Scientists have long known that fires release substantial amounts of greenhouse gases and pollutants into the atmosphere.
However, estimating the total climate impact of fires is challenging.
Now, new satellite data has shed fresh light on the complex interplay between the climate and fires in different landscapes around the world.
It suggests that global emissions from fires are much higher than previously assumed.
In this article, we unpack the latest update to the Global Fire Emissions Database (GFED) – a resource that combines satellite information on fire activity and vegetation to estimate how fires impact the land and atmosphere.
The latest update to the database – explored in new research published in journal Scientific Data – includes data up to and including the year 2024.
It reveals that, once the data from smaller fires is included, fire emissions sit at roughly 3.4bn tonnes of carbon (GtC) annually – significantly higher than previous estimates.
It also shows that carbon emissions from fires have remained stable over the past two to three decades, as rising emissions from forest fires have been offset by a decline in grassland fire emissions.
The database update also illustrates how the amount of area burned around the world each year is falling as expanding agriculture has created a fragmented landscape and new restrictions on crop residue burning have come into force.
Landscape fires
Fire events vary widely in cause, size and intensity. They take place across the globe in many types of landscapes – deserts and ice sheets are the only biomes that are immune to fire.
When vegetation burns, it releases greenhouse gas emissions, which contribute to global warming. It also releases pollutants that cause local air pollution and, on a global scale, have a cooling effect on the climate.
Forest fires often generate considerable media attention, especially when they threaten places where people live.
However, the forest fires that make the news represent just a small fraction of all fires globally.
More than 95% of the world’s burned area occurs in landscapes with few trees, such as savannahs and grasslands.
Fires have helped maintain tropical savannah ecosystems for millions of years. Savannahs have the perfect conditions for fire: a wet season which allows grasses and other “fuels” to grow, followed by an extended dry season where these fuels become flammable.
Historically, these fires were ignited by lightning. Today, they are mostly caused – intentionally or accidentally – by humans.
And yet, despite their prevalence, these fires receive relatively little media attention. This is not surprising, as they have been part of the landscape for so long and rarely threaten humans, except for their impact on air quality.
Fires also occur in croplands. For example, farmers may use fire to clear agricultural residues after harvest, or during deforestation to clear land for cultivation.
The term “landscape fires” is increasingly used to describe all fires that burn on land – both planned and unplanned.
(The term “wildfire”, on the other hand, covers a subset of landscape fires which are unplanned and typically burn in underdeveloped and underinhabited land.)
Calculating the carbon emissions of landscape fires is important to better understand their impact on local air quality and the global climate.
New data
In principle, calculating carbon emissions from fires is straightforward. The amount of vegetation consumed by fire – or “fuel consumption” – in one representative “unit” of burned area has to be multiplied by the total area burned.
Fuel consumption can be determined through field measurements and satellite analysis.
For example, the burned area of a relatively small fire can be measured by walking around the perimeter with a GPS device. Fuel consumption, meanwhile, can be derived by measuring the difference in amount of vegetation before and after a fire, something that is usually only feasible with planned fires.
In practice, however, fires are unpredictable and highly variable, making accurate measurement difficult.
To track where and when fires occur, researchers rely on satellite observations.
For two decades, NASA’s MODIS satellite sensors have provided a continuous, global record of fire activity. To avoid too many false alarms, the algorithms these satellites use are built in a way so fires are flagged only when they burn an entire 500-metre grid cell.
However, this approach misses many smaller fires – resulting in conservative estimates of total burned area.
The latest update to the GFED includes, for the first time, finer-resolution satellite data, including from the European Space Agency’s “sentinel missions”.
This data shows that fires too small to be picked up by a satellite with a 500-metre spatial resolution are extremely common. So common, in fact, that they nearly double previous estimates of global burned area.
The data shows that, on average, 800 hectares of land – an area roughly the size of Australia – has burned annually over the past two decades.
