Abstract
The Amazon forest is fire sensitive, but, where fires were uncommon as a natural disturbance, deforestation and drought are accelerating fire occurrences, which threaten the integrity of the tropical forest, the carbon cycle and air quality. Fire emissions depend on fuel amount and type, moisture conditions and burning behaviour. Higher-resolution satellite data have helped more accurately map global burnt areas; however, the effects of fuels on the combustion process and on the composition of fire emissions remain uncertain in current fire emissions inventories. By using multiple Earth observation-based approaches, here we show that total fire emissions in the Amazon and Cerrado biomes are dominated by smouldering combustion of woody debris. The representation of woody debris and surface litter presents a critical uncertainty in fire emissions inventories and global vegetation models. For the fire season 1 August to 31 October 2020, for which all approaches are available, we found \(372^{605}_{277}\,\mathrm{Tg}\) (median and range across approaches) of dry matter burnt, corresponding to carbon monoxide emissions of \(39.1^{59}_{27}\,\mathrm{Tg}\). Our results emphasize how Earth observation approaches for fuel and fire dynamics and of atmospheric trace gases reduce uncertainties of fire emission estimates. The findings enable diagnosing the representation of fuels, wildfire combustion and its effects on atmospheric composition and the carbon cycle in global vegetation–fire models.
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Data availability
Data from the TUD.S4F, KNMI.S5p and GFA.S4F approaches are available from the Sense4Fire Experimental Database v02 at https://sense4fire.eu/database/ and archived at https://doi.org/10.25532/OPARA-688. GFA.S4F is archived and will be additionally updated via Zenodo at https://doi.org/10.5281/zenodo.14338495 (ref. 51). Fuel maps and field data for the Cerrado from L22 are available as well at https://doi.org/10.25532/OPARA-688. GFED500m is available via Zenodo at https://doi.org/10.5281/zenodo.7229674 (ref. 52). REFIT.AC is available via Zenodo at https://doi.org/10.5281/zenodo.14204054 (ref. 53). GFAS is available from the CAMS Atmosphere Data Store at https://ads.atmosphere.copernicus.eu/. Model results from JULES, OCN and ORCHIDEE are available via Zenodo at https://doi.org/10.5281/zenodo.14287612 (ref. 54). Input data to the TUD.S4F approach are available from the references and sources provided in Supplementary Table 1. Coastlines in all maps are taken from the Natural Earth 1:50 m dataset (https://www.naturalearthdata.com/).
Code availability
The source code of the TUD.S4F satellite data model fusion approach is available via Zenodo at https://doi.org/10.5281/zenodo.14274229 (ref. 55). We recommend that potential users contact the corresponding author to discuss how to use the code.
References
Feng, X. et al. How deregulation, drought and increasing fire impact Amazonian biodiversity. Nature 597, 516–521 (2021).
Drüke, M. et al. Fire may prevent future Amazon forest recovery after large-scale deforestation. Commun. Earth Environ. 4, 248 (2023).
Heinrich, V. H. A. et al. The carbon sink of secondary and degraded humid tropical forests. Nature 615, 436–442 (2023).
Gatti, L. V. et al. Amazonia as a carbon source linked to deforestation and climate change. Nature 595, 388–393 (2021).
Gatti, L. V. et al. Increased Amazon carbon emissions mainly from decline in law enforcement. Nature 621, 318–323 (2023).
Cobelo, I. et al. The impact of wildfires on air pollution and health across land-use categories in Brazil over a 16-year period. Environ. Res. 224, 115522 (2023).
Aragão, L. E. O. C. et al. 21st century drought-related fires counteract the decline of Amazon deforestation carbon emissions. Nat. Commun. 9, 536 (2018).
Andela, N. et al. Tracking and classifying Amazon fire events in near real time. Sci. Adv. 8, eabd2713 (2022).
Rosan, T. M. et al. Fragmentation-driven divergent trends in burned area in Amazonia and Cerrado. Front. For. Glob. Change 5, 801408 (2022).
Rodrigues, A. A. et al. Cerrado deforestation threatens regional climate and water availability for agriculture and ecosystems. Glob. Change Biol. 28, 6807–6822 (2022).
van der Velde, I. R. et al. Biomass burning combustion efficiency observed from space using measurements of CO and NO2 by the TROPOspheric Monitoring Instrument (TROPOMI). Atmos. Chem. Phys. 21, 597–616 (2021).
