Journal cover Journal topic
Natural Hazards and Earth System Sciences An interactive open-access journal of the European Geosciences Union
Nat. Hazards Earth Syst. Sci., 16, 239-253, 2016
https://doi.org/10.5194/nhess-16-239-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
21 Jan 2016
Risk of large-scale fires in boreal forests of Finland under changing climate
I. Lehtonen1, A. Venäläinen1, M. Kämäräinen1, H. Peltola2, and H. Gregow1 1Finnish Meteorological Institute, Helsinki, Finland
2University of Eastern Finland, School of Forest Sciences, Joensuu, Finland
Abstract. The target of this work was to assess the impact of projected climate change on forest-fire activity in Finland with special emphasis on large-scale fires. In addition, we were particularly interested to examine the inter-model variability of the projected change of fire danger. For this purpose, we utilized fire statistics covering the period 1996–2014 and consisting of almost 20 000 forest fires, as well as daily meteorological data from five global climate models under representative concentration pathway RCP4.5 and RCP8.5 scenarios. The model data were statistically downscaled onto a high-resolution grid using the quantile-mapping method before performing the analysis. In examining the relationship between weather and fire danger, we applied the Canadian fire weather index (FWI) system. Our results suggest that the number of large forest fires may double or even triple during the present century. This would increase the risk that some of the fires could develop into real conflagrations which have become almost extinct in Finland due to active and efficient fire suppression. However, the results reveal substantial inter-model variability in the rate of the projected increase of forest-fire danger, emphasizing the large uncertainty related to the climate change signal in fire activity. We moreover showed that the majority of large fires in Finland occur within a relatively short period in May and June due to human activities and that FWI correlates poorer with the fire activity during this time of year than later in summer when lightning is a more important cause of fires.

Citation: Lehtonen, I., Venäläinen, A., Kämäräinen, M., Peltola, H., and Gregow, H.: Risk of large-scale fires in boreal forests of Finland under changing climate, Nat. Hazards Earth Syst. Sci., 16, 239-253, https://doi.org/10.5194/nhess-16-239-2016, 2016.
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Short summary
The number of large forest fires in Finland will most likely increase during the twenty-first century in response to projected climate change. This would increase the risk that some of the fires could develop into real conflagrations which have become almost extinct in Finland due to effective fire suppression. However, our results show considerable inter-model variability, demonstrating the large uncertainty related to the rate of the projected change in forest-fire danger.
The number of large forest fires in Finland will most likely increase during the twenty-first...
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