The map below shows the frequency of fires around the world. Regions shaded in dark red burn, on average, 50-100% each year. In other words, fires occur annually or biannually. Regions in dark blue, on the other hand, are those where fires occur, but are very infrequent. Most regions fall in between these extremes.
The map shows that the areas most prone to fire are largely found in the world’s savannah and agricultural regions.
Falling burned area
Over recent decades, the total burned area globally each year has been declining.
This is largely due to land-use change in regions which used to have frequent fires.
For example, savannah is being converted to croplands in Africa. This transforms a frequently burning land-use type to one that does not burn – and creates a more fragmented landscape with new firebreaks which limit the spread of fire.
The decline in burned area is also due to the introduction of more stringent air quality regulations limiting crop residue burning in much of the world, including the European Union.
The amount of “fuel” – or biomass – in a unit area of land varies greatly. Arid grasslands are biomass-poor and, therefore, produce less carbon emissions when burned, whereas fuel consumption in tropical forests with peat soils is extremely high.
Maps of carbon emissions from fires closely resemble maps of burned area. However, they typically highlight biomass-rich areas, such as dense forests.
This is illustrated in the map below, which shows how fires in regions coloured dark red on the map produce, on average, 1,000-5,000 grams of carbon per square metre. In these places, much more carbon is lost during fires than gained through photosynthesis.
Meanwhile, much of the world’s savannah regions are coloured in yellow and orange on the map, indicating that fires here produce between 100-500 grams of carbon per square metre.
Rising forest fire carbon emissions
The boost in fire emissions captured by the latest version of the GFED is most pronounced in open landscapes, including savannahs, grasslands and shrublands.
Forest fire emissions, on the other hand, have barely changed in the updated version of the database. This is because most forest fires are relatively large and were already well captured by the coarse resolution satellite data used previously.
However, the trend in forest fire emissions is sloping upwards over the study period.
Overall, current estimates – which take into account the new data from smaller fires – suggest that, over 2002-22, global fire emissions averaged 3.4GtC per year.
This is roughly 65% higher than estimates set out in the previous update to the GFED, which was published in 2017.
For comparison, today’s fossil fuel emissions are around 10GtC per year.
Comparisons between fire and fossil fuel carbon emissions are somewhat flawed, as much of the carbon released by fires is eventually reabsorbed when vegetation regrows.
However, this is not the case for fires linked to deforestation or the burning of tropical peatlands, where regrowth is either much slower – or non-existent, if forests are converted to agriculture. These fires account for roughly 0.4GtC each year – just less than 12% of total fire emissions – and contribute directly to the long-term rise in atmospheric carbon dioxide (CO2).
The traditional view of forest fires as “carbon-neutral” is increasingly uncertain as the climate changes due to human activity. Longer fire seasons, drier vegetation and more lightning-induced ignitions are increasing fire frequency in many forested regions.
This is most apparent in the rapidly-warming boreal forests of the far-northern latitudes. The year 2023 saw the highest emissions ever recorded by satellites in boreal forests, breaking a record set just two years before.
Moreover, the fires in boreal forests are becoming more intense – meaning they burn hotter and consume a larger fraction of vegetation. This, in turn, jeopardises the recovery of forests.
In cold areas, fires also cause permafrost to break down faster. This happens because fires remove an organic soil layer that has an insulating effect which prevents permafrost thaw.
The map below shows the dominant fire type in different regions of the world, including boreal forest fires (dark green), cropland fires (red), open savannah (darker yellow) and woody savannah (brown).
Changing ‘pyrogeography’
Thanks to more precise satellite data we now know that fire emissions are higher than we thought previously, with the new version of GFED having 65% higher overall fire emissions than its predecessor.
However, all evidence suggests that emissions from fires have been stable over the past two to three decades. This is because an increase in forest fire emissions is being offset by a decline in grassland fire emissions.
The world’s changing “pyrogeography” is illustrated in the bar chart below, which breaks down annual fire emissions across different types of biome.
