Mark Parrington

The global geography, behaviour, and impact of fires are shifting, as spatially varying human influences interact with a visibly changing climate. The State of Wildfires project systematically tracks global and regional fire activity, analyses the causes of prominent extreme wildfire events for three focal regions, and projects the likelihood of similar events under future climate scenarios. During the March 2025–February 2026 fire season, global burned area (BA) was 18 % below the 2002–2024 average and global fire carbon (C) emissions were also 20 %–31 % below average, making it one of the lowest years on record. Yet this globally low fire year still produced widespread regional impacts. Canada experienced a third consecutive extreme fire year, with national fire C emissions at nearly triple the average since 2002, 70 000 evacuations, and reported direct losses of USD 360 million. In the Midwestern Canadian Shield Forests, the epicentre of Canada's anomalous season, we find that anthropogenic climate change has nearly doubled (likely synthesis range 0.33–44.9, median 1.85) the likelihood of extreme fire weather in this region and made the observed BA around 10 times more likely during July–August 2025. BA extent in the region is found to be 9 times greater. Many parts of Europe also experienced record or high-ranking BA and fire C emissions, including in Spain, Portugal, and the UK, and a record USD 4.11 billion of physical assets were exposed to fire across the continent. Direct fatalities occurred in Türkiye (17), Spain (8), Portugal (6), Cyprus (2), Greece (1) and France (1), and evacuations in Türkiye, Spain, and Greece totalled over 110 000. In the Northwest Iberian Peninsula, we find that extreme fire weather over August 2025 was around 3 times (virtually certain modelled range 0.14–657, median 3.63) more likely due to climate change. Under a high-emissions scenario (SSP3-7.0), fires of the same return interval are likely to burn about 78 % more area by the end of the century, with some projections within the same scenario suggesting increases of around sevenfold. In Chile and northwest Argentina, January–February 2026 fires caused 23 fatalities, displaced 55 000 people and threatened a UNESCO World Heritage Site. In the Chilean Temperate Forests and Matorral, the epicentre, we find that BA was around two times larger due to anthropogenic climate change. Across all focal regions in this report, the conditions for extreme fire developed gradually through months of precipitation deficits, cumulative drying and, in the case of Northwest Iberia, antecedent fuel accumulation aided by preceding wet periods. Continued climate change is expected to intensify these hydroclimatic extremes. However, comparison of SSP3-7.0 with SSP5-8.5 suggests that projected end-of-century extreme BA events in our focal regions are 4 %–23 % smaller than under the very high-emissions futures that were once considered plausible.. Meeting the Paris targets (SSP1-2.6) would further reduce BA during these events by 5 %–36 % across our focal regions. By integrating expertise from across the wildfire community with state-of-the-art observations, data, and modelling, this annual report advances understanding of regional wildfire extremes and their drivers, providing evidence to inform policy, preparedness, mitigation, adaptation, and broader societal benefit. Fifteen new and updated datasets created in this report are available from the State of Wildfires Project's Zenodo community (https://zenodo.org/communities/stateofwildfiresproject/, last access: 23 October 2026).

