glacier response in the Chandra–Bhaga Basin, Western Indian Himalaya (1971–2100)},
  journal = {The Science of The Total Environment},
  year = {2026},
  doi = {10.1016/j.scitotenv.2025.181261},
  url = {https://doi.org/10.1016/j.scitotenv.2025.181261}
}