This week, on a peninsula in south-west France, people were taken off the beaches by boat — not because the holiday had ended, but because the road out was gone. Across France and Spain, more than 250,000 people left their homes in a matter of days. Spain declared a national emergency. Three firefighters were killed.

And here is the part that is hard to square. Europe has never been better at fighting fires than it is right now. Portugal, which keeps the longest fire records in Europe, caught about half its fires while they were still small in 1980; by 2006 it was catching nine out of ten. So how does a continent get better at stopping fires every year and end up with worse fires anyway? The answer starts somewhere that sounds unrelated: over 25 years, Spain has lost almost eleven million sheep — and nobody took over the job those sheep were doing.

On the night of 23 July a fire in the Gironde pushed through the containment line crews had cut around it. By the next afternoon authorities ordered the evacuation of the entire Cap Ferret peninsula, 70 km west of Bordeaux, and sent boats to three piers to take people out by sea. France's interior ministry counted 141,000 people out of their homes in Gironde and neighbouring Landes alone. The region's senior government official called it an XXL wildfire; the president sent in the military as the flames moved toward Bordeaux.

That same day Spain declared a national emergency as fires reached the region around Madrid. Sixty thousand more were moved in central Spain, among them over 430 elderly and disabled residents from five care homes — people who could not leave on their own. Forecast temperatures reached 44 °C. Step back from the week and the season looks worse still: 29 major forest fires against an average of nine, and 114,796 hectares burned — an area larger than Berlin, and more than four times the figure at the same date a year earlier.

What carries a fire across a landscape is the light material — dry grass, fallen leaves, thin twigs, young shrub shoots. Firefighters call it fine fuel: it catches easily and sets the speed of the flame front. What matters just as much is whether it is joined up. Across the ground it gives the flames an unbroken carpet; upwards, it forms a layer of shrubs and low branches half a metre to two metres off the ground — ladder fuels, because they let a fire already burning along the ground climb into the crowns. Once a fire is in the crowns, nothing done on the ground will stop it.

For thousands of years the hills of southern Europe had that fuel stripped out every year by people who were not thinking about fire at all: herds ate the grass and new shoots, dead wood went into stoves, hillsides were terraced and farmed. The result was a patchwork, and a fire moving through a patchwork keeps running out of things to burn. Then the countryside emptied. Spain's sheep population fell 44% in 25 years — almost eleven million animals — and not evenly. Meanwhile Spain has considerably more forest than a generation ago: from a bit more than a quarter of the country in 1990 to well over a third by 2020, driven not by planting but by depopulation and land growing back on its own. That growth is dense, young, continuous scrub on ground nobody tends.

Modern fire services stop almost every fire while it is still small — and every fire caught small is a patch of fuel that did not get eaten. Before anyone was putting them out, small fires crept through the undergrowth every few years and ate exactly the same light material the sheep did. A fire that would once have cleared a few hundred hectares of scrub now gets caught at two hectares, and everything it would have eaten is still standing the following summer.

Crews measure the power of a flame front in kilowatts per metre of burning edge. Around 2,000, ground crews can no longer hold a line without aircraft. Around 4,000, the aircraft themselves begin to lose their effect. Above about 10,000, even the heaviest air tankers cannot hold a line at all. That is a hard ceiling, and no budget raises it. Two things push a fire through it: weather sets how fast it moves — and climate change is pushing that side up hard — while fuel sets how much there is to burn, and we let that side grow for seventy years. They multiply. Which is why, in Portugal in 2024, 35 fires that grew past 500 hectares produced 84% of everything that burned.

Fire scientists have been saying this for decades, so why doesn't the money move? Because there are two different kinds of spending here and they are not treated the same way at all. Putting out a fire is emergency spending: fast, visible, arriving with helicopters on the evening news. Clearing fuel beforehand is an ordinary annual budget line competing with schools and roads — and when it works, nothing happens at all.

Portugal has spent close to three times as much on fighting fires as on preventing them since 2000. And that sets up a loop: the better the fire service gets, the fewer bad years there are, and the less anyone can justify spending on clearing fuel.

Pay the grazer. In Andalusia a scheme running since 2003 pays 220 shepherds to graze 6,000 hectares of firebreaks, paid with cheaper access to public pasture. Catalonia went further: firefighters map where a large fire would actually run, shepherds graze exactly those strips, and the meat and cheese carry a label so shoppers pay a little more — the shepherd earns revenue rather than a subsidy, at about a quarter of the cost of machines. Most of these flocks are goats, which browse upward through precisely the ladder layer. The cost: 6,000 hectares is a network of strips, not a country; grazing has never paid well, so somebody must keep paying permanently; and rebuilding a herding economy takes a decade.

Put fire back. After the 2017 fire at Pedrógão Grande, which killed 64 people, Portugal built a national fire agency reporting to the prime minister and trained crews to light fires deliberately in cool, damp conditions. The cost: it burns about 0.5% of its landscape each year, roughly a tenth of what researchers say is needed; the safe-weather windows are narrow and closing; and one escaped burn can shut a programme down.

Change the duty. Portugal now writes clearance into law — 50 m around a rural house, 100 m around a village, 10 m along a road, backed by fines. The cost: a persistent gap between what should be cleared and what is, and a duty landing on owners who are elderly, absent, or hold tiny plots.

Nothing failed on that peninsula. The system did exactly what it was built to do, and has done it well for decades: stop small fires quickly, and treat the landscape as somewhere you arrive in an emergency rather than somewhere you maintain.

The weather really is getting worse, and that isn't in dispute. But a fire's power comes from two things: how hard the weather pushes it, and how much there is to burn. We cannot turn the heat down this decade. How much there is to burn is the side we can still reach — and it is the one we quietly stopped paying for when the villages emptied. Which makes the question less about why Europe can't fight these fires, and more about why we stopped doing the slow, boring work that kept them fightable at all. It may turn out that one of the most effective tools we have is a herd of goats, and somebody paid to walk behind them.