High-latitude regions are experiencing amplified anthropogenic global warming. Cryospheric changes (e.g. permafrost thaw, snow and ice accumulation, and melt) are strongly coupled with the hydrologic cycle and severely impact the amount and seasonality of groundwater recharge and streamflow generation and associated biogeochemical cycling. These widespread changes, in turn, affect ecological and human systems, with impacts evident even in the ocean. This special issue aims to foster knowledge exchange across communities to gain a better understanding of coupled processes between the cryosphere, hydrology, ecosystems, and humans. It encompasses contributions on topics related to cold-region hydrology with a focus on inter- and transdisciplinary approaches, particularly targeting the following aspects:

• climate-change-induced cryospheric alterations and impacts on the water cycle in northern environments, e.g. changes in the snowpack, glacier recession, permafrost thaw, stream discharge, lake size, and wildfires;
• interdisciplinary research that furthers our understanding of the nexus between hydrological, biogeochemical, and ecosystem processes in cold-region environments;
• the impacts of current (e.g. mining, logging, dam building) and past (e.g. peatland drainage/restoration) land-use changes in high-latitude regions;
• transdisciplinary research, including knowledge of Indigenous communities and other interested parties, ideally aimed at sustainable co-development of climate change adaptation and mitigation strategies;
• studies providing open tools for the development and testing of transposable models in cold-region environments;
• studies providing information on or presenting new tools for the improvement and standardization of measurement techniques and network design in northern regions.