The global geography, behaviour, and impact of fires are shifting, as spatially varying human influences interact with a visibly changing climate. The State of Wildfires project systematically tracks global and regional fire activity, analyses the causes of prominent extreme wildfire events for three focal regions, and projects the likelihood of similar events under future climate scenarios. During the March 2025–February 2026 fire season, global burned area (BA) was 18 % below the 2002–2024 average and global fire carbon (C) emissions were also 20–31 % below average, making it one of the lowest years on record. Yet this globally low fire year still produced widespread regional impacts. Canada experienced a third consecutive extreme fire year, with national fire C emissions at nearly triple the average since 2002, 70,000 evacuations, and reported direct losses of USD 360 million. In the Midwestern Canadian Shield Forests, the epicentre of Canada’s anomalous season, we find that anthropogenic climate change has doubled the likelihood of extreme fire weather in this region and made the observed BA around 61 times more likely during July–August 2025, while BA extent in the region is 46 times greater. Many parts of Europe also experienced record or high-ranking BA and fire C emissions, including in Spain, Portugal, and the UK, and a record USD 4.11 billion of physical assets were exposed to fire across the continent. Direct fatalities occurred in Türkiye (17), Spain (8), Portugal (6), Cyprus (2), Greece (1) and France (1), and evacuations in Türkiye, Spain, and Greece totalled over 110,000. In the Northwest Iberian Peninsula, we find that extreme fire weather over August 2025 was around 3 times more likely due to climate change. Under a high-emissions scenario (SSP3-7.0), fires of the same return interval are likely to burn about 78 % more area by the end of the century, with some projections within the same scenario suggesting increases of around sevenfold. In Chile and northwest Argentina, January–February 2026 fires caused 23 fatalities, displaced 55,000 people and threatened a UNESCO World Heritage Site. In the Chilean Temperate Forests and Matorral, the epicentre, we find that BA was around 36 % larger due to anthropogenic climate change. Across all focal regions in this report, the conditions for extreme fire developed gradually through months of precipitation deficits, cumulative drying and, in the case of Northwest Iberia, antecedent fuel accumulation aided by preceding wet periods. Continued climate change is expected to intensify these hydroclimatic extremes, yet mitigation has already reduced projected end-of-century wildfire risk: under a high-end emissions pathway (SSP3-7.0), the extreme BA events in our focal regions are projected to be 4–23 % smaller than they would have been under a worst-case emissions scenario no longer considered credible (SSP5-8.5). Meeting the Paris targets (SSP1-2.6) would further reduce BA during these events by 5–36 % across our focal regions. By integrating expertise from across the wildfire community with state-of-the-art observations, data, and modelling, this annual report advances understanding of regional wildfire extremes and their drivers, providing evidence to inform policy, preparedness, mitigation, adaptation, and broader societal benefit. Seventeen new and updated datasets created in this report are available from the State of Wildfires Project's Zenodo community (https://zenodo.org/communities/stateofwildfiresproject/).

This study investigates long-term wildfire emissions and smoke-plume geospatial characteristics in Greece by analyzing a multi-pollutant dataset spanning January 2003 to August 2025. Details of emissions of carbon monoxide (CO), carbon dioxide (CO₂), methane (CH₄), particulate matter (PM_2.5), organic carbon (OC), and black carbon (BC) were derived from the Global Fire Assimilation System (GFAS), which converts MODIS fire radiative power into trace gas and aerosol fluxes at 0.1° resolution, and also accounts for the land type. Burned-area statistics from the European Forest Fire Information System (EFFIS) were used for cross-validation. Data were processed into daily, monthly, annual, and cumulative time series, with spatial mapping at the municipality scale and information regarding long-term trends. The analysis shows that while there are several sizeable wildfire events in the country every year, the bulk of the total of Greek wildfire emissions for the last 23 years is attributable to a few extreme fire seasons (2007, 2021, and 2023) that produced abrupt emission surges and accounted for a disproportionate share of national totals. Analysis of spatial data identifies the areas of Evia, East Attica, Messinia, and Evros as persistent emission hotspots. Although wildfire CO₂ emissions are generally a minor fraction of Greece’s anthropogenic totals (<5%), they reached 15–17% during peak fire years. Plume-injection height analysis reveals that most smoke remains below ~1 km but can reach 3–6 km during extreme events, facilitating long-range transport. Overall, the dataset demonstrates a shift toward more intense and concentrated wildfire events in recent years, highlighting both their growing climatic relevance and their acute impacts on regional air quality.

