The Susceptibility of the Circumpolar North to Zombie Wildfire : An Exploratory Case Study of Sweden

Sammanfattning: Climate change is warming the North and exposing its immense carbon stores not only to wildfire disturbances, but overwintering, or zombie, fire. These remnants of summer fires can spend months smouldering under the surface, hidden under the protection of layers of snow, burning through immense amounts of carbon, which is then released into the atmosphere, further exacerbating climate change. In order to prevent these potential megafires, areas that are prone to their occurrence need to be identified so that detection and management protocols can be put into place. Using a GIS approach, this paper attempts to identify any areas in the northern circumpolar country of Sweden that are currently susceptible to zombie fire and any that might be susceptible in 2050 using a RCP8.5 scenario projection. Based on spatial and climatic variables, the results found 88 km2 of land that is currently susceptible, 20.19 km2 of which is most prone due to mild winter and spring conditions. In the 2050 projection, most regions were found to have a decrease in susceptibility due to warmer winters reducing snow coverage. However, three counties in the north were found to have an increased susceptibility due to the earlier arrival of spring. Climate projections still contain uncertainties and how the annual precipitation of Sweden will be affected by climate change varies greatly between models, which naturally effects the likelihood of future wildfires, and ensuing zombie fires. There is a need for more research surrounding zombie fires, particularly with regards to snow depth and coverage and how this affects the mechanisms of smouldering combustion and smouldering to flaming transition. This paper is an example of how regions can be assessed for hazardous events if they have some spatial and temporal predictability.