To the many problems caused by wildfires, add reduced solar generation and more use of fossil fuels as a result. A study of the 2023 Canadian wildfires has concluded that drifting smoke caused a 3 per cent drop in solar power generation in both Europe and North America, costing nearly $2 billion.

鈥淚t鈥檚 clear that we are facing a situation where this is going to keep happening,鈥� says Iulian-Alin Ro葯u at the Technical University of Crete in Greece. 鈥淚t seems like every year from now on, we are going to have some relatively significant Canadian wildfire events.鈥�

Smoke from large wildfires in Canada can spread across much of the northern hemisphere, reducing how much sunshine reaches the ground. Last year, Ro葯u reported that so much smoke was released during the massive 2023 wildfires in Canada that it reduced summer temperatures across the hemisphere by nearly 1掳C 鈥� which still wasn鈥檛 enough to stop 2023 being the hottest year on record, now surpassed by 2024.

He recently discussed his findings with fire expert at the University of East Anglia in the UK. 鈥淲e were looking at pollution maps and Matthew, out of nowhere, says, well, hang on a second, I wonder what this does to solar power production,鈥� says Ro葯u.

So Ro葯u, Jones and their colleagues got data on solar generation in North America and Europe and plugged it into the climate model Ro葯u used for his 2025 study. Their study takes into account the fact that the cooling effect of smoke slightly compensates for less sunshine by increasing the efficiency of solar panels 鈥� by 20 per cent in Europe, for instance.

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Based on electricity prices at the time, the team calculates that North America 鈥� mainly the US 鈥� lost $711 million, while Europe lost almost $1.17 billion, with Germany being hit hardest. The reason why Europe lost more is largely that electricity prices are higher there, says Ro葯u, plus most solar generation in the US is in southern and western states that were less affected by smoke.

The impact of the smoke was greater than the researchers expected, he says. 鈥淎 whole bunch of solar power was not being produced, and that led to increased CO2 emissions, because obviously the rest of the energy industry had to compensate.鈥�

鈥淭here needs to be more understanding of the fact that fire can affect pretty much everything: pollution, health, weather and even solar power,鈥� he adds.

With smoke from Canada reaching Europe again this year, the same thing is happening again. 鈥淚 have seen some relatively worrying data for this year as well,鈥� says Ro葯u. But with the season still ongoing, he says it鈥檚 too early to compare with 2023.

A pyrocumulonimbus cloud, a looming thunderstorm generated by an intensely hot wildfire, has been observed with radar in France for the first time. These deadly 鈥渇ire clouds鈥� of rising hot air, smoke and moisture, which accelerate blazes with strong winds and soaring embers, are expected to become more common in Europe as wildfires there get bigger. 聽

鈥淵ou have this tilted column that is sucking air and then propagating embers in front, and it also creates lightning. That鈥檚 another way of lighting up fuels in front of the fire, so these cells are unstoppable,鈥� says at the University of Corsica, France. 鈥淵ou cannot stop a thunderstorm, and neither can you stop a firestorm, a strong pyrocumulonimbus.鈥�

Alongside huge blazes in Spain, France has been suffering a wildfire in the Gironde region, which President Emmanuel Macron has called the country鈥檚 most severe crisis since the second world war. The fire has burned more than 420 square kilometres since last week, coming within 15 kilometres of the city of Bordeaux and forcing around 220,000 people to evacuate. It generated a pyrocumulonimbus cloud on 24 July and another on 25 July, according to regional officials. Embers and lightning ignited new fires around the original inferno.

鈥淲e faced another firestorm, the same incredible, unprecedented, unknown phenomenon as the one we saw on Friday, when we realised we were entering a new dimension,鈥� Gironde prefect Sophie Brocas told journalists.

It is a miracle this pyrocumulonimbus-fuelled fire hasn鈥檛 claimed any casualties, Filippi says.

Sometimes the 鈥渇ire-breathing dragon of clouds鈥�, pyrocumulonimbus are typically generated by massive wildfires in the forests of North America, Siberia and Australia. They鈥檝e spurred on infamous fires like the that killed 173 people in Australia in 2009 and the conflagration that in 2016. Canada鈥檚 record-breaking wildfires in 2023 142 of these storms.