Climate change is increasing the frequency and intensity of extreme wildfires globally, yet our understanding of these high-impact events remains uneven and shaped by media attention and regional research biases. The State of Wildfires project systematically tracks global and regional fire activity of each annual fire season, analyses the causes of prominent extreme wildfire events, and projects the likelihood of similar events occurring in future climate scenarios. This, its second annual report, covers the March 2024 to February 2025 fire season. During the 2024–2025 fire season, fire-related carbon (C) emissions totalled 2.2 Pg C, 9 % above average and the sixth highest on record since 2003, despite below-average global burned area (BA). Extreme fire seasons in South America's rainforests, dry forests, and wetlands and in Canada's boreal forests pushed up the global C emissions total. Fire C emissions were over 4 times above average in Bolivia, 3 times above average in Canada, and ∼ 50 % above average in Brazil and Venezuela. Wildfires in 2024–2025 caused 100 fatalities in Nepal, 34 in South Africa, and 31 in Los Angeles, with additional fatalities reported in Canada, Côte d'Ivoire, Portugal, and Türkiye. The Eaton and Palisades fires in Southern California caused 150 000 evacuations and USD 140 billion in damages. Communities in Brazil, Bolivia, Southern California, and northern India were exposed to fine particulate matter at concentrations 13–60 times WHO's daily air quality standards. We evaluated the causes and predictability of four extreme wildfire episodes from the 2024–2025 fire season, including in Northeast Amazonia (January–March 2024), the Pantanal–Chiquitano border regions of Brazil and Bolivia (August–September 2024), Southern California (January 2025), and the Congo Basin (July–August 2024). Anomalous weather created conditions for these regional extremes, while fuel availability and human ignitions shaped spatial patterns and temporal fire dynamics. In the three tropical regions, prolonged drought was the dominant fire enabler, whereas in California, extreme heat, wind, and antecedent fuel build-up were compounding enablers. Our attribution analyses show that climate change made extreme fire weather in Northeast Amazonia 30–70 times more likely, increasing BA roughly 4-fold compared to a scenario without climate change. In the Pantanal–Chiquitano, fire weather was 4–5 times more likely, with 35-fold increases in BA. Meanwhile, our analyses suggest that BA was 25 times higher in Southern California due to climate change. The Congo Basin's fire weather was 3–8 times more likely with climate change, with a 2.7-fold increase in BA. Socioeconomic changes since the pre-industrial period, including land-use change, also likely increased BA in Northeast Amazonia. Our models project that events on the scale of 2024–2025 will become up to 57 %, 34 %, and 50 % more frequent than in the modern era in Northeast Amazonia, the Pantanal–Chiquitano, and the Congo Basin, respectively, under a medium–high scenario (SSP370) by 2100. Climate action can limit the added risk, with frequency increases held to below 15 % in all three regions under a strong mitigation scenario (SSP126). In Southern California, the future trajectory of extreme fire likelihood remains highly uncertain due to poorly constrained climate–vegetation–fire interactions influencing fuel moisture, though our models suggest that risk may decline in future. This annual report from the State of Wildfires project integrates and advances cutting-edge fire observations and modelling with regional expertise to track changing global wildfire hazard, guiding policy and practice towards improved preparedness, mitigation, adaptation, and societal benefit. Thirteen new datasets and model codebases presented in this work are available from the State of Wildfires Project's Zenodo community, including updated annual statistics on wildfire extent (Jones et al., 2025; https://doi.org/10.5281/zenodo.15525674), outputs from modelling of fire causality using PoF model (Di Giuseppe, 2025; https://doi.org/10.24433/CO.8570224.v1) and codebase for the extreme event attribution/projections model, ConFLAME (Barbosa et al., 2025a, https://doi.org/10.5281/zenodo.16790787).

Accurate estimates of biomass burning (BB) emissions are of great importance worldwide due to the impacts of these emissions on human health, ecosystems, air quality, and climate. Atmospheric modeling efforts to represent these impacts require BB emissions as a key input. This paper is presented by the Biomass Burning Uncertainty: Reactions, Emissions and Dynamics (BBURNED) activity of the International Global Atmospheric Chemistry project and largely based on a workshop held in November 2023. The paper reviews 9 of the BB emissions datasets widely used by the atmospheric chemistry community, all of which rely heavily on Moderate Resolution Imaging Spectroradiometer (MODIS) satellite observations of fires scheduled to be discontinued at the end of 2025. In this time of transition away from MODIS to new fire observations, such as those from the Visible Infrared Imaging Radiometer Suite (VIIRS) satellite instruments, we summarize the contemporary status of BB emissions estimation and provide recommendations on future developments. Development of global BB emissions datasets depends on vegetation datasets, emission factors, and assumptions of fire persistence and phase, all of which are highly uncertain with high degrees of variability and complexity and are continually evolving areas of research. As a result, BB emissions datasets can have differences on the order of factor 2–3, and no single dataset stands out as the best for all regions, species, and times. We summarize the methodologies and differences between BB emissions datasets. The workshop identified 5 key recommendations for future research directions for estimating BB emissions and quantifying the associated uncertainties: development and uptake of satellite burned area products from VIIRS and other instruments; mapping of fine scale heterogeneity in fuel type and condition; identification of spurious signal detections and information gaps in satellite fire radiative power products; regional modeling studies and comparison against existing datasets; and representation of the diurnal cycle and plume rise in BB emissions.

