African burned area and fire carbon emissions are strongly impacted by small fires undetected by coarse resolution satellite data

Fires burn an area comparable to Europe each year, emitting greenhouse gases and aerosols. We compared burned area (BA) based on 20-m resolution images with a BA derived from 500-m data. It represents an 80% increase in BA in sub-Saharan Africa, responsible for about 70% of global BA. This difference is predominately (87%) attributed to small fires (<100 ha), which account for 41% of total BA but only for 5% in coarse-resolution products. We found that African fires were responsible for emissions of 1.44 PgC, 31-101% higher than previous estimates and representing 14% of global CO₂ emissions from fossil fuel burning. We conclude that small fires are critically important in characterizing the most important disturbance agent on a global scale.