A shorter dry season is helping reduce wildfires in Africa, according to a new study that found changing rainfall patterns are shrinking the window during which fires can ignite and spread.
The research, published in Geophysical Research Letters, shows that the continent’s dry season has gradually become shorter over the past three decades because it is starting later than it did in the early 1990s.
The shift is being driven by increased rainfall at the beginning of the dry season, leaving vegetation and soils wetter for longer.
“Earlier dry-season rainfall keeps vegetation and soils wetter for longer, reducing fuel dryness and limiting fire ignition and spread,” the researchers wrote in the paper.
The researchers analysed rainfall records from 1990 to 2023 alongside satellite observations of burned areas from 2003 to 2022. They found that the delayed start of the dry season coincided with a widespread decline in the amount of land burned by wildfires across the continent. The largest reductions occurred during the peak fire months—December in northern Africa and August in southern Africa.
Africa accounts for around 70% of the world’s burned area, with most fires occurring during the dry season. Fire is a natural part of many African savanna ecosystems, helping recycle nutrients and maintain grasslands. However, uncontrolled fires also destroy crops and wildlife habitat, threaten nearby communities and release large amounts of carbon into the atmosphere. Scientists have long observed that the area burned by wildfires across Africa has been declining, but the reasons behind that trend have remained unclear.
The new study suggests that the timing of rainfall plays a bigger role than previously recognized.
“Regions and years with wetter early dry seasons generally experience fewer fires and less area burned,” the researchers wrote, adding that “rainfall timing—not just total rainfall—may have contributed to African fire activity.”
According to the study, increased rainfall before and during the dry season delays the drying of grasses and other vegetation that normally serve as fuel for wildfires. With vegetation remaining moist for longer, there is less opportunity for fires to start, spread and grow into large blazes.
The strongest relationship was observed in northern Africa, where shorter dry seasons closely matched shorter fire seasons and significantly smaller burned areas. In southern Africa, the decline in burned area was also evident but the relationship was weaker because climate is only one of several factors influencing fires. Agricultural expansion, human settlements, prescribed burning and fire suppression all play important roles in determining when and where fires occur.
The researchers say their findings highlight the importance of looking beyond annual rainfall totals when assessing wildfire risk. Instead, monitoring when rain falls could provide a better indication of how severe a fire season is likely to be.
“Monitoring early precipitation seasons and developing predictive models can help anticipate fire risk,” they wrote, referring to Africa. They add that accounting for changes in rainfall seasonality “can improve fire prediction and support fire management under a changing climate.”
But authors caution that climate alone does not explain every fire. They note that satellite products may miss some smaller fires and that the study does not distinguish between naturally occurring fires and those deliberately started by people for activities such as land clearing or agriculture.
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