The Heinrich Boll Foundation and the Pulitzer Center provided grant support for this story.

When the speeding BMW emerged out of the smoke of burning eucalyptus trees, heading straight for her firetruck, Filipa Rodrigues had no time to react. “I had time only to think, ‘We’re going to crash,’” she says, massaging the burn marks on her arms, and then the car plowed into them, and the five volunteer firefighters stumbled out from their ruined truck into an inferno.

It was high summer in 2017, and they had just crossed into the outer bands of the worst firestorm to ever hit Portugal, a presage for a new age of mega-fire that would soon stalk across landscapes from Spain to Australia. Rodrigues, then 24, stepped outside and her safety goggles immediately melted to her face; as she ripped them off, skin came with them. She blinked through the smoke at eucalyptus trees flying by, burning, in the winds of the biggest flames she had ever seen.

Rodrigues was not a professional—like three generations of her male relatives, she was a member of the bombeiros, the volunteer firefighting corps that since the 1950s has served as first line of fire defense for the towns of the rugged, hardscrabble, limestone hills of the Portuguese interior. Every summer all types—doctors, teachers, mail carriers, college students—take their vacations at the local fire station, where they wait round the clock for word of fire.

It was far from Rodrigues’s first wildfire. But she had never seen any like it: As the flames bore down on them faster than they could run, with their truck on fire and their radios melted, she immediately understood that she was going to die. The bombeiros tried to pull the BMW’s passengers out of the car—“We were screaming, screaming, but they didn’t respond”—but the heat forced them back, and they watched the flame take the BMW and its occupants. The twisting column of flame coming for her seemed unstoppable.

“It seemed,” she says, “like the fire would take the entire world.”

View Images Columns of smoke rise from a forest wildfire in Góis, Portugal, on June 20, 2017. Photograph by Patricia de Melo Moreira, AFP/Getty Images

In a sense she was right. The new kind of mega-fire that broke out in the highlands of central Portugal on June 17, 2017, was the perfect firestorm brewed when an increasingly unstable atmosphere meets a landscape poised to burn. It’s also a warning of what the future holds for Mediterranean-style ecosystems from Turkey and Spain to Greece and California as climate change drives increasingly longer dry periods.

“Portugal is the canary in the mine,” says Tiago Oliveira. Today he is director of AGIF, the Portuguese national fire control agency, but back in 2017 he was a corporate fire scientist, managing fire control for Navigator, the $1.5-billion Portuguese pulp company that grows eucalyptus in enormous plantation tracts for pulp and paper.

After nearly being killed in a plantation fire in 1998—two comrades had broken and run before the fire, which caught them—Oliveira had turned himself to the question of why Portugal’s fires seemed to be getting worse. That question would drive him on to a doctorate and a series of papers on fire science with researchers at universities like MIT.

His conclusion: Portugal, like the wider Mediterranean, was suffering from the confluence of two long-term trends: a sweeping abandonment of a rural landscape that had become economically irrelevant, coupled with a widespread governmental unwillingness to live with fire.

“And if your aim is to exclude fire from this ecosystem,” he says, “you are doomed to fail.”

When humans rise, forests fall

It is a truism of the relationship between civilization and forests that where one rises, the other will fall back. From the Bronze Age up until the 1950s, Oliveira notes, civilization and industry rested on the resources provided by forests.

“Peasants used pine straw to mix with manure for compost; firewood for the hearth; forest pastures for livestock; resins and wax for home industry,” he says.

The Phoenecian traders and artisans who sailed up the Ebro River at the end of the Bronze Age found stands of primeval hardwoods perfect for making the charcoal needed to forge high-quality swords, as well as the axes that fed the forges. Their Carthaginian descendants lopped off Roman spear-points with razor sharp falcata, swords made with charcoal from upland oaks. The Romans who laboriously defeated them cleared the remaining Iberian forests for new industry: vineyards, goats, and sheep—wine, dairy, wool—and for the scaffolding and smelters of their gigantic silver mines worked by the enslaved.

“By (Roman) antiquity,” says Pedro Bingre do Amaral, a professor of land use at the University of Coimbra, “the Portuguese landscape was almost treeless,” cut back by a series of advancing civilizations.

By the 1300s, the uplands had become so deforested that the kings began to plant pine trees to control erosion. When the Portuguese burst outward in the early modern area, every single wooden ship sailing back and forth between Lisbon and the Estado da India or Captaincy of Bahia, carrying the wealth, slaves, and soldiers of the Portuguese Empire, required 2,000 oaks and an equivalent number of pines.