Climate change is increasing the frequency and intensity of extreme wildfires globally, yet our understanding of these high-impact events remains uneven and shaped by media attention and regional research biases. The State of Wildfire Project systematically tracks and analyses global fire activity and this, its second annual report, covers the March 2024 to February 2025 fire season. During the 2024–25 fire season, fire-related carbon (C) emissions were totalled 2.2 Pg C, 9 % above average and the 6th highest on record since 2003, despite below-average global burned area (BA; 3.7 million km2). Extreme fire seasons in South America’s rainforests, dry forests and wetlands, and in Canada’s boreal forests pushed up the global C emissions total. Fire C emissions were over four times above average in Bolivia, three times above average in Canada, and ~50 % above average in Brazil and Venezuela. Wildfires in 2024–25 caused 100 fatalities in Nepal, 34 in South Africa, and 30 in Los Angeles, with additional fatalities reported in Canada, Côte d’Ivoire, Portugal, and Turkey. The Eaton and Palisades fires in Southern California caused 150,000 evacuations and US$140 billion in damages. Communities in Brazil, Bolivia, Southern California, and Northern India were exposed to fine particulate matter at concentrations 13–60 times WHO’s daily air quality standards. We evaluated the causes and predictability of four extreme wildfire episodes from the 2024–25 fire season, including in Northeast Amazonia (January–March 2024), the Pantanal-Chiquitano border regions of Brazil and Bolivia (July–September 2024), Southern California (January 2025), and the Congo Basin (July–August 2024). Anomalous weather created conditions for these regional extremes, while fuel availability and human ignitions shaped spatial patterns and temporal fire dynamics. In the three tropical regions, prolonged drought was the dominant fire enabler, whereas in California, extreme heat, wind, and antecedent fuel build-up were the dominant enablers. Our attribution analyses show that climate change made extreme fire weather in Northeast Amazonia 30–70 times more likely, increasing burned area roughly fourfold compared to a scenario without climate change. In the Pantanal–Chiquitano, fire weather was 4–5 times more likely, with up to 35-fold increases in burned area. In Southern California, climate change made larger burned area 89 % more likely, with burned area up to 25 times higher. The Congo Basin’s fire weather was 3–8 times more likely with climate change, with a 2.7-fold increase in burned area. Socioeconomic changes since the pre-industrial period, including land-use change, also likely increased burned area in Northeast Amazonia. Our models project that events on the scale of 2024–25 will become up to 57 %, 34 %, and 50 % more frequent than in the modern era in Northeast Amazonia, the Pantanal-Chiquitano, and the Congo Basin, respectively, under a middle-of-the-road scenario (SSP370). Climate action can limit the added risk, with frequency increases kept below 15 % in all three regions under a strong mitigation scenario (SSP126). In Southern California, the future trajectory of extreme fire likelihood remains highly uncertain due to poorly constrained climate-vegetation-fire interactions influencing fuel moisture, though our models suggest that risk may decline in future. This annual report from the State of Wildfires Project integrates and advances cutting-edge fire observations and modelling with regional expertise to track changing global wildfire hazard, guiding policy and practice towards improved preparedness, mitigation, adaptation, and societal benefit. Thirteen new datasets and model codebases presented in this work are available from the State of Wildfires Project’s Zenodo community (https://zenodo.org/communities/stateofwildfiresproject, last access: 11 August 2025).

