Suppression of rainfall by fires in African drylands

Abstract Fire is a widespread agent of disturbance in African drylands, but the impact of fire on local precipitation remains poorly understood and large‐scale observational evidence has been lacking. Here we link fire to a reduction in precipitation across African drylands. Using 15 years of satellite observations over continental sub‐Saharan Africa, we find that more extensive and later dry season fires lead to wet season rainfall deficits of up to 30 mm (~10%). The effect is stronger in the Southern Hemisphere, a signal we attribute to the later timing of fires in the dry season. Given the coupling between rainfall, fuel loads, and fire in African drylands, a negative interannual feedback may arise between fire and precipitation, whereby fires suppress precipitation, thereby reducing fuel load and fire in the subsequent season. The reduced fuel load would, in turn, increase precipitation, completing the feedback loop. This feedback may contribute to a pervasive negative autocorrelation observed in Southern Hemisphere annual rainfall.