Rego, F. C., Morgan, P., Fernandes, P. & Hoffman, C. Fire Science: From Chemistry to Landscape Management (Springer International Publishing, 2021); https://doi.org/10.1007/978-3-030-69815-7
Andreae, M. O. & Merlet, P. Emission of trace gases and aerosols from biomass burning. Glob. Biogeochem. Cycles 15, 955–966 (2001).
Kaiser, J. W. et al. Biomass burning emissions estimated with a global fire assimilation system based on observed fire radiative power. Biogeosciences 9, 527–554 (2012).
Seiler, W. & Crutzen, P. J. Estimates of gross and net fluxes of carbon between the biosphere and the atmosphere from biomass burning. Climatic Change 2, 207–247 (1980).
van der Werf, G. R. et al. Global fire emissions estimates during 1997–2016. Earth Syst. Sci. Data 9, 697–720 (2017).
van Wees, D. et al. Global biomass burning fuel consumption and emissions at 500 m spatial resolution based on the Global Fire Emissions Database (GFED). Geosci. Model Dev. 15, 8411–8437 (2022).
de Laat, A., Huijnen, V., Andela, N. & Forkel, M. Assessment of satellite observation-based wildfire emissions inventories using TROPOMI data and IFS-COMPO model simulations. EGUsphere https://doi.org/10.5194/egusphere-2024-732 (2024).
Fawcett, D, et al. Carbon fluxes from different fire types in the Amazon and Cerrado biomes quantified using Earth-observation based modelling. EGU General Assembly https://doi.org/10.5194/egusphere-egu23-6173 (2023).
Silveira, M. V. F., Silva-Junior, C. H. L., Anderson, L. O. & Aragão, L. E. O. C. Amazon fires in the 21st century: the year of 2020 in evidence. Glob. Ecol. Biogeogr. 31, 2026–2040 (2022).
Lizundia-Loiola, J., Otón, G., Ramo, R. & Chuvieco, E. A spatiotemporal active-fire clustering approach for global burned area mapping at 250 m from MODIS data. Remote Sens. Environ. 236, 111493 (2020).
Ramo, R. et al. African burned area and fire carbon emissions are strongly impacted by small fires undetected by coarse resolution satellite data. Proc. Natl Acad. Sci. USA 118, e2011160118 (2021).
Andreae, M. O. Emission of trace gases and aerosols from biomass burning – an updated assessment. Atmos. Chem. Phys. 19, 8523–8546 (2019).
Gomes, L., Miranda, H. S., Silvério, D. V. & Bustamante, M. M. C. Effects and behaviour of experimental fires in grasslands, savannas, and forests of the Brazilian Cerrado. For. Ecol. Manage. 458, 117804 (2020).
Carvalho, J. A. Jr et al. Biomass fire consumption and carbon release rates of rainforest-clearing experiments conducted in northern Mato Grosso, Brazil. J. Geophys. Res. Atmos. 106, 17877–17887 (2001).
van Leeuwen, T. T. et al. Biomass burning fuel consumption rates: a field measurement database. Biogeosciences 11, 7305–7329 (2014).
Scaranello, M. A. S. et al. Estimation of coarse dead wood stocks in intact and degraded forests in the Brazilian Amazon using airborne lidar. Biogeosciences 16, 3457–3474 (2019).
Leite, R. V. et al. Large scale multi-layer fuel load characterization in tropical savanna using GEDI spaceborne lidar data. Remote Sens. Environ. 268, 112764 (2022).
Hyde, J. C., Smith, A. M. S., Ottmar, R. D., Alvarado, E. C. & Morgan, P. The combustion of sound and rotten coarse woody debris: a review. Int. J. Wildland Fire 20, 163–174 (2011).
Zhao, W., van Logtestijn, R. S. P., van der Werf, G. R., van Hal, J. R. & Cornelissen, J. H. C. Disentangling effects of key coarse woody debris fuel properties on its combustion, consumption and carbon gas emissions during experimental laboratory fire. For. Ecol. Manage. 427, 275–288 (2018).
