Editorial: "Our Changing Cryosphere-Understanding its Dynamics, Hazards, and Implications for Water Security"

Rayees Ahmed^1*Ashim Sattar²Gowhar Farooq Wani³Riyaz Ahmad Mir⁴

• ¹Indian Institute of Science (IISc), Bangalore, India
• ²Indian Institute of Technology Bhubaneswar, Bhubaneswar, India
• ³University of Kashmir, Srinagar, India
• ⁴National Institute of Hydrology, Roorkee, India

The Earth's cryosphere, comprising glaciers, ice caps, seasonal snow cover permafrost, and glacial lakes, represents a key component of the Earth system, deeply intertwined with climatic, hydrological, and ecological processes. It plays a central role in regulating the energy balance, sustaining water supply systems, and supporting biodiversity, particularly in high-mountain and polar regions (Hock et al., 2019). Meltwater from seasonal snowpacks and glaciers greatly influences downstream river flows in snow and glacier-fed watersheds, supplying water for hydropower, agriculture, ecosystems, and domestic needs (Immerzeel et al., 2020;Azam et al., 2021). However, the cryosphere is changing rapidly and dramatically as a result of rising global temperatures. There is currently ample evidence of glacier recession, permafrost degradation, decreased snow cover, and the growing number of moraine-dammed glacial lakes in cryosphere-dominated regions (Zemp et al., 2015;Bolch et al., 2019). These changes are leading to a range of interlinked impacts, including shifts in the timing and magnitude of meltwater discharge, changes in river hydrology and water chemistry and a rise in cryospheric hazards like rock-ice avalanches, Glacial Lake Outburst Floods (GLOFs), and thermokarst processes (Harrison et al., 2018;Emmer et al., 2022;Sattar et al., 2025). These growing hazards have been shown to pose substantial risks to lives, livelihoods, and critical infrastructure in several high mountain regions, whereas the shifting availability of water resources may further challenge the resilience of some mountain communities-particularly those already facing demographic pressures, land-use changes, and limited adaptive capacity (Ahmed et al., 2025). The impact of cryosphere-climate interactions on hydrology, hazard dynamics, and long-term water security is still not well understood scientifically in many regions, particularly in data-scarce mountain environments such as the Himalayas and the Tibetan Plateau.To address these pressing scientific and societal challenges, this Research Topic (RT) titled "Our Changing Cryosphere-Understanding its Dynamics, Hazards, and Implications for Water Security" was conceived with the aim of improving our knowledge of cryosphere processes and their implications through interdisciplinary approaches. The RT mainly focused on advancing our understanding of cryosphere-hydrosphere-climate interactions, evaluating cryospheric hazards and risk reduction strategies, improving hydrological and thermal models for glacierized environments, and supporting sustainable water management in regions reliant on seasonal snow and ice melt.The contributions submitted under this RT cover important facets of the evolving cryosphere and include from a variety of approaches and geographical regions. These studies offer new insights into how physical, environmental, and climatic factors collectively shape cryospheric processes and their downstream implications. Examples include modeling the thickness of debris on Himalayan glaciers, assessing groundwater recharge delays caused by seasonally frozen ground in the Tibetan Plateau, and examining hydrochemical shifts in Alaskan glacial rivers as well as isotopic variability in snow and glacier melt in Indian catchments. In the following sections, we concisely summarize the original research articles published under this Research Topic and reflect on the key findings, scientific contributions, and implications of each study. investigates supraglacial debris thickness on the Hoksar Glacier in the Kashmir Himalaya using empirical and thermal resistance approaches. The presence of debris on glacier surfaces has a profound effect on the thermal regime and melt dynamics; hence, accurate thickness 47 estimation is essential for hydrological modeling. The utilizes thermal remote sensing data from Landsat 48 OLI and AST08 along with ERA5 reanalysis datasets. An empirical relationship was developed between field-49 measured debris thickness and satellite-derived surface temperature, and a thermal resistance method was 50 applied using an energy balance model. Field measurements recorded an average debris thickness of 18.9 ± 51 7.9 cm. The empirical approach underestimated debris thickness by 12-28%, whereas thermal resistance 52 method showed closer alignment with field data (deviation ~11%