Then, starting in the early 20th century with a spike that began in the 1950s, the pattern flipped. At the turn of the century Portugal had 2 percent tree cover; by the late 20th century it had shot up to nearly a third. The reason, Oliveira says, was this: In the 1950s, synthetic materials made from petroleum replaced plant and animal fiber, and chemical solvents and fertilizers made from petroleum and inorganic chemicals replaced forest products like pitch, peat, or pine needles, Factory farming replaced meat from hunting or domestic animals— cows, sheep, pigs goats—pastured in the forest. As rural people withdrew from the land that once filled their basic needs, the trees returned, and with them came fire.

For bombeira Filipa Rodrigues, that pattern, which geographers call the “forest transition”—the return of forests to abandoned cropland – could be laid out in one statistic: When her father volunteered at the station in the 1980s, “we could count on 20 professionals.” Now they had seven. For more than a century, the highlands had been emptying out. Sons, sisters, cousins made their way down the mountain to Lisbon and onward to Canada, South Africa, or Brazil.

“We have a problem in the highlands, and that problem is people,” says volunteer firefighter Hugo Carvalho, who worked as a mail carrier in the nearby town of Proença-a-Nova, watching as the elderly died or moved and the lights went dark.

View Images Residents watch plumes of smoke and flames rising from forest fires on the outskirts of the village of Cardigos in July. Photograph by Horacio Villalobos, Corbis/Getty Images

Trees came up in abandoned yards and fields, crowding against the tall grass and fire-loving shrubs that dried into fuel in the summer heat. They came down the new greenways of vacant houses, pointed like daggers into the hearts of towns, their seeds spreading on the fierce winds that blew in from the Atlantic.

Yet unlike the primeval forests that Phoenecian sailors found 3,000 years ago, these new forests were feral, the half-wild, escaped offspring of the tracts of Atlantic pine and imported Australian acacia and eucalyptus.

Which is to say: three fast-growing tree species, packed with essential oils, each of which had evolved to spread with wildfire.

As increasingly serious fires burned through larger and larger swaths of the interior, the Portuguese government, Oliveira says, “got stuck in a firefighting trap.” Faced with a public outcry to do something, the Portuguese legislature passed new laws, bought new hardware, and moved quickly to “kill” the small blazes that could become large ones.

Meanwhile the core problems—the abandoned countryside, the seasonal, volunteer firefighters, and the land base filling up with fire-loving trees—continued to fester, and by the summer of 2017, after more than a decade of aggressive termination of small fires by the bombeiros, the interior was stocked with fuel, waiting for a spark.

View Images Wildfires broke out in th​e northern and central parts o​f Portugal in 2010, following abnormal​ly hot weather. Photograph by Angelo Lucas, Camera Press/Redu​x

A perfect firestorm

On June 17, 2017, it came. A series of fires ignited in the valleys around the town of Pedrógão Grande, fueled by winds that blew down off a strange and unseasonal thunderstorm like a bellows, fanning the flames into three separate, enormous flame fronts.

Source: MODIS Collection 6 NRT Hotspot / Active Fire Detections via Google Earth Engine

That June afternoon, Rodrigues and the rest of her crew of bombeiros had just killed a small blaze with their high-pressure hoses. As they headed up the mountain toward Pedrógão Grande, Rodrigues realized that night was falling early: There was so much soot in the air that the sky had gone dark.

They did not know it yet, but they were driving into the teeth of something few in Europe had ever seen before. One of the few who had was fire scientist Marc Castellnou, in Catalunya, an autonomous region in neighboring Spain. As the chief fire scientist for Catalunya’s force of 5,000 professional firefighters, Castellnou had, like Portuguese fire chief Oliveira, become disturbed by the appearance of fires of unprecedented fury and destructive power.

A fire’s power, he explains as we drive through the sun-baked pines near his hometown of Tivissa, toward where a fire ripped through the previous month, comes down to fuel and its ability to supply itself with oxygen, both of which had been steadily growing along with the increasingly unruly forests. In teaching his firefighters, Castellnou had used the metaphor of “five generations” of wildland fire from the first, when trees began to cover whole Iberian landscapes in the early 1900s, leading to fires of unprecedented size; to the fourth, when the inrush of trees and outgrowth of suburbs conspired to place ever more people in the “wildland urban interface,” complicating any firefighting plans that had previously relied on allowing land to be triaged; to the fifth, in which simultaneous big fires strained the resources of firefighting crews.