Chen, Y. et al. Multi-decadal trends and variability in burned area from the fifth version of the Global Fire Emissions Database (GFED5). Earth Syst. Sci. Data 15, 5227–5259 (2023).
Li, F. et al. Historical (1700–2012) global multi-model estimates of the fire emissions from the Fire Modeling Intercomparison Project (FireMIP). Atmos. Chem. Phys. 19, 12545–12567 (2019).
Lapola, D. M. et al. The drivers and impacts of Amazon forest degradation. Science 379, eabp8622 (2023).
Xu, X., Jia, G., Zhang, X., Riley, W. J. & Xue, Y. Climate regime shift and forest loss amplify fire in Amazonian forests. Glob. Change Biol. 26, 5874–5885 (2020).
Castellanos, P., Boersma, K. F. & van der Werf, G. R. Satellite observations indicate substantial spatiotemporal variability in biomass burning NOx emission factors for South America. Atmos. Chem. Phys. 14, 3929–3943 (2014).
Targino, A. C. et al. Surface ozone climatology of South Eastern Brazil and the impact of biomass burning events. J. Environ. Manage. 252, 109645 (2019).
Lamsal, L. N. et al. Application of satellite observations for timely updates to global anthropogenic NOx emission inventories. Geophys. Res. Lett. 38, L05810 (2011).
Huijnen, V. et al. Fire carbon emissions over maritime southeast Asia in 2015 largest since 1997. Sci. Rep. 6, 26886 (2016).
Chuvieco, E. et al. Generation and analysis of a new global burned area product based on MODIS 250 m reflectance bands and thermal anomalies. Earth Syst. Sci. Data 10, 2015–2031 (2018).
Andela, N. et al. The Global Fire Atlas of individual fire size, duration, speed and direction. Earth Syst. Sci. Data 11, 529–552 (2019).
Giglio, L., Boschetti, L., Roy, D. P., Humber, M. L. & Justice, C. O. The Collection 6 MODIS burned area mapping algorithm and product. Remote Sens. Environ. 217, 72–85 (2018).
Giglio, L., Schroeder, W. & Justice, C. O. The collection 6 MODIS active fire detection algorithm and fire products. Remote Sens. Environ. 178, 31–41 (2016).
Fawcett, D. et al. Earth observation enables high resolution modelling of fire related emissions in the Amazon and Cerrado biomes. In IAF Global Space Conference on Climate Change (GLOC, 2023, accessed 26 Feb. 2024); https://dl.iafastro.directory/event/GLOC-2023/paper/75102/
Santoro, M. et al. The global forest above-ground biomass pool for 2010 estimated from high-resolution satellite observations. Earth Syst. Sci. Data 13, 3927–3950 (2021).
Hersbach, H. et al. The ERA5 global reanalysis. Q. J. R. Meteorol. Soc. 146, 1999–2049 (2020).
Friedlingstein, P. et al. Global Carbon Budget 2021. Earth Syst. Sci. Data 14, 1917–2005 (2022).
Dlugokencky, E. & Tans, P. Trends in atmospheric carbon dioxide (NOAA/ESRL, 2022).
Chini, L. et al. Land-use harmonization datasets for annual global carbon budgets. Earth Syst. Sci. Data 13, 4175–4189 (2021).
Hansen, M. C. et al. High-resolution global maps of 21st-century forest cover change. Science 342, 850–853 (2013).
Falster, D. S. et al. BAAD: a Biomass And Allometry Database for woody plants. Ecology 96, 1445 (2015).
Andela, N. et al. Tracking and classifying Amazon fire events in near-real time. Zenodo https://doi.org/10.5281/zenodo.14338495 (2025).
van Wees, D. et al. Model data for 'Global biomass burning fuel consumption and emissions at 500-m spatial resolution based on the Global Fire Emissions Database (GFED)'. Zenodo https://doi.org/10.5281/zenodo.7229674 (2024).
Fawcett, D. REFIT.AC v22 fire emissions for Forkel et al. 'Burning of woody debris dominates fire emissions in the Amazon and Cerrado'. Zenodo https://doi.org/10.5281/zenodo.14204054 (2024).
Sitch, S. Diagnostic satellite burned area simulations from three Dynamic Global Vegetation Models. Zenodo https://doi.org/10.5281/zenodo.14287612 (2024).
