The climate changes generated by anthropogenic impact are increasing the intensity and frequency of meteorological events that were once sporadic and remote, but, as Amitav Ghosh reminds us in his essay The Great Derangement, "nothing is remote in the age of global warming, there is no place where the ordinary expectations of bourgeois life are not called into question".

Among these phenomena are wildfires, whose frequency and intensity will increase in the coming decades.

Wildfires are increasing with climate change

This is revealed by a study conducted by researchers at the Istituto di geoscienze e georisorse del Consiglio nazionale delle ricerche (Igg-Cnr) in collaboration with the universities of Barcelona, Lisbon and California Irvine. The research, published in the journal Scientific reports, demonstrated the link between drought and the increase in areas affected by wildfires, highlighting how wildfires will grow in the coming years, particularly in areas to the north of Mediterranean Europe.

The link between wildfires and drought

To assess the risk of wildfires in the coming decades, the scientists developed mathematical models capable of predicting the hazard and extent of fires. "By analysing the data we seek to determine empirical but robust relationships between variations in drought conditions and burned areas," explained Antonello Provenzale, director of Igg-Cnr. "Although most fires are ignited by human activity, deliberate or otherwise, we have established that climatic conditions influence the spread and therefore the extent of a fire."

The study

To develop the mathematical models required for the study, the researchers took into consideration two variables: burned area (Ba) and drought quantified using the Spei (Standardized precipitation evapotranspiration index), an index that measures the difference between precipitation and evapotranspiration — that is, the amount of water that passes from the soil into the air as vapour. "By studying the annual variations in Spei and Ba, we analyse anomalies — in other words, how much, in a given year, the values deviate from their mean. In general, the data show that burned area anomalies follow Spei anomalies in an almost linear fashion. If the Spei anomaly in a given year doubles compared with the previous year, the burned area will also tend to be double that of the previous year," stated the director of Igg-Cnr.

An increasingly arid Mediterranean

The Mediterranean area is undergoing a gradual and unstoppable aridification, with a reduction in rainfall and a consequent increase in drought. The projections are far from encouraging: "in the coming decades we can expect a significant increase in burned area in Mediterranean Europe," confirmed Marco Turco of the University of Barcelona. The study, in addition to analysing the link between wildfires and drought, determined for the first time whether summer wildfires are more strongly influenced by drought conditions during the same summer or during previous years. "Thanks to the analysis of data from the European forest fire information system (Effis) and national archives, we have demonstrated for the first time that the increase in fire extent is driven more by the dry conditions of that same summer."

Italy is among the most at-risk areas

According to the researchers, the areas most threatened by the increase in wildfires are the more northerly zones of Mediterranean Europe, such as northern Italy, France and Catalonia, "whose ecosystems have adapted less over past centuries to the progressive drought that the area is experiencing," concluded Antonello Provenzale. The study represents a valuable tool for developing strategies to prevent and counter the hazards posed by wildfires.