Modelling the effects of climate change on water resources in central Sweden

This article describes investigations into the effects of climate change on flow regimes of twenty-five catchments (from 6 to 1293 km(2)) in central Sweden. Hydrological responses of fifteen hypothetical climate change scenarios (e.g. combinations of DeltaT = +1, +2 and +4 degreesC and DeltaP = 0, +/- 10%, +/- 20%) were simulated by a conceptual monthly water balance model. The results suggest that all the hypothetical climate change scenarios would cause major decreases in winter snow accumulation. Significant increase of winter flow and decrease of spring and summer runoff were resulted from most scenarios. Attendant changes in actual evapotranspiration were also examined for all climate change scenarios. Despite the changes in seasonal distribution of evapotranspiration, the change in annual total evapotranspiration was relatively small with the maximum change of 23% compared with the 76% for mean annual snow water equivalent changes and 52% for mean annual runoff changes. Such hydrologic results would have significant implications on future water resources design and management.