Forkel, M. Satellite data-model fusion appproach for fuel loads, fuel moisture, fuel consumption and fire emissions (S4F). Zenodo https://doi.org/10.5281/zenodo.14274229 (2024).
Acknowledgements
The work has been funded by the European Space Agency (ESA) through the Sense4Fire project (M.F., C.W., C.M., D.K., V.H., A.d.L., N.A., D.v.W.) and through the NRT-Extremes project (S.S., J.G.D.S., D.F., A.B., S.Z., P.C., W.L.). Data collection and fuel mapping efforts over the Brazilian Cerrado were funded by the Brazilian National Council for Scientific and Technological Development (CNPq, grant 442640/2018-8, CNPq/Prevfogo-Ibama 33/2018) and NASA Carbon Monitoring System (CMS, grant 22-CMS22-0015) (R.L., C.S., C.K.). E.K. was supported by Fondazione Cassa di Risparmio di Padova e Rovigo (CARIPARO). We thank the TUD Center for Interdisciplinary Digital Sciences (CIDS)/Department Information services and high-performance computing (ZIH) for providing data processing and storage resources.
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M.F., N.A., V.H., A.d.L. and S.P. conceived and designed the work. N.A., A.d.L., V.H., D.K., C.W., and D.v.W. acquired satellite data. C.K., R.L., C.S. acquired and provided field measurements. M.F., N.A., P.C., V.H., J.W.K., D.K., E.K. and R.L. analysed and interpreted data and results. All authors contributed to the development of model approaches, methods or conducted model experiments: M.F., D.K., C.M., C.W. (TUD.S4F); N.A., D.v.W. (GFA.S4F); V.H., A.d.L. (KNMI.S5p); D.v.W. (GFED500m); D.F., S.S. (REFIT.AC); S.S., J.G.D.S. (JULES); A.B., S.Z. (OCN); P.C., W.L. (ORCHIDEE); C.K., R.L., C.S. (L22.GEDI). M.F. and C.W. drafted the paper with section inputs from N.A., A.d.L., D.F., V.H., S.S. and D.v.W. M.F., P.C., E.K., V.H., C.M. and S.P. revised the paper.
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Extended data
Extended Data Fig. 1 Simplified structure of the TUD.S4F approach to estimate fuel load, fuel moisture, fuel consumption and fire emissions.
Various satellite datasets are used as forcing (top) or for parameter calibration and model validation (right).
Extended Data Fig. 2 Uncertainty in estimated fire emissions and coarse woody debris from the TUD.S4F approach based on a regional analysis.
(a) Estimated CO emissions for the period 1st August to 31st October 2020 from the TUD.S4F default estimate. (b) Uncertainty estimate of CO emissions defined as the root mean square difference of all factorial model experiments relative to the default TUD.S4F estimate. (c) Time series of CO emissions with the estimated uncertainty (that is range across all factorial model experiments show in d). (d-g) The factorial experiments include a model run with fixed emission factors (+fixEF), with using the FireCCI51 burnt area dataset (+no small fires), 56 model experiments that were created by sampling different parameter sets (Parameter uncertainty), and five experiments that represent different assumptions about timber harvest (harvest index = 0 to 80%, that is no extraction of wood to strong extraction of wood). The root mean squared difference of factorial experiments relative to the TUD.S4F default result is written above the horizontal lines, whereby each line indicates the comparison for which the RMSD was calculated. For example, parameter uncertainty is 34, 32 and 38 % for regional total CO emissions (d), dry matter burnt (e), and coarse woody debris (f), respectively. The different assumptions about how much wood is extracted from a site during timber harvest are the main source of uncertainty. (g) Despite those uncertainties, the relationship between coarse woody debris and the CO emission factor is highly consistent across all factorial experiments.
Extended Data Fig. 3 Comparison of total CO emission from all approaches.
Maps of total fire CO emissions (g CO m−2) between 1st August and 31st October 2020 from the different fire emissions approaches.
Extended Data Fig. 4 Difference in total CO emissions from each approach relative to the KNMI.S5p approach.
Difference in total CO (g CO m−2) are for the period 1st August – 31st October 2020.
