Just as an enormous wildfire tears through the suburbs of Athens, scientists in Europe are racing to understand why "extreme" fires like this are becoming more common.
The conditions for some of these fierce blazes have become between three and 20 times more likely, according to the first research of its kind.
The new annual review of what is causing extreme fires, and whether we can predict them, comes off the back of a staggeringly destructive wildfire season from March 2023 to February 2024.
Record-breaking flames scorched Canada and turned skies far away in New York orange and grey. The largest recorded fires in the European Union killed 19 people in Greece, and blazes in western Amazonia brought filthy air to local towns.
Today's major study, published in the peer-reviewed journal Earth System Science Data, finds carbon emissions from wildfires in 2023-2024 were 16% above average, spewing out 8.2 billion tonnes of carbon dioxide into the atmosphere.
And, had it not been a quiet fire season in the African savannahs, the global emission from wildfires would have been the greatest of any fire season on record since 2003, they said.
What is an 'extreme' wildfire?
There is no single definition of what constitutes an extreme fire, because it is relative to the location, said one of the authors Dr Douglas Kelley, from the UK Centre for Ecology and Hydrology (UKCEH).
It could be measured by things like burned area, intensity, or how unusual they are, depending on the region.
But they used three mega blazes in Canada, Greece, and western Amazonia last year as a benchmark.
The current flames in Greece would count as an extreme fire because of its proximity to and potential damage to people, said fellow author Dr Joe McNorton from the European Centre for Medium-Range Weather Forecasts (ECMWF).
At 200 square kilometres, this year's fires in Greece are still much smaller than the 900 square kilometres burned last fire season.
That's because the current flames are at the "wildland-urban interface", which brings with it "potential loss of life, destruction, economic devastation" said Dr McNorton.
Climate change raised the chances of unprecedented fires last year
Human-driven climate change made the tinderbox conditions of 2023-24 up to three times more likely in Greece, similar in Canada and 20 times more likely in western Amazonia, today's paper found.
They then looked at "how likely we are to get them in the future", said Dr Kelley.
If the world warms by up to 2C by 2100, sticking to Paris Agreement goals, they project such a fire in Canada will be two to three times more likely, but no change in Greece and western Amazonia.
But if temperatures warm by more like 3C, extreme fires like last year will be up to 11 times more likely in Canada, three in Greece and 1.3 in western Amazonia.
Other research shows the number of intense fires has been rising.
How does climate change impact extreme fires?
Climate change is "clearly increasing" fire conditions, said Dr Matthew Jones from the University of East Anglia.
Warmer temperatures dry out forests, which make a fire "more likely to spread", said Dr Kelley. It can also cause more vegetation to grow, which provides more "fuel" for the fire.
Human factors also influence fires, like starting them themselves, or breaking up the landscape, or how well they fight them.
How do fires impact climate change?
Although the number of extreme fires is on the up, the total amount of land being burned has been decreasing.
That is a bit of a "red herring" said Dr Jones, because it's due to a fall in the less harmful savannah fires, as things like agriculture break up the grassland, often bringing better protection or irrigation.
But what scientists are really concerned about is the rise in wildfires in forests.
Forest wildfires release more carbon emissions, pose a higher risk to people, take longer to recover, and mean the loss of huge carbon storage.
That's why global fire emissions have barely budged even though land area burned has fallen - and there's a fear global emissions from fires could soon increase.
More extreme fires in Canada and western Amazonia are "quite worrying... in ecosystems which hold a lot of carbon and in some cases, don't experience much fire today, so they haven't really adapted to it," said Dr Kelley.
What can be done?
Dr Clair Barnes from Imperial College London, who was not involved with the study, said she hopes the report will both "guide preparations for wildfires, and help the world understand the simple fact that fires will keep getting worse until fossil fuels are replaced with renewable energy sources".
Scientists agree that emissions need to fall in order to avoid future risk - but that will take a long time to have an impact.
In the meantime, the authors said, leaders should consider protecting forest boundaries, reducing the amount of natural fuel fire, imposing fire bans on high-risk days, and investing more in early warning prediction systems.
Victoria Seabrook