What has caused ‘unprecedented’ deadly wildfire in southern Spain?

Blaze made worse by heat, strong wind and plentiful dry vegetation amid hollowing out of rural population

Wildfire in southern Spain kills at least 12 amid heatwave

As firefighters struggle to quell the flames ravaging southern Spain and doctors treat the injured, a horrific picture of the fallout is emerging.

At least 12 people died in a fast-spreading inferno that ripped through Almería on Thursday, many trapped in cars as they sought to escape a blaze that scorched 3,800 hectares (9,390 acres). Overwhelmed authorities say eight people have been injured and 23 cannot be accounted for.

Yet the dozen deaths confirmed in Andalucía are likely to represent just a fraction of the fatalities from the fires. Far more deadly than the flames – on a scale that is hard to comprehend even for scientists who study it – is the thick black smoke they spew into the air.

Lung-scarring pollution from wildfires kills a staggering 1.53 million people each year, a study found in 2024, with separate research finding a bad season in a single country, such as Canada in 2023 , can lead to tens of thousands of deaths around the world. Strong winds carry toxic particles across oceans and into homes and lungs.

When record-breaking wildfires torched the Iberian peninsula last year, killing eight people in Spain and six in Portugal, they produced so much toxic smoke that 2,000 people died early, according to a study released as a preprint last month.

That so many people should die is not a given. Fossil fuel pollution and mismanagement of land have laid the groundwork for increasingly fierce blazes across southern Europe, and the coming decades herald a longer fire season that burns stronger and covers a wider area.

Reports suggest the blaze on Thursday may have been sparked by a fallen power line. This summer’s fires are able to spread quickly because a hot summer turned vegetation into a dangerous fuel, preceded by a wet winter and spring that helped plants grow.

“The Los Gallardos wildfire in Almería appears to have faced the worst possible combination: a point of ignition in a vast landscape of extremely dry vegetation, strong winds, and a nearby community that was unprepared,” said Guillermo Rein, a fire scientist at Imperial College London. “These conditions allowed the flames to spread extremely rapidly toward homes, overwhelming the firefighters operating under extraordinarily difficult circumstances. Recent heatwaves had already dried out the landscape, turning the vegetation into highly flammable fuel.”

Western Europe is suffering through its third heatwave in two months and this year’s fires are already among the deadliest in Spanish history. They have burned double the usual area for this time of year, data published on Tuesday by the European Forest Fire Information System shows, with triple the number of fires and above-average emissions. Last year, the high number of simultaneous fires hampered firefighting efforts and allowed small fires to explode into huge infernos.

The steep terrain of the ravine-scarred Sierra de Bédar lends itself to the rapid spread of wildfires, scientists said, and temperatures in the area reached highs of nearly 42C after several days in a row above 35C. “In this area, just a few weeks without rain during the summer are enough for fine fuels to reach very high levels of flammability,” said Gustavo Saiz, a senior scientist at the National Institute for Agricultural and Food Research and Technology.

Alongside the rising heat, the hollowing out of rural Spain has alarmed fire experts as populations age and young people leave farms for jobs in cities. The resultant vegetation overgrowth – alongside the political tendency to suppress fires rather than prevent them – has encouraged large fuel build-ups that make mega-fires more likely.

“The inertia of the two major processes that have brought us to the current situation – land abandonment and climate change – is enormous,” said Juan Picos, a forest fire scientist at the University of Vigo. “Even if we begin implementing ambitious measures immediately, conditions are likely to continue worsening for some time before any significant improvement becomes apparent.”

He compared shock at increasingly “unprecedented” wildfires to someone climbing a mountain and being surprised each day that they had reached a new height. “If they continue climbing, they will almost certainly say exactly the same thing again tomorrow.”