A decline in the area burned globally by wildfires over the 20th century due to land-use change has almost entirely been offset by the increase caused by global warming, a new study says.
The paper, published in Nature Climate Change, is the first attribution study to assess the impacts of climate change and land-use change on “global burned area”.
It finds that changes in population distribution and land use over the 20th century – including forest fragmentation and the conversion of land for urban development and agriculture – have suppressed wildfires, driving down global burned area by 19%.
However, this decline has been hindered by human-caused warming, which has expanded the area burned by 16% through increasingly hot and dry conditions across much of the world.
As a result, the global burned area has declined just 5% over the past 100 years.
Despite the worldwide decline overall, the study finds that climate change has driven increases in burned area of 29% in south-eastern South America, 22% in northern Australia, 18% in west Siberia and 15% in western North America.
This study is the “key missing piece to the puzzle of tracking anthropogenic emissions”, according to Dr Matthew Jones – an independent researcher who was not involved in the study.
Jones, who works with on the annual Global Carbon Budget (GCP), tells Carbon Brief that this study is a “major step forward in modelling the extent of additional, human-related fires”. He notes that until now, projects like the GCB have “been forced to assume that all fire emissions are natural, therefore underestimating the effect of people on the global carbon cycle”.
Burned area paradox
Australia’s “black summer” bushfires of 2020-21 are one of the continent’s most intense and damaging fire seasons on record. The fires burned around almost 25m hectares of land, killed more than 30 people and released more CO2 than the combined annual emissions of over 100 countries.
Researchers from the World Weather Attribution (WWA) service published a “rapid attribution” study on Australia’s wildfires. They find the likelihood of Australia experiencing weather conditions like those in the lead-up to its 2020-21 fires has increased by at least 30% since 1900 as a result of climate change.
Similarly, WWA found that climate change more than doubled the likelihood of extreme fire weather conditions that led to unprecedented fires in eastern Canada in 2023. And the hot, dry and windy conditions that drove the devastating Pantanal wildfires in 2024 were 40% more intense due to climate change.
Attribution studies make it clear that climate change is making individual wildfires more intense and frequent. However, data shows that, overall, the area burned globally by fires is decreasing.
Dr Matthew Jones is an independent researcher who works with the Natural Environment Research Council and Global Carbon Project. He is the lead author of a study published last week, which finds that forest fire carbon emissions increased by 60% globally over 2001-23.
He tells Carbon Brief there climate change is does not provide the whole picture when it comes to global burned area, noting that human activity can impact wildfires in many ways:
“Wildfires are a natural phenomenon, but they are made increasingly likely by human-induced climate change and they are also influenced by people, who manage much of Earth’s land area and also alter rates of fire ignition.
“Fire scientists have long grappled with the troublesome task of separating out the additional fires that people are causing, over and above the fires that would have happened naturally.”
Attributing burned area
Seppe Lampe is a doctoral student at Vrije University Brussels department of water and climate and co-lead author on the study. He tells Carbon Brief that “this is the first study that actually attributes and quantifies how much climate change has affected burned area all over the world”.
The authors use seven “fire-vegetation models” from the Inter-Sectoral Impact Model Intercomparison Project to carry out the attribution study, which compares wildfires in today’s climate with wildfires in a counterfactual world without human-caused climate change.
To assess the impact of climate change on global burned area, the authors run models of the present-day climate (2003-19), both with and without the impacts of climate change. They then compare the results to isolate the impacts of climate change on global burned area.
To study the impact of “direct human forcing” – defined as land-use change, land management and population density – they compare simulations of the world in the early-industrial period (1901-17) and a present day world (2003-19) without the impact of climate change. In these simulations, the authors do not include any long-term changes in climate, so the only differences are in land use and population change.
The maps below show the percentage change in burned area due to climate change (top), direct human forcing (middle) and both (bottom). Red indicates an increase in percentage burned area and blue indicates a decrease. White indicates that there has been little change in the percentage of burned area. The map divides the world into hexagonal regions, as used by the Intergovernmental Panel on Climate Change (IPCC).
Climate and land-use change
The study finds that climate change has driven an increase in burned area in most IPCC regions, with only eight of the 42 regions showing a decrease in burned area due to the changing climate.
Lampe explains that the climate-driven decrease in burned area in regions such as south-east Asia could be due to factors such as changing rainfall patterns.
Many regions have seen more than a 10% increase in burned area due to climate change alone, including all IPCC regions in Australia and several regions in South America, Siberia and North America, the study adds.
