New analyses show how the climate can change in Swedish counties

New reports from SMHI provide geographically detailed information about climate trends in Sweden, depending on future levels of greenhouse gases. The climate analyses can be used for community planning and highlights increasing risks as the climate changes.

The new reports are produced for all Swedish counties. Analyses are based on data from regional climate models, statistically downscaled to provide geographically detailed information about climate trends in Sweden. Two different scenarios are used, one based on a strong climate policy to reduce emissions, and the other on today's climate policy with continued accelerating emissions.

Climate analyses can be used for different types of planning and climate change adaptation, in sectors such as construction, nature conservation, drinking water strategy, emergency management, tourism, agriculture and forestry - but also for the general study of climate change.

- The new results confirm previous findings, we get higher temperatures and more precipitation. The analyses clearly show that the climate is affected by the emissions, and the greatest changes occur from the middle of the century, says Elin Sjökvist, project leader at SMHI.

Greatest temperature increase and more precipitation in the north

The average temperature in Sweden increases 2-6 degrees by the next century, depending on the amount of emissions. The warming is greatest in northern Sweden. Average precipitation will increase by up to 50 %, mostly in northern Sweden. Heavy rainfalls will increase by approximately 20 % across the country. Flows in Swedish waterways are expected to increase in winter and decrease in summer. The highest flows, causing risk of flooding, will generally decrease in northern Sweden and increase in southern Sweden. Number of days with snow cover is expected to decrease by 40-80 days.

The county analyses are based on climate observations and calculations according to two development paths, limited emissions of greenhouse gases (RCP4.5) and continued high emissions (RCP8.5). The future scenarios are compared with the so-called normal period 1961-1990. These dimensions and concepts are used as the international standard in this field.

Number of days with snow cover

Tre kartor som visar förändring av snötäcket
The number of days with snow cover is decreasing in Sweden to the end of the century. In the scenario with limited emissions of greenhouse gases (RCP4.5, map in the middle) a reduction of about 40 days is estimated. The high emissions scenario (RCP8.5, map to the right) shows a reduction of approximately 80 days.
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Change in extreme water flows

Två kartor visar scenarier för extrema vattenflöden
Extreme water flows will increase in southern Sweden, and decrease in northern parts of the country by the end of the century. Predicted change in 100-year floods is shown in the maps: scenario with limited emissions of greenhouse gases (RCP4.5, map to the left), scenario with high emissions (RCP8.5, map to the right).
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Content of the reports

All county analyses contain detailed map data with climate scenarios for different time periods, and the reports include variables; temperature, rainfall, runoff and soil moisture. There is also information about snow and more detailed information about runoff for the northern counties. For the southern counties scenarios regarding water availability, cooling and heating requirements are presented and also more information on rainfall.

SMHI has developed the analyses within the framework of a government remit and in consultation with the county administrative boards. The material includes 21 county reports, a technical report which mainly describes the methodology, and a database.