Evaluating present and future fire risk due to climate change in the Mediterranean: a case study for Greece

The current climate change trend in the Mediterranean causes longer summer droughts and intensification of these droughts even out of season. Extreme weather events, such as periods of high temperatures, prolonged dry spells and very strong winds, as well as sudden storms with heavy rainfall are becoming more frequent. As a result, the frequency of large-scale forest fires is on the rise and the same holds true about soil erosion which is aggravated when such fires are followed by heavy rains a few days later. When a period of drought and high temperatures is followed by a day of peak temperatures, low relative humidity and very strong winds, fire danger reaches extreme levels and multiple fires can easily get out of control creating havoc. In order to investigate the future changes in fire risk in relation to the meteorological conditions in the Mediterranean, the Canadian Fire Weather Index (FWI) is applied. FWI is a daily meteorologically-based index designed in Canada and used worldwide to estimate fire danger in a generalized fuel type. The FWI system provides numerical ratings of relative fire potential based on weather observations. FWI components depend solely on daily noon measurements of dry-bulb temperature, air relative humidity, 10 m open wind speed and 24 h accumulated precipitation. The scope of this study is to investigate the impacts of climate change on fire risk for the Mediterranean, for two future time periods, 2021-2050 and 2071-2100, compared to the control run period 1961-1990. Subsequently, several regional climate models from EU-Project ENSEMBLES (www.ensembles-eu.org) are used to provide input for the FWI system. Moreover, an evaluation of the index is performed using current 7-year fire and meteorological data for Greece, in order to examine whether FWI values can adequately reflect fire risk as judged by actual fire occurrence and area burnt, with particular emphasis on the most vulnerable region of Southern Greece. FWI is confirmed to be skillful in predicting fire occurrence and thresholds of elevated (FWI>15) and extreme (FWI>45) fire risk are established. The results indicate that the future projections suggest a general increase in fire risk over the domain of interest for the near-future period 2021-2050, while a very strong impact is projected for the end of the century (2071-2100). ACKNOWLEDGEMENT: This work is prepared in the framework of EU project CLIM-RUN whose support is gratefully acknowledged.