The authors find that on average, climate change has driven a 16% increase in burned area globally and increased the probability of experiencing months with above-average global burned area by 22%.
The area of land that would be burned in the two most-active fire months of the year in a world without climate change is now expected for four months every year, the authors add.
The authors also find that the impact of climate change on burned area is accelerating over time, increasing most rapidly after the 1970s. Central Australia has seen the greatest increase.
Conversely, the authors find that changes in direct human forcing factors since the early industrial period have driven a 19.1% decrease in burned area.
This is due to landscape fragmentation, a reduction in fuel for fires – often seen when landscapes are converted from natural areas into urban areas or cropland – and deliberate fire management and suppression techniques, according to the study.
The decrease in burned area is mainly seen in savannah, grasslands and croplands – particularly in equatorial Asia and tropical North Africa – Lampe tells Carbon Brief. He adds:
“The global signal of burned area is actually 70% determined by what’s going on in the African savannahs. And there we see more and more savannahs being turned into cropland, which causes a decline in burned area.”
Overall, the study finds a 5% reduction in global burned area since the early 20th century.
‘Major step forward’
The study shows that without the “mitigating influences” of land-use change, global burned area would probably be even higher today.
This work is a “major step forward in modelling the extent of additional, human-related fires”, Jones tells Carbon Brief. He adds:
“Up until now, projects like the Global Carbon Budget have struggled to estimate how people influence the climate through wildfire emissions. We have been forced to assume that all fire emissions are natural, therefore underestimating the effect of people on the global carbon cycle.”
He explains that this study is the “key missing piece to the puzzle of tracking anthropogenic emissions”.
Prof David Bowman is an Australian Research Council laureate fellow and the director of the transdisciplinary Fire Centre at the University of Tasmania. He tells Carbon Brief that the approach used in this study seems “valid”, but adds that wildfire modelling is “extraordinarily difficult”.
He points out a few important assumptions and caveats in the “useful” study – for example, that the authors do not consider the intensity of fires.
Bowman also warns that the decline in global burned area “has been used for political purposes deflecting attention from the escalating wildfire crisis”.
Dr Maria Barbosa – a researcher at the Universidade Federal de São Carlos, who was not involved in the study – tells Carbon Brief that the study “provides valuable insights into how fire regimes are likely to shift”.
Barbosa warns that “we are currently failing to prepare for the upcoming fire seasons”, and says that governments need to invest in early warning systems, improve land-use planning to reduce fire risks and strengthen policies for forest management and restoration.
Lampe tells Carbon Brief that the findings of this study could help to inform regional policymakers and could “have significance for loss and damage”.
The post Climate change almost wipes out decline in global area burned by wildfires appeared first on Carbon Brief.
Climate change almost wipes out decline in global area burned by wildfires
Drought and heatwaves occurring together – known as “compound” events – have “surged” across the world since the early 2000s, a new study shows.
Compound drought and heat events (CDHEs) can have devastating effects, creating the ideal conditions for intense wildfires, such as Australia’s “Black Summer” of 2019-20 where bushfires burned 24m hectares and killed 33 people.
The research, published in Science Advances, finds that the increase in CDHEs is predominantly being driven by events that start with a heatwave.
The global area affected by such “heatwave-led” compound events has more than doubled between 1980-2001 and 2002-23, the study says.
The rapid increase in these events over the last 23 years cannot be explained solely by global warming, the authors note.
Since the late 1990s, feedbacks between the land and the atmosphere have become stronger, making heatwaves more likely to trigger drought conditions, they explain.
One of the study authors tells Carbon Brief that societies must pay greater attention to compound events, which can “cause severe impacts on ecosystems, agriculture and society”.
Compound events
CDHEs are extreme weather events where drought and heatwave conditions occur simultaneously – or shortly after each other – in the same region.
These events are often triggered by large-scale weather patterns, such as “blocking” highs, which can produce “prolonged” hot and dry conditions, according to the study.
Prof Sang-Wook Yeh is one of the study authors and a professor at the Ewha Womans University in South Korea. He tells Carbon Brief:
“When heatwaves and droughts occur together, the two hazards reinforce each other through land-atmosphere interactions. This amplifies surface heating and soil moisture deficits, making compound events more intense and damaging than single hazards.”
CDHEs can begin with either a heatwave or a drought.
The sequence of these extremes is important, the study says, as they have different drivers and impacts.
For example, in a CDHE where the heatwave was the precursor, increased direct sunshine causes more moisture loss from soils and plants, leading to a drought.
