Minskning av palsmyrar som resultat av klimatförändringar i norra Sverige mellan 1960–2020

Sammanfattning: The climate is changing at a rapid rate. This causes both an increase in temperature and precipitation in the northern high latitudes. Subarctic peatlands contain 30% of the carbon storage in the northern permafrost zone. Palsa mires are found in the subarctic peatlands in the northern hemisphere limited by the climate zone, which are expected to disappear within the next few decades. Degradation of permafrost can lead to carbon being released into the atmosphere, which contributes to carbon feedback. The Environmental Protection Agency gave the County Administrative Board in Norrbotten an assignment to carry out a total mapping of northern Sweden's palsa mires in 2014. Through aerial image interpretation, the County Administrative Board in Norrbotten made a grid with 100 x 100-meter squares used as an indicator where palsa mires were mapped in Sweden as presence/absence and percentage cover. This was done without any contour digitization. In my study, a total of 60 palsa mires were digitized over two transects in Norrbotten County using ArcGIS Pro and the 100 x 100-meter squares. Spatial and climate data were documented for each of the palsa mires to answer the questions of how the surface of the palsa mires has decreased and how the climate changed between 1960 and 2020. The spatial data consisted of altitude and geographical coordinates. The transects were examined both separately and together to examine differences within and between transects. The climate data consisted of the annual average temperature, seasonal winter temperature, annual average precipitation, seasonal winter precipitation, the length of the vegetation period, and frost days. The results showed that the palsas had a considerable degradation between 1960-2020. There was a difference between the northern and southern transects, for which the palsas had decreased the most in the southern transect. There was an association between reduced palsa surface and higher altitude above sea level. There was also an association between higher N coordinates and greater palsa size, and reduced palsa size with distance from the Scandinavian Mountain range. There has been an increase in both the annual temperatures and the seasonal winter temperatures. More precipitation both annually, and seasonally during the winter. The vegetation period length has increased while frost days have decreased. The palsas size has likely degraded due to the worsening climate conditions that were measured for all the palsas in this study between 1960 and 2020. Reduction of palsa mires leads to large emissions of stored carbon and contributes to positive carbon feedback that is predicted to increase the course of climate change now and in the future.