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
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Lena Luig is the head of the International Agricultural Policy Division at the Heinrich Böll Foundation, a member of the Global Alliance for the Future of Food. Anna Lappé is the Executive Director of the Global Alliance for the Future of Food.
As toxic clouds loom over Tehran and Beirut from the US and Israel’s bombardment of oil depots and civilian infrastructure in the region’s ongoing war, the world is once again witnessing the not-so-subtle connections between conflict, hunger, food insecurity and the vulnerability of global food systems dependent on fossil fuels, dominated by a few powerful countries and corporations.
The conflict in Iran is having a huge impact on the world’s fertilizer supply. The Strait of Hormuz is a critical trade route in the region for nearly half of the global supply of urea, the main synthetic fertilizer derived from natural gas through the conversion of ammonia.
With the Strait impacted by Iran’s blockades, prices of urea have shot up by 35% since the war started, just as planting season starts in many parts of the world, putting millions of farmers and consumers at risk of increasing production costs and food price spikes, resulting in food insecurity, particularly for low-income households. The World Food Programme has projected that an extra 45 million people would be pushed into acute hunger because of rises in food, oil and shipping costs, if the war continues until June.
Pesticides and synthetic fertilizer leave system fragile
On the face of it, this looks like a supply chain issue, but at the core of this crisis lies a truth about many of our food systems around the world: the instability and injustice in the very design of systems so reliant on these fossil fuel inputs for our food.
At the Global Alliance, a strategic alliance of philanthropic foundations working to transform food systems, we have been documenting the fossil fuel-food nexus, raising alarm about the fragility of a system propped up by fossil fuels, with 15% of annual fossil fuel use going into food systems, in part because of high-cost, fossil fuel-based inputs like pesticides and synthetic fertilizer. The Heinrich Böll Foundation has also been flagging this threat consistently, most recently in the Pesticide Atlas and Soil Atlas compendia.
We’ve seen this before: Russia’s invasion of Ukraine in 2022 sparked global disruptions in fertilizer supply and food price volatility. As the conflict worsened, fertilizer prices spiked – as much from input companies capitalizing on the crisis for speculation as from real cost increases from production and transport – triggering a food price crisis around the world.
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Since then, fertilizer industry profit margins have continued to soar. In 2022, the largest nine fertilizer producers increased their profit margins by more than 35% compared to the year before—when fertilizer prices were already high. As Lena Bassermann and Dr. Gideon Tups underscore in the Heinrich Böll Foundation’s Soil Atlas, the global dependencies of nitrogen fertilizer impacted economies around the world, especially state budgets in already indebted and import-dependent economies, as well as farmers across Africa.
Learning lessons from the war in Ukraine, many countries invested heavily in renewable energy and/or increased domestic oil production as a way to decrease dependency on foreign fossil fuels. But few took the same approach to reimagining domestic food systems and their food sovereignty.
Agroecology as an alternative
There is another way. Governments can adopt policy frameworks to encourage reductions in synthetic fertilizer and pesticide use, especially in regions that currently massively overuse nitrogen fertilizer. At the African Union fertilizer and Soil Health Summit in 2024, African leaders at least agreed that organic fertilizers should be subsidized as well, not only mineral fertilizers, but we can go farther in actively promoting agricultural pathways that reduce fossil fuel dependency.
In 2024, the Global Alliance organized dozens of philanthropies to call for a tenfold increase in investments to help farmers transition from fossil fuel dependency towards agroecological approaches that prioritize livelihoods, health, climate, and biodiversity.
In our research, we detail the huge opportunity to repurpose harmful subsidies currently supporting inputs like synthetic fertilizer and pesticides towards locally-sourced bio-inputs and biofertilizer production. We know this works: There are powerful stories of hope and change from those who have made this transition, despite only receiving a fraction of the financing that industrial agriculture receives, with evidence of benefits from stable incomes and livelihoods to better health and climate outcomes.
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Inspiring examples abound: G-BIACK in Kenya is training farmers how to produce their own high-quality compost; start-ups like the Evola Company in Cambodia are producing both nutrient-rich organic fertilizer and protein-rich animal feed with black soldier fly farming; Sabon Sake in Ghana is enriching sugarcane bagasse – usually organic waste – with microbial agents and earthworms to turn it into a rich vermicompost.
These efforts, grounded in ecosystems and tapping nature for soil fertility and to manage pest pressures, are just some of the countless examples around the world, tapping the skill and knowledge of millions of farmers. On a national and global policy level, the Agroecology Coalition, with 480+ members, including governments, civil society organizations, academic institutions, and philanthropic foundations, is supporting a transition toward agroecology, working with natural systems to produce abundant food, boost biodiversity, and foster community well-being.
Fertilizer industry spins “clean” products
We must also inoculate ourselves from the fertilizer industry’s public relations spin, which includes promoting the promise that their products can be produced without heavy reliance on fossil fuels. Despite experts debunking the viability of what the industry has dubbed “green hydrogen” or “green or clean ammonia”, the sector still promotes this narrative, arguing that these are produced with resource-intensive renewable energy or Carbon Capture and Storage (CCS), a costly and unreliable technology for reducing emissions.
As we mourn this conflict’s senseless destruction and death, including hundreds of children, we also recognize that peace cannot mean a return to business-as-usual. We need to upend the systems that allow the richest and most powerful to have dominion over so much.
This includes fighting for a food system that is based on genuine sovereignty and justice, free from dependency on fossil fuels, one that honors natural systems and puts power into the hands of communities and food producers themselves.
The post Middle East war is another wake-up call for fossil fuel-reliant food systems appeared first on Climate Home News.
Middle East war is another wake-up call for fossil fuel-reliant food systems
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