Effects of regional climate change on rural fires in Portugal

Wildfires are a major problem in Portugal. Since 1980 an area equivalent to 3/5 of the forested surface has burned. The aim of the study was to assess the potential impact of regional climate change on wildfires in Portugal using an appropriate Burnt Area Model (BAM). Based on multiple regression analysis, the model was able to estimate the decimal logarithm of the monthly burnt areas in July and August using the Daily Severe Rating as a predictor in the pre-fire season (May and June) and the fire season (July and August). The BAM, which was able to explain 63% of the total observed variance from the 1980−2011 period, was then fed with simulated data by a Global Climate Model (GCM) for the present climate and for two 30 yr periods (2051−2080 and 2071−2100) of future IPCC emission scenario B1. Comparison analysis between the logarithm of burnt area in July and August under present and future climate conditions shows an increase in the mean values of 7 and 11% for the first and second 30 yr periods, respectively, and a decrease of 32% in the SD for the first (2051−2080) period but no distinction between the observed and the simulated values for the last (2071−2100) period. Obtained estimates with the developed approach consistently point towards an increasing risk of fire under future climate conditions, and thus an increasing likelihood of much larger burnt areas.