Open biomass burning has major impacts globally and regionally on atmospheric composition. Fire emissions include particulate matter, tropospheric ozone precursors, and greenhouse gases, as well as persistent organic pollutants, mercury, and other metals. Fire frequency, intensity, duration, and location are changing as the climate warms, and modelling these fires and their impacts is becoming more and more critical to inform climate adaptation and mitigation, as well as land management. Indeed, the air pollution from fires can reverse the progress made by emission controls on industry and transportation. At the same time, nearly all aspects of fire modelling – such as emissions, plume injection height, long-range transport, and plume chemistry – are highly uncertain. This paper outlines a multi-model, multi-pollutant, multi-regional study to improve the understanding of the uncertainties and variability in fire atmospheric science, models, and fires' impacts, in addition to providing quantitative estimates of the air pollution and radiative impacts of biomass burning. Coordinated under the auspices of the Task Force on Hemispheric Transport of Air Pollution, the international atmospheric modelling and fire science communities are working towards the common goal of improving global fire modelling and using this multi-model experiment to provide estimates of fire pollution for impact studies. This paper outlines the research needs, opportunities, and options for the fire-focused multi-model experiments and provides guidance for these modelling experiments, outputs, and analyses that are to be pursued over the next 3 to 5 years. The paper proposes a plan for delivering specific products at key points over this period to meet important milestones relevant to science and policy audiences.

The study of wildfires is crucial to understanding the Earth system, as severe wildfire events can lead to intense degradation of nature and property. The record-breaking 2023 Canadian wildfire event best represents this, with approximately 5% of the total forest area of Canada burned [1] [2], resulting in biomass burning (BB) emissions quantitatively comparable to the annual fossil fuel emissions of large nations [3], and with the highest Canadian carbon emissions on record [4]. Increased mean temperatures along with decreased humidity in the region due to climate change are considered responsible for this record series of wildfires [5], as increasing mean temperatures along with decreasing humidity in the region led to increased fire risk.Large amounts of carbonaceous aerosols can exert substantial atmospheric radiative forcing, thus it is important to study the consequences of these emissions on large-scale atmospheric composition and meteorological behavior. In this work, global and local atmospheric impacts of this historic wildfire event are analyzed using the EC-Earth3 earth system model [6] in its standard AerChem configuration. BB emissions from the Copernicus Atmosphere Monitoring Service (CAMS) Global Fire Assimilation System (GFAS) were used as input in the model to produce two 10-member ensembles simulations, with and without the 2023 Canadian wildfire emissions. The results are analyzed, and the differences in various modelled atmospheric quantities between the two ensembles are spatially cross-correlated to determine connections between atmospheric anomalies and wildfire intrusions.Modelled monthly changes in radiative effects, cloud cover, large-scale circulation, and temperature patterns throughout the North Hemisphere and Canada are found as a result of the 2023 BB emissions, and the mechanisms via which these can be caused are discussed and explained. These changes include the long-range transport of the BB pollutants in the troposphere and the stratosphere with marked impacts on cloud cover and on temperatures at low and high altitudes, differential cooling over the Canadian region due to a dual influence of direct and indirect effects of AOD increases, and even large-scale circulation anomalies which led to cooling as far as in Eastern Siberia. We find that the modelled temperature anomalies between the two ensembles caused by the wildfire-generated aerosols can be as intense as -5.44 °C locally, while the modelled average hemispheric temperature anomaly is equal to -0.91 °C.[1] "Fire Statistics". Canadian Interagency Forest Fire Centre. Retrieved January 4, 2024.[2] “The State of Canada’s Forests: Annual Report”. 2022. Canadian Minister of Natural Resources.[3] Byrne, Brendan, et al. "Carbon emissions from the 2023 Canadian wildfires" Nature. 2024 835-839.[4] “Copernicus: Emissions from Canadian wildfires the highest on record – smoke plume reaches Europe”. Atmosphere Monitoring Service, Copernicus. Retrieved January 4, 2024.[5] Barnes, Clair, et al. "Climate change more than doubled the likelihood of extreme fire weather conditions in eastern Canada" 2023.[6] Döscher, Ralf, et al. "The EC-earth3 Earth system model for the climate model intercomparison project 6." Geoscientific Model Development Discussions. 2021 1-90.