The effects of climate change on discharges and snow cover in Finland

The effects of climate change obtained through model simulations on runoff and snow cover in Finland are presented in this study. The results are based on hydrological model simulations using the information from one climatic general circulation model (GISS) scenario with doubled atmospheric carbon dioxide as input. According to the GISS model scenario, the temperature increase in Finland will be 2-6®C, the precipitation increase 10-30 mm per month and the evaporation increase 5-30 mm per month. The effects of these climatic changes on runoff and snow cover have been evaluated in twelve different watersheds by hydrological watershed models. According to the results the mean discharge (MQ) increases by 20-50%, the mean minimum discharges (MNQ) increase considerably in winter due to a two to three months shorter snow cover period and the mean maximum discharges (MHQ) decrease due to diminished maximum snow water equivalents. In southern Finland persistent winter snow cover will vanish.