The regional climate scenarios developed for Sweden, based on global climate scenarios RCP4,5 and RCP8,5, show that Sweden's annual mean temperature will increase by 2 to 7 degrees Celsius by the period 2071-2100 compared to the reference period 1961-1990. The greatest temperature increase is expected to be during the winter, between 2 and 9 degrees by the end of the century. Changes in the summer are estimated to be less than in the winter, between 1 and 6 degrees warmer. These changes have significant regional differences with the biggest effect in the north of Sweden.
An increase in temperature will cause temperature zones to move north. Each degree increase in average temperature corresponds to a north-south distance of about 150 kilometres in Sweden. A warming of 3-4 degrees also results in an upward shift of the tree line by approximately 500 vertical metres.
The length of the growing season (number of days when the average daily temperature for a single period is over 5 degrees) is expected to increase by one to two months throughout Sweden, except in the far south where the increase is estimated to be up to three months. A higher mean temperature of 3 degrees means that Sundsvall in the north of Sweden in the future will have the same average temperature as Stockholm today.
Both average temperature, frequency of number of days with temperatures in certain intervals and the size of the extremes are of major importance for natural systems and society. A rising mean temperature results in gradual changes, even for temperature extremes in terms of both their range and frequency.
Fact: the source for global mean temperature
The increase in the average global temperature by between 0.5 and 5 degrees by 2100, stated at the beginning of this article, is based on conclusions from the report published in 2013 by UN climate panel IPCC (AR5). It is a comparison of the periods 1993-2012 and 2081-2100. The observed global temperature increase during the period 1880-2012 has been approximately 0.85 degrees.