Observed climate variations during the last 100 years in Lapland, northern Finland

Abstract

Many general circulation models (GCMs) predict that high latitude environments will experience substantial warming over the next 100 years, which will be particularly pronounced during the winter months. Precipitation is also expected to increase but there is uncertainty as to the amount and spatial variation. The flora and fauna of the arctic and subarctic regions, together with indigenous people, such as the Saami, are particularly vunerable to rising temperatures and changing precipitation. Mean monthly temperature and precipitation data were examined for the last 100 years for northern Finland. These data were further analysed for the first and second half of the 20th century. There was no discernible warming trend between 1876 and 1993, but a significant annual warming (r=0.344, ρ<0.05) occurred in the period 1901–1945, together with a significant summer warming (r=0.381, ρ<0.05). Warming has occurred consistently in May and June over the last 100 years and there appears to be a current (i.e. post 1990) annual trend, mostly due to winter warming. The greatest temperature anomaly increase for the period 1901–1945 was in the winter months (+0.72°C). The degree of temperature variation in the winter is greater than in the summer and has risen from 3.98°C for December in the period 1901–1945 to 4.37°C in the period 1946–1990. This is attributed to the recent high variability in the North Atlantic Oscillation (NAO) Index. Annual precipitation has increased significantly during the period 1880–1993. The period 1946–1990 was wetter than 1901–1945, with greater variability particularly in the summer months, which contribute most to the annual precipitation in Lapland. Copyright © 2000 Royal Meteorological Society