Key facts
- France experienced its most destructive wildfires on record this summer, forcing mass evacuations.
- The fires were fueled by a dense monoculture of maritime pines planted after an 1857 decree.
- Climate change has intensified heatwaves and drought, creating ideal conditions for large-scale fires.
- The ignition source is under investigation, with a faulty utility machine a primary focus.
- Scientists suspect the fires generated a rare firestorm thundercloud, dispersing pollutants.
The recent devastating wildfires in France, particularly the one near Bordeaux in late July, have set new records for land burned and evacuations, prompting scientists to suspect the country's first firestorm thundercloud. The conditions leading to these infernos are rooted in historical land management and exacerbated by climate change.
In the 18th century, the south-western French wetlands were swampy, but an 1857 decree by Napoleon III mandated draining these areas and populating them with maritime pines, creating Europe's largest human-made forest. This forest, now a significant economic driver employing 30,000 people, is also a major fire risk due to the resinous, fast-burning nature of the pines and their flammable needles and cones, which spread flames rapidly.
This monoculture lacks the moisture retention and shady canopies of diverse broad-leafed species, allowing fires to spread with extreme fury. A similar blaze in 1949 burned 50,000 hectares and killed 82 people, making it Europe's deadliest wildfire. Despite improved firefighting capacity, the risk has escalated due to global warming, which has warmed Europe by 2.4C and increased the frequency of hot, dry extremes.
A wet winter followed by relentless heatwaves this year created an abundance of dry fuel. Record high temperatures and low soil moisture in July set the stage for the Gironde fire. The blaze near Saumos, west of Bordeaux, is under investigation, with a faulty machine used by Enedis utility workers being a leading line of inquiry. Arson is also a significant factor, with hundreds arrested on suspicion of starting fires.
The fire spread rapidly, engulfing hundreds of hectares within hours and reaching the outskirts of La Porge and the Cap Ferret peninsula. Criticism has emerged regarding the firefighting response, with local forestry workers suggesting a controlled burn was rejected and residents claiming resources were diverted. The French government also faced criticism for having only seven of its 12 water-bombing planes operational during the peak of the fire.
Authorities evacuated nearly 220,000 people in France and over 300,000 across France and Spain, an unprecedented peacetime displacement in Europe. While no direct fatalities resulted from the Gironde fire, four firefighters died tackling separate blazes. Scientists believe the extreme energy released by the fires may have generated a pyrocumulonimbus cloud, capable of creating its own weather and spreading embers, while also dispersing dangerous pollutants.