The projected 21st century forest-fire risk in Finland under different greenhouse gas scenarios
Ilari Lehtonen, Kimmo Ruosteenoja, Ari Venäläinen, Hilppa Gregow
Abstract
We evaluated forest fire potential at four locations in Finland in the current climate and in projected future climates under the B1, A1B and A2 greenhouse-gas (GHG) emission scenarios. In evaluating the forest fire danger potential, the Canadian fire weather index (FWI) system was used. Using the results of the earlier experimental ignition studies, we further estimated the number of fire danger days in different forest stands typical to the northern boreal zone. By the end of the current century, the annual median number of days with elevated forest fire risk is projected to increase by 10%–40%, depending on the GHG scenario. In different forest stands, approximately 5–10 additional fire risk days were found annually based on the A1B and A2 scenarios. Substantially smaller changes are projected under the low-emission B1 scenario. However, there is great inter-annual variability in the forest fire potential which, in the nearest future, largely overwhelms the projected change.