“The smoke signals from Marseille and Narbonne alert us to the urgency of the ecological transition”

Mediterranean regions have been burning regularly for centuries, due to human activity and the specificity of the climate: these are regions where the hottest season corresponds to the driest period. Plants have perfectly adapted to this particularity, whether in terms of leaf morphology or metabolic activity. They have established fairly advanced resistance processes, which are reflected in particular by the emission of volatile organic compounds. These emissions are more abundant when temperatures and drought increase.

If these volatile organic compounds are the trademark of typically Mediterranean plants (the famous aromatic plants), they contribute, at the slightest spark, in the heart of summer, to transforming the garrigues and maquis into "bombs" ready to explode. The omnipresence and virulence of fires are part of the very nature of Mediterranean ecosystems. The accidental outbreaks of human origin and the rapidity of the evolution of fires are also described by Jean Giono, in 1929, in his novel Colline .

We might therefore be tempted to say that there is nothing new under the sun – and yet, this is not true. The situation has changed over the last few decades. The socio-ecological consequences of fires have in fact worsened considerably, with agricultural abandonment [the abandonment of cultivated land] and the dynamics of peri-urban expansion: they have led to the spatial connection of human habitations with natural spaces, without us being aware of the incompatibility of practices with the presence of adjoining spontaneous vegetation.

In the context of climate change, this observation is worrying: the "Mediterranean" version of warming is materializing through increasingly long periods of drought (especially in summer, but sometimes also in winter) and, above all, heatwaves which dry out vegetation, and even the soil, particularly quickly.

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