It shows how low-intensity grassland fires with modest fuel consumption – represented in yellow and brown – have declined over time, while high-intensity forest fires – illustrated in green colours – are becoming more prominent, albeit with substantial variability in emissions year-on-year.
The post Guest post: Why carbon emissions from fires are significantly higher than thought appeared first on Carbon Brief.
Guest post: Why carbon emissions from fires are significantly higher than thought
SYDNEY, Thursday 30 October 2026 — In response to reports that the Albanese government is set to introduce draft legislation this year that would seek to ban data centres in Australia’s suburbs, Joe Rafalowicz, Head of Climate and Energy at Greenpeace Australia Pacific, said:
“These reports are a testament to the growing community opposition to these completely inappropriate AI factories that have sprung up across our suburbs, and Big Tech corporations should take heed — the data centre build-out must not happen without the endorsement of the Australian people.
“But the government can’t simply ship this problem out to regional Australia without addressing the fundamental issues with this extractive new industry.
“We’re already seeing a trend of AI data centre proposals moving to the regions, in areas that are more water-scarce, more environmentally sensitive, and next to sources of fracked and coal seam gas to support their massive BYO gas-fired power plans — a pattern we’ve seen play out in the United States.
“From the Beetaloo Basin in the NT to the Western Downs in Qld, we’re seeing a wave of AI data centre proposals that would see new gas fast-tracked to support their massive energy demand, and threaten to completely derail Australia’s energy transition.
“Just as suburban Australians are asking, “what for?”, regional communities like Berry Springs and Dalby do not want dirty data centres setting up shop with absolutely no benefit to their communities. Greenpeace is calling for a moratorium on AI data centre developments until strict and enforceable safeguards are in place to protect our climate and our communities.”
-ENDS-
Media contact
Kate O’Callaghan on +61 406 231 892 or kate.ocallaghan@greenpeace.org
AI data centre ban in suburbs would not address fundamental issues: Greenpeace
In the thick of the COP29 climate summit in Azerbaijan in 2024, the UN climate talks were rattled by what can only be described as a major PR disaster. The BBC, Reuters and The Guardian all carried headlines, attributed to leading climate policy experts, that the COPs were “no longer fit for purpose”.
The articles outlined a series of reforms called for in an open letter signed by 22 eminent scientists and politicians, including a former UN secretary-general and previous UN climate chief, with a further 150 lending their support. The headlines shook confidence in the COP process, just as governments were wrestling over a new climate finance goal.
The Club of Rome – which handled the media relations for the letter – hurried to say that its “constructive, supportive ideas” had been “misinterpreted”. Negotiators kept calm(ish) and carried on, in the end landing the finance goal after some high-stakes drama on the final day.
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Early speakers’ list suggests few powerful leaders will attend COP31
Just 77 heads of state or government are scheduled to address the COP31 climate summit in Antalya, a third less than the COP28 peak -
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The African Group wants dedicated space on tripling adaptation finance, the Green Climate Fund and trade, setting up a possible clash
To my surprise, when I went back this week to read the letter again, I could not find the offending line about the COPs not being fit for purpose. The Club of Rome has yet to respond to my query about its disappearance.
Whatever happened to the wording, that sentiment has been widely shared. COPs have ballooned in size while the importance of their outcomes seems to have diminished since the 2015 Paris Agreement (with the exception of the 2023 COP in Dubai where countries agreed to transition away from fossil fuels in energy systems).
The same on the surface
Two years on from those painful headlines in Baku, has anything changed for the better? You might be forgiven for thinking not. Official decisions are still made by consensus rather than the majority voting some have called for to stop blockers.
Tens of thousands of officials, activists and business execs still scurry around the halls to an ever-growing list of side events, roundtables and dialogues, while deals still come down to rows, all-nighters and jargon-filled texts adopted to rounds of applause.
But it would not be true to say that COPs have completely failed to respond to the very real need to translate the words of the Paris Agreement into action in the outside world.