Conversely, in an event where the drought was the precursor, the lack of soil moisture means that less of the sun’s energy goes into evaporation and more goes into warming the Earth’s surface. This produces favourable conditions for heatwaves.
The study shows that the majority of CDHEs globally start out as a drought.
In recent years, there has been increasing focus on these events due to the devastating impact they have on agriculture, ecosystems and public health.
In Russia in the summer of 2010, a compound drought-heatwave event – and the associated wildfires – caused the death of nearly 55,000 people, the study notes.
The record-breaking Pacific north-west “heat dome” in 2021 triggered extreme drought conditions that caused “significant declines” in wheat yields, as well as in barley, canola and fruit production in British Columbia and Alberta, Canada, says the study.
Increasing events
To assess how CDHEs are changing, the researchers use daily reanalysis data to identify droughts and heatwaves events. (Reanalysis data combines past observations with climate models to create a historical climate record.) Then, using an algorithm, they analyse how these events overlap in both time and space.
The study covers the period from 1980 to 2023 and the world’s land surface, excluding polar regions where CDHEs are rare.
The research finds that the area of land affected by CDHEs has “increased substantially” since the early 2000s.
Heatwave-led events have been the main contributor to this increase, the study says, with their spatial extent rising 110% between 1980-2001 and 2002-23, compared to a 59% increase for drought-led events.
The map below shows the global distribution of CDHEs over 1980-2023. The charts show the percentage of the land surface affected by a heatwave-led CDHE (red) or a drought-led CDHE (yellow) in a given year (left) and relative increase in each CDHE type (right).
The study finds that CDHEs have occurred most frequently in northern South America, the southern US, eastern Europe, central Africa and south Asia.
Threshold passed
The authors explain that the increase in heatwave-led CDHEs is related to rising global temperatures, but that this does not tell the whole story.
In the earlier 22-year period of 1980-2001, the study finds that the spatial extent of heatwave-led CDHEs rises by 1.6% per 1C of global temperature rise. For the more-recent period of 2022-23, this increases “nearly eightfold” to 13.1%.
The change suggests that the rapid increase in the heatwave-led CDHEs occurred after the global average temperature “surpasse[d] a certain temperature threshold”, the paper says.
This threshold is an absolute global average temperature of 14.3C, the authors estimate (based on an 11-year average), which the world passed around the year 2000.
Investigating the recent surge in heatwave-leading CDHEs further, the researchers find a “regime shift” in land-atmosphere dynamics “toward a persistently intensified state after the late 1990s”.
In other words, the way that drier soils drive higher surface temperatures, and vice versa, is becoming stronger, resulting in more heatwave-led compound events.
Daily data
The research has some advantages over other previous studies, Yeh says. For instance, the new work uses daily estimations of CDHEs, compared to monthly data used in past research. This is “important for capturing the detailed occurrence” of these events, says Yeh.
He adds that another advantage of their study is that it distinguishes the sequence of droughts and heatwaves, which allows them to “better understand the differences” in the characteristics of CDHEs.
Dr Meryem Tanarhte is a climate scientist at the University Hassan II in Morocco, and Dr Ruth Cerezo Mota is a climatologist and a researcher at the National Autonomous University of Mexico. Both scientists, who were not involved in the study, agree that the daily estimations give a clearer picture of how CDHEs are changing.
Cerezo-Mota adds that another major contribution of the study is its global focus. She tells Carbon Brief that in some regions, such as Mexico and Africa, there is a lack of studies on CDHEs:
“Not because the events do not occur, but perhaps because [these regions] do not have all the data or the expertise to do so.”
However, she notes that the reanalysis data used by the study does have limitations with how it represents rainfall in some parts of the world.
Compound impacts
The study notes that if CDHEs continue to intensify – particularly events where heatwaves are the precursors – they could drive declining crop productivity, increased wildfire frequency and severe public health crises.
These impacts could be “much more rapid and severe as global warming continues”, Yeh tells Carbon Brief.
Tanarhte notes that these events can be forecasted up to 10 days ahead in many regions. Furthermore, she says, the strongest impacts can be prevented “through preparedness and adaptation”, including through “water management for agriculture, heatwave mitigation measures and wildfire mitigation”.
The study recommends reassessing current risk management strategies for these compound events. It also suggests incorporating the sequences of drought and heatwaves into compound event analysis frameworks “to enhance climate risk management”.
Cerezo-Mota says that it is clear that the world needs to be prepared for the increased occurrence of these events. She tells Carbon Brief:
“These [risk assessments and strategies] need to be carried out at the local level to understand the complexities of each region.”
