The world is losing forests to fire at an unsustainable rate, experts have warned.
Wildfires have always been part of nature’s cycle, but in recent decades their scale, frequency and intensity in carbon-rich forests have surged.
Research from the World Resources Institute (WRI) shows that fires now destroy more than twice as much tree cover as they did two decades ago.
In 2024 alone, 135,000km² of forest burned – the most extreme wildfire year on record.
Yet fires in other landscapes have not risen in the same way, according to research from the University of Tasmania. While the total area burned globally has fallen for decades as farms have expanded across Africa and slowed the spread of blazes – forests have become a new hotspot.
The rise in forest fires is unmistakable. Four of the five worst years on record have occurred since 2020.
Research from the WRI shows that 2024 was the first time that major fires raged across tropical, hot and humid forests such as the Amazon, and boreal forests, such as those spanning Canada’s vast coniferous regions.
Some of the world’s worst-affected areas
Brazil, Bolivia, Russia, Australia and Canada have all endured some of their worst fire seasons in recent years, as heatwaves stoked by fossil fuel pollution drive the risk of extreme blazes higher.
The maps, using data from the University of Maryland, show some of the hardest-hit forests.
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Russia has suffered three of its worst fire seasons on record since 2020, with 2021 the most severe. About 45,000 km2 of forest was burned – mainly across Siberia and Russia’s far east.
The fires extended so far north that they reached permafrost regions within the Arctic Circle, and in 2021, satellite sensors recorded the northernmost wildfire ever recorded. As more permafrost thaws – drying soil, warming air, and reducing humidity – scientists expect an “abrupt increase” in wildfires.
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In 2023, 78,000 km2 of forest burned in Canada – another record-breaking fire season. The choking smoke killed Carter Vigh, a nine-year-old with asthma playing at summer camp in British Columbia, along with 82,000 others. The fine particles of toxic pollutants spread so far that Europe shouldered one-quarter of the death toll. Firefighting resources were pushed to their limit across several Canadian provinces, and the fires forced mass evacuations.
The fires reached previously unburnt areas in the boreal north, and weather stations recorded temperatures up to 10C higher than average.
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Wildfires were especially extreme across swathes of South America in 2024 – with the Amazon once again being heavily impacted. 23,000 km2 of forest burned in Brazil alone, with the majority of that in the Amazon – its second worst year on record. The Brazilian states of Pará, Rondônia and Mato Grosso suffered some of the fiercest blazes. Flames also penetrated into Indigenous territories and protected areas.
Extreme heat and drought, attributed to climate change and the El Niño effect, led to more extreme fire conditions. This was then made worse by illegal deforestation, land grabbing and agricultural clearing.
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Australia’s 2019 to 2020 fire season was so bad it became known as the “black summer”. Millions of hectares of land burned nationwide. While the worst effects of the 2019-20 bushfires on property were in the eastern states, forestry suffered more in western Australia.
Several contributing factors have been identified as to why these forests were affected so severely: ongoing drought, high winds, heatwaves and changing land use practices. More than 3,000 homes were destroyed and over 30 people died during this fire season. An estimated three billion animals also perished as crucial ecosystems such as the Stirling Range national park burned.
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How climate change is driving this change
Experts warn that climate change is making wildfires bigger, longer and more destructive. Hotter, drier conditions are extending fire seasons and fuelling more extreme blazes.
2023 and 2024 had the most forest area burned by wildfires on record. They were also the two hottest years on record.
Northern latitudes are heating faster than the global average, driving a surge in boreal forest fires.
James MacCarthy, wildfire research manager with the Global Forest Watch initiative at the WRI, said: “Because of where they grow and how climate patterns are changing, boreal and temperate conifer forests are warming and drying faster than most other forests.
“Fire is a natural part of these ecosystems, but the traits that once helped them survive infrequent burns – like thick bark and seeds that are released in response to fire – are now being overwhelmed as fires grow larger, more frequent and more severe.”
“Fires are increasingly burning in places that were historically too wet to ignite and rarely caught fire, like peat-rich forests.”
A vicious cycle
What makes burning forests even more concerning is the fact that, normally, they are carbon sinks.
By absorbing CO2 and storing it in trees, plants and soil, forests normally regulate the climate by reducing greenhouse gases and slowing the pace of global warming.
But when they burn down, the carbon that they have stored is released into the atmosphere.
In 2023 and 2024, forests only absorbed a quarter of the CO2 they do in a typical year.
MacCarthy warned: “When these forests and peatlands burn, they release carbon that has been locked away in trees and soil for hundreds of years, accelerating climate change and setting the stage for more fire. Smoke from these fires can travel thousands of miles, polluting the air for millions of people, while nearby communities face evacuations, health risks and mounting costs.”
Calum Cunningham, research fellow at the University of Tasmania fire centre, said: “Massive forest fire seasons threaten to reshape the atmosphere by releasing huge amounts of CO2, which could create a feedback loop – more warming, worse fire weather, more fire. That’s the ultimate fear.”
Curbing the damage
Reducing human-caused carbon emissions and addressing climate change is the crucial step in tackling fires.
But experts say local action is also essential. Halting deforestation, restoring degraded land and managing fire risk in vulnerable regions can all help curb the damage.
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Bolivia’s 2024 fires were its worst on record. More than 10,000 km² of forest burned – double the previous high. Experts warn that worsening drought and the rapid spread of agriculture are fuelling a surge in fire activity across the country.
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But some forests in Bolivia escaped the worst of the flames.
Charagua Iyambae, a newly established Indigenous Territory in southern Bolivia, had invested in early warning systems and land-use policies that helped prevent the spread of forest fires.
A crucial protected area within the territory – called Ñembi Guasu – largely avoided the worst of the fires due to a combination of Indigenous-led governance and practical fire-management. It is a 12,000 km2 area and home to jaguars, giant armadillos and tapirs.
This involved local Guaraní park rangers using satellite monitoring to report risks quickly to authorities, enabling quick action before small ignitions spread. Pre-positioned people and gear were quick to stamp out or block fires before they became bigger problems.
All of this meant that, while the map above shows how swathes of Bolivian forests burned last year, Charagua Iyambae was left relatively untouched – even areas that burned before.
But authorities cannot be complacent. In early September this year, the territory declared a disaster as flames entered the protected area. Rainfall eventually helped extinguish them, but the episode showed there is no such thing as fire immunity.
Some fire-affected forests can regrow if given the chance: in Australia, for example, many ecosystems are adapted to recover after low-intensity burns, though recovery depends on the species lost and the extent to which the land is left ecologically degraded.
Experts warn that these trends will continue as climate change gets worse. The ongoing rise in global temperatures is expected to create even more conducive conditions for wildfires, leading to longer and more intense fire seasons.
Boreal and temperate conifer forests, already experiencing rapid warming, are especially vulnerable. Without significant action, the vicious cycle of warming leading to more fires, less carbon absorption and further warming is set to accelerate.
The WRI’s MacCarthy said that a combination of local and global solutions will be needed to solve the crisis.
“To reduce the growing risk of forest fires, we need to address the underlying drivers. Cutting greenhouse gas emissions can limit the hot, dry conditions that fuel fires, while ending deforestation can slow climate change and prevent forest fires linked to land clearing.”
