Dränerade våtmarker och deras växthusgasutsläpp - En kartläggning av organogena jordar i Kristianstad kommun

Sammanfattning: Emissions from drained organic soils is a big contributor to global warming and corresponds to 5% of global and 25% of Sweden’s greenhouse gas (GHG) emissions. This study uses a GIS-analysis to map the organic soils in Kristianstad municipality in Sweden and what land use occurs on these soils. The purpose of the study is to provide the municipality with information when investigating the possibility of rewetting these soils. Emission factors based on land use are used to estimate the emissions from the organic soils within the municipality. Also, a map showing the biggest areas of organic soils and information about the land-use, history, soil type and soil humidity of these areas, is produced. The results shows that 6,7% of the land in Kristianstad municipality is covered with organic soil, which is less than the Swedish average of 15,2%. The most common land use is crop land followed by forests, and about a third of the organic soils is located on land registered as wetland or forest on wetland. The estimated GHG-emissions from the drained organic soils are 106 633 tones CO2-equivalents, which corresponds to 29% of the emissions reported within the municipality (which does not currently include carbon emissions from drained organic soils, if included, it would make up 23% of total emissions). The percentage of emissions from drained organic soils is larger in Kristianstad than in Sweden at large, even though the percentage of land coverage of these soils is smaller. This is due to the large area of crop land in the region, which is the land use with the highest emission factor. Calculations in the study shows that more than 70% of the emissions theoretically can be avoided if all the organic soils are again covered with water. A discussion then follows about the possibility and priority of rewetting different areas.