By the fifth generation, Castellnou says, “we began to lose” to fires that outflanked and outmatched them. Then in January 2017, the European Commission sent him to Chile, where Castellnou saw something categorically worse than he had ever seen before: the overture to the new age of megafire. A forest fire is the product of a powerful, nonlinear chemical reaction, the release of energy trapped in the carbon bonds of trees. Its ability to spread is directly, even exponentially, proportional to the fuel available to it, and to how energized and reactive the atmosphere is.

Sufficiently powerful fires have always been able to create their own weather. Iberian firefighters I spoke to describe facing fire tornadoes, or the dreaded mushroom of the pyrocumulus, in which a plume of hot air rises into the atmosphere and collapses back down, feeding the fire that started it.

What came in Chile, Castellnou says, was far worse: a pyrocumulonimbus cloud, a fire system that reached the border of space.

“We have never seen something of this size, never in Chile's history,” President Michele Bachelet said , visiting the ashes of a territory about the size of Delaware that within two days had been reduced to a moonscape—killing 11 people and creating thousands of refugees. In the town of Santa Olga alone, a thousand houses burned.

The new instability in the atmosphere and the unprecedented fuel stocks of the unmanaged forests had come together, Castellnou says. Later, fire scientists like Craig Clements, of San Jose State University, would hypothesize that the plume had become so big that it reached the troposphere; on the ground, theory gave way to practicality.

“We could not fight them,” Castellnou said. “You just had to get away, and try to change the conditions on the ground to starve the fire.”

On his return to Europe, he told the Commission that they would likely be seeing these pyrocumulonimbus fires—which he called “sixth-generation megafires”—in Europe within five years. “Today’s conditions in the Mediterranean,” he told them, “are tomorrow’s in Central Europe.”

View Images A landscape devastated by wildfire in Vila de Rei, Portugal. The burned trees reveal terracing, which shows that the forest wasn't virgin; it regrew over abandoned fields that at one point had been improved. Photograph by Horacio Villalobos, Corbis/Getty Images

But he had underestimated how quickly things were changing. Barely five months later, he watched on a live feed from the Pedrógão Grande fire station as the flames rose above the forest that Filipa Rodrigues’s crew was driving into.

It was, he would say later, a repeat of Chile, a replay of the “nightmare scenario” that unfolds when cold Atlantic winds meet a hot Mediterranean summer. In the Portuguese highlands, the wildfires burned through the dense, abandoned forests below an atmosphere vibrating with sustained heat, as a column of unstable, superheated air streamed upward as through a chimney above the highlands. Hundreds of panicked weekenders and tourists, unaccustomed to the regular fires of the backcountry, fled down narrow, overgrown roads, heading for the safety of the coast.

Many drove directly into a death trap. Usually night offers a respite from fire. In the Mediterranean, Proença-a-Nova fire chief Tiago Marques told me, firefighters besiege a fire by day and kill it by night, when falling temperatures and rising humidity undermine its power.

Not now. This fire, as fire scientist Craig Clements would later conclude, had grown too hot. Instead of slowing the fire, the oncoming dew boiled off the flame front like water off the rocks of a sauna, sending a pulse of superheated steam almost to the borders of space. As it pillowed up against the frigid edge of the earth’s atmosphere, the steam condensed and fell as hail, pushing a mass of frigid air down on top of the wildfire.

In any combustion reaction, more compression means more heat and power: The downrushing front made the difference between wildfire and blast furnace. On the video feed from Pedrógão Grande, Castellnou watched the collapsing downburst depress the fire column horizontally toward the trees, now clogged with cars. At around nightfall they caught, and within minutes 8 square kilometers of woodland, packed with fleeing vacationers, burst into flame.

Lost in the dense smoke, cars swerved into trees, guardrails, and each other, creating deadly pileups and road blockages as the fire came on faster than anyone thought possible.

It was that inferno that the terrified couple in the BMW had been fleeing—and that Rodrigues and her companions were now trapped in. They staggered toward the BMW, just a few meters away, but were forced back by a heat that scorched their skin through their fireproof clothes. They watched as the flames swallowed the car.

The firefighters fell back to a crossroads, skin bubbling and lungs blistered, their truck and radios destroyed, the fire approaching at a fast jog. One would die from lungs blistered by superheated air; the others would have as well -- had fate not intervened in the form of a pickup truck that had been forced to turn back in the face of the flames.

They were exceedingly lucky. The fate of those trapped inside the flames would spread trauma across the highlands and the wider Portuguese consciousness, particularly the stories and forensic evidence from the deadly roadblocks on National Highway 236, quickly dubbed The Highway of Death.