Global warming is projected to be around 1.3C lower this century than it would have been if the world had not committed to tackle the climate crisis under that accord. Developing countries have a valued space at COPs in which their voices have equal weight in decision-making, unlike in many other international fora. And most importantly, perhaps, there has been a subtle shift, tipping the balance away from negotiating towards doing.
Brazil branded last year’s summit in Belém as the “COP of Implementation”, corralling the sprawling Action Agenda into six axes. This was a bid to impose some structure on the mushrooming efforts between governments, UN agencies, cities, businesses and civil society to set targets and spur faster results on their pet issues, from methane emissions to health and adaptation in conflict zones. COP30 alone saw the launch of 120 “plans to accelerate solutions”.
COP30 roadmaps off the cuff
Meanwhile, as the formal negotiations drew to a close, it was clear that consensus decision-making was evolving into something a little more improvised.
With only around half of all countries on board with the idea of a roadmap to transition away from fossil fuels, COP30 President André Corrêa do Lago announced his team would put one together over the coming year, along with another on how to meet a global goal to halt deforestation by 2030. Those roadmaps will be launched next week, presented and discussed at COP31, though it’s still unclear whether or how they’ll be incorporated into the formal negotiating agenda.
Some leading policy-makers don’t think that matters too much. Speaking to journalists before the Antalya summit, COP30 CEO Ana Toni and Dutch climate minister Stientje van Veldhoven said “coalitions of the willing” can move ahead without needing consensus from the COPs. This, they said, was evident this year at the first global conference on TAFF, co-chaired by van Veldhoven and attended by 60 countries.
“Consensus or no-consensus in the general COP doesn’t make a difference for the choices I have to make in my country to get my country to phase out fossil fuels,” said the Dutch minister. The Netherlands recently became one of the first to publish a national TAFF plan.
COP31 banks on flagship voluntary initiatives
This thinking has permeated the management and expected outcomes of this year’s COP too. Earlier this year, Türkiye, supported by international energy agencies, floated the idea of a voluntary goal to boost electrification to 35% of the world’s final energy consumption by 2035 – and this is now being touted as one of the main results to be expected from Antalya.
Türkiye is also championing a pledge on AI and climate, while co-host Australia is pushing to ease access to climate finance for least developed countries and small island states.
COP31 presidency announces AI pledge as UN climate chief says Big Tech ‘on thin ice’
None of these needs consensus. But with a political cover decision already in the works, as trailed by the COP presidents, they – and perhaps the fossil fuel roadmap – may find a home in the official text if language acceptable to most can be found, giving them them additional weight.
UNFCCC reform process in the shadows
Formal reform is underway too, if quietly. UN climate chief Simon Stiell is leading a review informed by ongoing consultations with a group of 15 well-respected climate policy experts, three of whom signed the open letter in 2024.
Among them is leading Swedish climate and sustainability scientist Johan Rockström who has strong ideas about how to make COPs function better, including a switch to majority voting. He told the same press briefing nothing stands in the way of this, because the rules of procedure for making decisions at COPs have never been formally agreed.
Still, to get away from the default setting of consensus would require agreement on a new system that may be impossible to achieve given the rise in bullying tactics by fossil fuel heavyweights.
Comment: The UN climate process was built for negotiation – now it must support implementation
The deliberations with the high-level policy gurus, as reflected in a summary of June’s session in Bonn, largely echo what’s already happening organically, calling for stronger partnerships and accountability both in and between the Action Agenda and negotiations. It doesn’t mention voting.
A general overview of the reform exercise says that “improving and optimizing the [UN climate] process over the medium to long term… will be critical to fostering trust, enhancing collaboration, and catalyzing increased ambition”.
In the short term, don’t hold your breath for anything concrete on reform at COP31 but watch for signs in what ends up dominating the headlines from Türkiye.
The post Editor’s Desk: COP reform is happening quietly, behind the headlines appeared first on Climate Home News.
Editor’s Desk: COP reform is happening quietly, behind the headlines