Climate scenarios for FINADAPT studies of climate change adaptation. FINADAPT Working Paper 15

Abstract

Climate change scenarios for Finland were constructed for three tridecadal periods, 1991-2020, 2021-2050 and 2070-2099, separately for the SRES A2 and B1 forcing scenarios. Depending on the quantity, projections are based on output from 3-6 global climate models. Under the A2 scenario, by 2070-2099 mean temperatures are projected to increase almost 4°C in summer and more than 6°C in winter. In winter, minimum temperatures tend to increase more than the maximum temperatures, and diurnal temperature range is reduced by about 2°C. Precipitation increases more than 20% in winter. Summers appear to be slightly sunnier than at present, and soil moisture content is reduced up to by 30%. Hot summer days will be about four times more common than today. Frost-free period in summer will lengthen by more than 2 months. In wind velocities, no statistically significant changes were found. For the end of the century, the B1 scenario produces smaller responses than the A2 scenario. During the two earlier time spans, the two scenarios do not diverge markedly, and changes are statistically less significant than at the end of the century. There are several factors of uncertainty in the present projections. For example, current climate models describe the behaviour of the nature only incompletely, and the number of models included in this account was small. Moreover, the future temperature, precipitation etc. conditions are affected, in addition to anthropogenic forcing, by unforced natural variability occurring in the climate system.