In Europe, however, there have been only a handful of confirmed pyrocumulonimbus in Spain and Portugal, including one during Portugal鈥檚 devastating Pedr贸g茫o Grande fire in 2017, which destroyed hundreds of homes and killed 66 people. But that appears to be changing.

鈥淵ou have to have two things happening at the same time: an extreme heat source and an unstable atmosphere that interacts with the fire,鈥� says at the European Centre for Medium-Range Weather Forecasts. 鈥淚f鈥� the heat from the fire increases, like it鈥檚 projected to increase from our studies, then yes, you should see more of these events.鈥�

This firestorm begins to take shape when temperatures as high as 800掳C send a plume of smoke into the sky. As the hot air rises and cools, water vapour condenses onto the ash to form pyrocumulus clouds, like the fluffy white clouds you might see on a summer day, only brown or grey. 聽

If the plume is hot enough and the atmosphere is unstable enough, the cloud can keep rising to reach the upper troposphere at 10,000 metres, the cruising altitude of a passenger plane. It sometimes reaches the stratosphere, as much smoke as a moderate volcano. It becomes a pyrocumulonimbus when the static electricity from colliding ice particles sparks thunder and lightning.

Although rain from the cloud often evaporates in the hot air, this kind of thunderstorm nonetheless creates its own weather system. The cloud鈥檚 updraft pulls in air, fanning the flames with winds reaching 160 kilometres per hour and accelerating the fire鈥檚 spread by up to five times, according to Filippi.

Meanwhile, strong downdrafts create erratic gusts that carry embers off to start new fires. Dozens of lightning strikes can blazes as far as 100 kilometres ahead of the main fire. It can also create fire tornadoes of twisting flames. As the winds, embers and lightning strengthen and expand the wildfire, it releases more heat and smoke, a feedback loop that can amplify the rising cloud for many hours.

Both wind shear higher in the atmosphere and erratic gusts at the ground can take the fire in unpredictable directions, making it nearly impossible to contain its acceleration or plan targeted evacuations.

鈥淭he fire front is constantly shifting. We cannot fight it directly. It鈥檚 a David-versus-Goliath scenario,鈥� Eric Brocardi of the National Firefighters Federation of France local media about the Gironde fire on 2 August. 聽

Wildfire plumes have expanded in height since 2003 in the western US, creating more pyrocumulonimbus clouds, an increase that鈥檚 projected to continue.

Pyrocumulonimbus will have more chances to occur in Europe as well, as the fastest-warming continent experiences more extreme heat, such as the record-breaking heatwave in June, and wildfires. could also contribute, such as when a wet spring last year boosted vegetation growth on the Iberian peninsula, only for record summer heat to dry it out. This led to Europe鈥檚 worst-ever wildfires, including a in Spain.

鈥淲e need to adapt, so get prepared,鈥� Filippi says. 鈥淏urn-proof and reduce the amount of fuel around your house.鈥�

Climate and health activist has been immortalised in a sculpture, The Solomon Siren 鈥� recently installed on her now-flooded former home: Kale Island in the Solomon Islands.

Rising tides completely flooded the 50,000-square-metre Pacific island in 2016. The sculpture sits in the intertidal zone, where patches of rubble and sand rise above the ocean surface from time to time.

Sculptor Jason deCaires Taylor made the sculpture as part of his Sirens series of installations around the world highlighting warming seas, sewage pollution and the presence of microplastics.

When flooding made life untenable, Bartlett and her family had to evacuate to one of the main islands. 鈥淏ack then, [the island] was land 鈥� green, vibrant, full of life,鈥� says Bartlett in a film accompanying the sculpture鈥檚 installation. 鈥淜ale became one of the first documented islands in the Solomons lost to sea level rise.鈥�

The sculpture consists of a marine-grade stainless steel tree on which a life-sized figure of Bartlett leans. The artwork also uses biochar and pH-neutral cement. Hauntingly, as the tide rises and falls, it is intermittently hidden as waves roll over.

Incorporated into the sculpture are inscriptions recording past milestones of Kale鈥檚 submergence along with predictions for a sea level rise of up to 20 centimetres by 2046. But as Taylor says, the sculpture isn鈥檛 intended to work as a scientific measuring instrument, but as a 鈥渟ymbolic representation鈥� of a changing relationship between land and sea.

鈥淲hat happened is a warning not only for us, but for the world,鈥� says Bartlett.