Climate change in high-mountain regions is associated with significant change in vegetation dynamics, snow coverage, glacier mass balance, and permafrost, which have led to profound changes in both hydrological regimes and their extremes, making the “water towers” vulnerable. Hydrological regimes and their responses to climate change and its associated cryospheric change in high-mountain regions are quite complicated due to intertwined interactions among multiple processes (i.e. ice melting, snow melting, permafrost degradation, and rainfall–runoff) as well as flow pathways. Critical knowledge gaps and large observational uncertainties pose additional challenges for predicting hydrological response to the co-evolution of climate, cryosphere, and biosphere in the high-mountain regions globally.

This special issue calls for a wide range of submissions across a series of disciplines with a hydrological, climatological, and cryospherical perspective across global or regional high-mountain regions, with a focus on exploring the co-evolutional mechanisms of the soil–ice–snow–vegetation system in the context of climate change and their impacts on both hydrological regimes and their extremes. Potential submissions can be in but are not limited to the following areas:

• review of the important issues and methodologies in global or regional high-mountain hydrological studies;
• novel approaches to studying hydrological response to climate and land surface property changes over alpine regions;
• spatial, seasonal/temporal, or elevational patterns and co-evolution mechanisms in vegetation, snow, glaciers, and permafrost as well as their response to climate change and impacts on hydrology in high-mountain regions;
• global or regional climate change and its impacts on the biosphere, cryosphere, and hydrosphere in high-mountain regions;
• observations and projections of changes and variability in hydrological regimes and their extremes in global or regional high-mountain regions;
• integrated database of hydrological and climatological variables in global or regional high-mountain regions.