Consequences of Climatic Change for Hydrology in Permafrost Zones

Increasing ${\mathrm{CO}}_2$ concentration in the atmosphere will likely lead to warming and precipitation increase in the permafrost region, though the predicted magnitudes of these changes vary according to different general circulation models. Given the warming trend, all components of the water balance for permafrost zones will be affected. Precipitation enhancement may yield more rain than snow, and warming will shorten the snow accumulation season. Glaciers at high altitudes may gain mass because of increased snowfall, but ablation may be accelerated at lower elevations. Ground‐ice melt contribution will increase as permafrost thaws. Evaporation increases as the duration of ice cover on lakes is reduced, and over the land, transpiration feedback will modify the rate of evaporative loss. Higher evapo‐transpiration may reduce the extent of the wetlands. In the Arctic, subsurface flow will be more important as the active layer deepens. With increasing ground‐water flow, more rainfall, and less intense snowmelt, the streamflow regimes will be altered. Further research should examine the spatial analogs and apply the present‐day climatic variability to explore climatic change scenarios, and computer models should be used to simulate the possible effects of global warming.