“They died if they ran, and they died if they stayed in their cars,” says Nadia Araceli Piazza, a lawyer who lost her son and ex-husband to the fires.

Their cause of death, like 65 others trapped and killed that June day—the bulk of them on roads like Highway 236—was “carbonization.” Many were found, she notes, wrapped around their loved ones, their muscles tightened in their last moments by the heat of the flame.

These dynamics, Castellnou and Oliveira say, have been seen across the world in the past three years, as sixth-generation fires have shown up in Mediterranean climates everywhere—meaning ecosystems from the Americas to Australia—wherever cold ocean winds blow across sun-kissed, dry mountains bursting with fire-loving plants.

In 2018, 83 died in Greek fires whipped up by a similar long downburst during a summer when forest fires burned, for the first time in history, in every European country. The following year, a pyrocumulonimbus like Portugal’s October 2017 fires collapsed in a long waterfall over flames spreading from an electrical leak in Southern California—where unchecked suburban development has crowded into the traditional fire lanes of the chaparral—killing 90 and nearly wiping the town of Paradise, California off the map.

How to live with fire

Castellnou and Tiago Oliveira, the Portuguese national fire chief, are part of a new wave of wildland firefighters who believe that the solution is a new way of living with fire.

View Images Private firefighters clear bushes close to a eucalyptus forest during an August drill at Constância in Abrantes, central Portugal. Photograph by Patricia de Melo Moreira, AFP/ Getty Images

Both fire scientists believe that the best strategy lies in a full-time approach to fire defense—unlike the bombeiros’ seasonal approach—with firefighters building and maintaining fire lines throughout the year so they will be prepared to battle fires when they break out, as well as keeping development out of established fire lanes.

But the fire problem will not be solved, Oliveira says, without the evolution of a new kind of rural landscape, where people value the forest once again and defend the land from fire, because they use it again, be it for pasturing sheep and goats, or beekeeping, tourism, or small-scale biomass energy generation.

This is not as sexy as buying new helicopters, he admits ruefully, and lacks the rural romance of the bombeiros. “No one was ever called a hero,” Oliveira says ruefully, “for averting a crisis before it happened.”

Still, he believes the model of so-called polycentric governance, poli-sci speak for giving local people the authority and resources to solve their fire problems locally, combined with a revitalized rural economy, are the only long-term way for the Portuguese interior, or other Mediterranean ecosystems like California, Chile, Greece, or Spain, to manage their overwhelming fire risk—a risk that is moving north into the unprepared lands of the rest of Europe.

This is happening in a few settlements. In Proença-a-Nova, tech company Novatech has moved in from Lisbon, and dozens of young workers are now getting married and moving back onto country houses where they mow grass and tend orchards. In the nearby village of Ferraria de São João, hotelier Pedro Pedrosa led his neighbors in uprooting the eucalyptus that crowded their village, building terraces that they planted with native cork oaks, whose thick cambium serves as a fire retardant—to the north of town, Pedrosa says, a 200-year-old stand of oaks had broken the wave of fire before it could consume the town.

“We need to step away from a top-down approach,” Portuguese fire chief Oliveira says. For too long, the people of the countryside had relied on centralized state authority, and on the beloved volunteer firefighters, to stop the wildfire problem. If it can use the fire danger to inspire a recolonization of its rural hinterlands, Oliveira says, “Portugal can be the case study for the rest of Europe.”

But he knows a bomb is ticking in the background. The changes in Lisbon have not yet penetrated to most of the backcountry, where burnt-out pines still stick from denuded hills like worn-out toothbrushes, stubby, oil-packed eucalyptus already springing up beneath them. One surreal impact of the generations of neglect of the highlands by the central government is that Lisbon doesn’t know who owns the bulk of the land in the interior, which makes establishing land policy virtually impossible, though a federal survey is ongoing.

And the rural population, says Filipa Rodrigues, the former bombeira, is weaker and more demoralized than it has ever been. Two years after the 2017 fires, the experience of the firestorm has left her mind and extremities scarred.

“We had never failed before,” she says in her home in Castanheira do Pera. “Now I see fire,” she says, gesturing at her fireplace, “and I start to tremble. We live with the consequences of what happened—the people we lost—every day.”

It becomes easy, she says, to abandon land that others are already abandoning. She does not want to leave, but with a limited local economy, a young daughter, and a great risk of fire, she is not sure how she can stay. Most of her friends live in Lisbon, their family lands growing over behind them. Every day she watches the eucalyptus grow, unchecked and illegal, bare meters from the house where they sleep.