Post-fire soil erosion. How much land are we degrading globally?

Wildfires affect land surface and post-fire geomorphological activity worldwide, increasing surface runoff and soil erosion. Here, we present a global assessment of post-fire soil erosion, considering cumulative wildfire driven geomorphological changes over the last two decades. Stemmed from the largest database on wildfires occurrence and fire severity in the globe, this study estimates global trends of post fire soil erosion together with the recovery of those burned landscapes.

Our results show that when considering multiple wildfire events, global post-fire soil erosion accounts for 8.1 ± 0.72 Pg annually, representing 19% of the global soil erosion budget, and additional 5.1 ± 0.56 Pg soil erosion annually in comparison to pre-fire conditions. Moreover, soil erosion attributed to the first post-fire year represents 31% of the total soil erosion, whereas the remaining share can be attributed to previous wildfires occurrences. In what concerns the spatial distribution, Africa is the continent that is impacted the most in terms of post-fire soil erosion, given its significantly larger burned area.

The results of this study can illustrate the magnitude of post-fire soil erosion globally, and therefore support post-fire management actions towards the mitigation and restoration of affected areas, and policies towards Land Degradation Neutrality.