The post Heatwaves driving recent ‘surge’ in compound drought and heat extremes appeared first on Carbon Brief.
Heatwaves driving recent ‘surge’ in compound drought and heat extremes
Greenhouse Gases
DeBriefed 6 March 2026: Iran energy crisis | China climate plan | Bristol’s ‘pioneering’ wind turbine
Welcome to Carbon Brief’s DeBriefed.
An essential guide to the week’s key developments relating to climate change.
This week
Energy crisis
ENERGY SPIKE: US-Israeli attacks on Iran and subsequent counterattacks across the Middle East have sent energy prices “soaring”, according to Reuters. The newswire reported that the region “accounts for just under a third of global oil production and almost a fifth of gas”. The Guardian noted that shipping traffic through the strait of Hormuz, which normally ferries 20% of the world’s oil, “all but ground to a halt”. The Financial Times reported that attacks by Iran on Middle East energy facilities – notably in Qatar – triggered the “biggest rise in gas prices since Russia’s full-scale invasion of Ukraine”.
‘RISK’ AND ‘BENEFITS’: Bloomberg reported on increases in diesel prices in Europe and the US, speculating that rising fuel costs could be “a risk for president Donald Trump”. US gas producers are “poised to benefit from the big disruption in global supply”, according to CNBC. Indian government sources told the Economic Times that Russia is prepared to “fulfil India’s energy demands”. China Daily quoted experts who said “China’s energy security remains fundamentally unshaken”, thanks to “emergency stockpiles and a wide array of import channels”.
‘ESSENTIAL’ RENEWABLES: Energy analysts said governments should cut their fossil-fuel reliance by investing in renewables, “rather than just seeking non-Gulf oil and gas suppliers”, reported Climate Home News. This message was echoed by UK business secretary Peter Kyle, who said “doubling down on renewables” was “essential” amid “regional instability”, according to the Daily Telegraph.
China’s climate plan
PEAK COAL?: China has set out its next “five-year plan” at the annual “two sessions” meeting of the National People’s Congress, including its climate strategy out to 2030, according to the Hong Kong-based South China Morning Post. The plan called for China to cut its carbon emissions per unit of gross domestic product (GDP) by 17% from 2026 to 2030, which “may allow for continued increase in emissions given the rate of GDP growth”, reported Reuters. The newswire added that the plan also had targets to reach peak coal in the next five years and replace 30m tonnes per year of coal with renewables.
ACTIVE YET PRUDENT: Bloomberg described the new plan as “cautious”, stating that it “frustrat[es] hopes for tighter policy that would drive the nation to peak carbon emissions well before president Xi Jinping’s 2030 deadline”. Carbon Brief has just published an in-depth analysis of the plan. China Daily reported that the strategy “highlights measures to promote the climate targets of peaking carbon dioxide emissions before 2030”, which China said it would work towards “actively yet prudently”.
Around the world
- EU RULES: The European Commission has proposed new “made in Europe” rules to support domestic low-carbon industries, “against fierce competition from China”, reported Agence France-Presse. Carbon Brief examined what it means for climate efforts.
- RECORD HEAT: The US National Oceanic and Atmospheric Administration has said there is a 50-60% chance that the El Niño weather pattern could return this year, amplifying the effect of global warming and potentially driving temperatures to “record highs”, according to Euronews.
- FLAGSHIP FUND: The African Development Bank’s “flagship clean energy fund” plans to more than double its financing to $2.5bn for African renewables over the next two years, reported the Associated Press.
- NO WITHDRAWAL: Vanuatu has defied US efforts to force the Pacific-island nation to drop a UN draft resolution calling on the world to implement a landmark International Court of Justice (ICJ) ruling on climate, according to the Guardian.
98
The number of nations that submitted their national reports on tackling nature loss to the UN on time – just half of the 196 countries that are part of the UN biodiversity treaty – according to analysis by Carbon Brief.
Latest climate research
- Sea levels are already “much higher than assumed” in most assessments of the threat posed by sea-level rise, due to “inadequate” modelling assumptions | Nature
- Accelerating human-caused global warming could see the Paris Agreement’s 1.5C limit crossed before 2030 | Geophysical Research Letters covered by Carbon Brief
- Future “super El Niño events” could “significantly lower” solar power generation due to a reduction in solar irradiance in key regions, such as California and east China | Communications Earth & Environment
(For more, see Carbon Brief’s in-depth daily summaries of the top climate news stories on Monday, Tuesday, Wednesday,