Extended Data Fig. 5 Emergent relationships between dry matter burnt from dynamic global vegetation models and Earth observation-based approaches (TUD.S4F and GFED500m) with burnt area, woody debris and litter, and vegetation biomass.
(a) Multi-model uncertainty in annual total dry matter burnt defined as the normalized root mean square difference of the three DGVMs (JULES, OCN and ORCHIDEE). Maps were spatially aggregated to the resolution of the coarsest model (1.875°longitude x 1.25°latitude). (b-d) Emergent relationships of dry matter burnt with (b) annual total burnt area, (c) with woody debris and litter, and (d) with vegetation biomass. Emergent relationships are partial dependencies calculated by predicting dry matter burnt from burnt area, biomass, and woody debris/litter using Generalized Additive Models with spline smooths applied to each EO or DGVM approach’s outputs. The relationship for woody debris and litter is missing for JULES due to unavailable model output. Tick marks on the x-axis represent deciles (minimum to maximum) of each predictor variable’s statistical distribution from TUD.S4F outputs. The vertical range on the right visualizes the amplitude of the partial effect in TUD.S4F, shown in (c) and (d) for comparison.
Extended Data Fig. 6 Comparison of fire dry matter burnt and CO emissions from all approaches for the period 2014–2020 based on monthly aggregated time series.
Error bands for TUD.S4F (red shade) and KNMI.S5p (blue shade) are the respective uncertainty estimates (see Methods).
Extended Data Fig. 7 Comparison of different fuel components for the Cerrado biome from three satellite-based approaches (TUD.S4F, GFED500m, and Leite et al.28 [L22.GEDI].
The line-shaped patterns in L22.GEDI are from the spatial sampling of the GEDI sensor. Please note that the fuel components of the three approaches are not fully comparable and hence we report for each approach also the original name of a fuel component. For example, WDfuel in L22 includes woody biomass for trees with diameter at breast height > 10 cm while TUD.S4F treats shrubs as small trees. SUfuels in L22 includes all dead herbaceous and woody plant material at the surface and hence a direct assignment of SUfuel to the litter or woody debris classes in TUD.S4F and GFED500m is not possible. nRMSD is the normalized root mean squared difference relative to the mean value of the three approaches (or two for leaf biomass) and serves as measure of uncertainty across the multiple approaches. The numbers in each map represent the median value and percentiles 5% and 95% of the values in each map.
Extended Data Fig. 8 Distribution of (a) modified combustion efficiency and (b) emission factor for PM2.5 for different fire types from the TUD.S4F approach with dynamic emission factors in comparison to field and laboratory measurements for tropical forests (For) and savannahs and grasslands (Sav) from Andreae (2019) [A19].
Horizontal lines are mean values, boxes are highest density intervals, and grey points in A19 are individual reported values.
Supplementary information
Supplementary Information
Detailed description of the TUD.S4F approach (Supplementary Information 1), a description of the uncertainty calculation for the KNMI.S5p approach (Supplementary Information 2) and Supplementary Figs. 1–11.
Supplementary Video 1
Regional example of fuel and fire dynamics at 333 × 333 m resolution for a deforestation area in Pará, Brazil as estimated with the TUD.S4F approach. a, Leaf area index from Proba-V and Sentinel-3 (green background) and burnt area from FireCCI51 (2014–2019) and GFA.S4F (2020). Clusters of individual fires are highlighted by circles, whereby circle size reflects the derived fire radiative energy and blue and red colours indicate smouldering and flaming combustion with modified combustion efficiency (MCE) below and above the regional average MCE, respectively. b, Time series of total emissions and fuel consumption for the region shown in a. c, Estimated tree biomass and fuel consumption of tree biomass (wood and leaves). d, Estimated woody debris load and fuel consumption of woody debris. e, Estimated herbaceous biomass and fuel consumption of herbaceous biomass. f, Estimated litter load and fuel consumption of litter.
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Forkel, M., Wessollek, C., Huijnen, V. et al. Burning of woody debris dominates fire emissions in the Amazon and Cerrado. Nat. Geosci. 18, 140–147 (2025). https://doi.org/10.1038/s41561-024-01637-5
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DOI: https://doi.org/10.1038/s41561-024-01637-5
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