气候变化领域集成服务门户

While several studies have reported a recent decline in area burned in Africa, the causes of this decline are still not well understood. In this study, we found that from 2002 to 2016 burned area in Africa declined by 18.5%, with the strongest decline (80% of the area) in the Northern Hemisphere. One third of the reduction in burned area occurred in croplands, suggesting that changes in agricultural practices (including cropland expansion) are not the predominant factor behind recent changes in fire extent. Linear models that considered interannual variability in climate factors directly related to biomass productivity and aridity explained about 70% of the decline in burned area in natural land cover. Our results provide evidence that despite the fact that most fires are human-caused in Africa, increased terrestrial moisture during 2002-2016 facilitated declines in fire activity in Africa.

Plain Language Summary The last 15 years of satellite observations indicate a decrease of the global amount of burned area, but this decrease is not evenly distributed geographically. Africa, the continent most affected by fire, has seen the most pronounced decline in burned area. The causes are still poorly understood: the reduction in fire activity could be both due to changes in climate and human factors. We show that only about a third of the reduction in area burned occurred in croplands. The interannual burned area variability in natural lands (forest and nonforest) was linked to climate variables related to moisture availability. We found that about 70% of the reduction of area burned in natural lands can be explained by observed increase in plant-available moisture over the last 15 years. The results point to increased effective precipitation that inhibits flammability, ignition, and fire propagation, especially in wet savannas. These results bring new evidence that, in the complex fire-climate-human relationship, both increased human pressure and changing climate patterns influenced recent fire activity trends in Africa.