The extremely hot, dry and windy conditions, which fueled one of the Iberian Peninsula's most destructive wildfire seasons in recorded history, were 40 times more likely due to climate change, according to a study released Thursday.
The analysis by World Weather Attribution, or WWA, said the weather conditions were about 30% more intense compared to the preindustrial era, when heavy reliance on fossil fuels began.
Summer wildfires Hundreds of wildfires in the Iberian Peninsula broke out in July and August. They spread rapidly thanks to temperatures that pushed above 40 degrees Celsius (104 Fahrenheit) and strong winds.
The fires in Spain and Portugal killed eight people, forced more than 35,000 evacuations and scorched more than 640,000 hectares (1.58 million acres) or roughly two-thirds of Europe’s total burned area this year.
Most blazes are now under control, officials say, as temperatures have dropped considerably.
“Hotter, drier and more flammable conditions are becoming more severe with climate change, and are giving rise to fires of unprecedented intensity,” said Clair Barnes, a researcher at the Center for Environmental Policy at Imperial College, London.
Europe has been warming twice as fast as the global average since the 1980s, according to the European Union’s Copernicus Climate Change Service.
WWA, a group of researchers that examines whether and to what extent extreme weather events are linked to climate change, focused on the conditions that allowed the Iberian wildfires to spread that fast, including during Spain's hottest ten-day period on record in August, according to the country's weather agency AEMET.
Without climate change, similar ten-day spells of hot, dry and windy conditions would be rare, expected once every 500 years, they found.
“This quick study is one more line of evidence showing how human-caused climate change increases the frequency and intensity of extreme heat and combined hot and dry fire weather conditions,” said Valérie Masson-Delmotte, a climate scientist at the French Alternative Energies and Atomic Energy Commission, who was not involved in the study.
WWA's analysis wasn't a full attribution study. Those seek to determine the influence of climate change, driven primarily by the burning of fossil fuels, on a specific extreme weather event. This time, the researchers looked at weather observations without using climate models. But the results were consistent with existing research on wildfires in the region, the researchers said, and another study WWA recently published on this year's fires in Türkiye, Greece and Cyprus, which found that climate change made fire-prone weather conditions there 10 times more likely.
“While fires are a characteristic of the Mediterranean climate, human-caused climate change increases the recurrence and severity of conditions favorable for intense fires, making fire control efforts much more challenging,” Masson-Delmotte said.
The researchers mentioned other factors that have contributed to the severity of the wildfires, including large population shifts that have taken place over decades in Spain and Portugal from the countryside to cities. The study said this has resulted in large areas of neglected overgrown farms and forests, which further fuel the fires.
Removing vegetation using machinery, encouraging grazing by sheep, horses and goats and using other methods, such as controlled burns, would reduce the risk during wildfire seasons, researchers said.
“From a human perspective, most of these rural areas have suffered massive abandonment since the 1970s, which has allowed fine fuels to accumulate to dangerous levels, a problem worsened by inadequate forestry management,” said Ricardo Trigo, a professor at the University of Lisbon's geophysics, geographical engineering and energy department.
On Monday, Spanish Prime Minister Pedro Sánchez proposed a 10-point plan to better prepare the country for natural disasters made worse by climate change. It included coordinating with neighboring Portugal and France.
