Global biomass burning fuel consumption and emissions at 500 m spatial resolution based on the Global Fire Emissions Database (GFED)

Abstract

Abstract. In fire emission models, the spatial resolution of both the modelling framework and the satellite data used to quantify burned area can have considerable impact on emission estimates. Consideration of this sensitivity is especially important in areas with heterogeneous land cover and fire regimes and when constraining model output with field measurements. We developed a global fire emissions model with a spatial resolution of 500 m using MODerate resolution Imaging Spectroradiometer (MODIS) data. To accommodate this spatial resolution, our model is based on a simplified version of the Global Fire Emissions Database (GFED) modelling framework. Tree mortality as a result of fire, i.e. fire-related forest loss, was modelled based on the overlap between 30 m forest loss data and MODIS burned area and active fire detections. Using this new 500 m model, we calculated global average carbon emissions from fire of 2.1±0.2 (±1σ interannual variability, IAV) Pg C yr−1 during 2002–2020. Fire-related forest loss accounted for 2.6±0.7 % (uncertainty range =1.9 %–3.3 %) of global burned area and 24±6 % (uncertainty range =16 %–31 %) of emissions, indicating that fuel consumption in forest fires is an order of magnitude higher than the global average. Emissions from the combustion of soil organic carbon (SOC) in the boreal region and tropical peatlands accounted for 13±4 % of global emissions. Our global fire emissions estimate was higher than the 1.5 Pg C yr−1 from GFED4 and similar to 2.1 Pg C yr−1 from GFED4s. Even though GFED4s included more burned area by accounting for small fires undetected by the MODIS burned area mapping algorithm, our emissions were similar to GFED4s due to higher average fuel consumption. The global difference in fuel consumption could mainly be explained by higher SOC emissions from the boreal region as constrained by additional measurements. The higher resolution of the 500 m model also contributed to the difference by improving the simulation of landscape heterogeneity and reducing the scale mismatch in comparing field measurements to model grid cell averages during model calibration. Furthermore, the fire-related forest loss algorithm introduced in our model led to more accurate and widespread estimation of high-fuel-consumption burned area. Recent advances in burned area detection at resolutions of 30 m and finer show a substantial amount of burned area that remains undetected with 500 m sensors, suggesting that global carbon emissions from fire are likely higher than our 500 m estimates. The ability to model fire emissions at 500 m resolution provides a framework for further improvements with the development of new satellite-based estimates of fuels, burned area, and fire behaviour, for use in the next generation of GFED.

High resolution data reveal a surge of biomass loss from temperate and Atlantic pine forests, seizing the 2022 fire season distinctiveness in France

“…It should be noted that this AGB product considers all the biomass compartments, including foliage and understory vegetation, whereas our AGB product considers only woody tree biomass. Finally, AGB-L obtained in this study was compared to the (burned) wood carbon pool of the global 500-m resolution fire emissions dataset provided by Van Wees et al ( 2022), based on the GFED framework and with biomass cycling simulated by the CASA model (van Wees et al, 2022). All these alternative products have a coarser resolution than our burned area and AGB-L maps (Table 1).…”

“…Integrative models of fire emissions combining burned area datasets, land cover, seasonal ecosystem functioning, and a simulation of the biomass carbon pools affected by fires have been applied globally at 0.5° resolution, in the GFED model (Randerson et al, 2017). A finer resolution of 500 m was recently achieved with this method and constitutes a key information for global studies (van Wees et al, 2022).…”

Carbon uptake in Eurasian boreal forests dominates the high‐latitude net ecosystem carbon budget

“…Altogether, the Arctic‐boreal terrestrial NECB was −566 Tg C year −1 for tundra, boreal forest and boreal wetlands, and −815 Tg C year −1 when also including boreal grassland/shrublands (Figure 6). Adding in estimates of annual aquatic CH 4 emissions from open water bodies across the tundra and boreal zone (Johnson et al, 2021, 2022; totaling 5.3 Tg C‐CH 4 year −1 ), our estimate of regional CH 4 uptake (−3.9 Tg C‐CH 4 year −1 ), and regional emissions of CO 2 , CH 4 from fire (average of 170 Tg C year −1 , based on van Wees et al, 2022), modified the NECB sink status by 21% (totaling −640 Tg C year −1 ). Overall, the Eurasian boreal forest region had the largest NECB sink (~ −199 Tg C year −1 ).…”

“…Our estimate of Arctic‐boreal NECB, when considering terrestrial NEE and CH 4 emissions (and not factoring in CH 4 uptake) was −815 Tg C year −1 with boreal wetland and tundra CH 4 offsetting the NEE sink by only 4%. Accounting for aquatic CH 4 emissions from open water (using recent estimates from Johnson et al, 2021, 2022), and emissions from fire (van Wees et al, 2022), reduced the NECB sink status by 21%.…”

“…We report trends with caution, given the relatively short (13‐year) study record. Lastly, to examine the impact of aquatic CH 4 and terrestrial fire carbon emissions on the regional budgets, we included information from the Johnson et al (2021, 2022) open water CH 4 emissions products, and the Global Fire Emissions Database version 5 (GFEDv5; van Wees et al, 2022) for a more complete assessment of NECB.…”