Tropical deforestation and forest degradation have important environmental impacts. Extensive air pollution from deforestation fires is a serious health issue across the tropics, but large uncertainties remain in its quantification. Deforestation alters rainfall, both through changes to the land surface and through the impacts of smoke from deforestation fires. However, the magnitude and sign of the rainfall response to deforestation is not clear because underlying land-atmosphere interactions are poorly understood and because the net response is a result of multiple, complex interactions that have not been fully assessed. The impacts of deforestation on atmospheric composition and climate causes a complex set of biosphere interactions resulting in potential Earth system feedbacks. These feedbacks have not yet been quantified and so their importance is not known. Despite recent progress, many of these key interactions between deforestation, fire, atmospheric composition and climate remain poorly understood. In particular, previous studies focused on individual interactions; the combined impacts of land surface change and smoke from fires on air quality and climate have not been quantified. Action to mitigate the air quality and climate impacts of deforestation and associated fires is hindered by these substantial gaps in understanding. DECAF addressed this important challenge, delivering improved process-level knowledge of the impacts of deforestation on atmospheric composition and climate and a step change in our understanding of the impact of deforestation on the Earth system.
The primary aim of DECAF was to make a step change in our understanding of the impacts of deforestation on the Earth system through the interactions and feedbacks between tropical deforestation, fires, atmospheric composition and climate. DECAF is the first integrated study of the combined interactions and feedbacks between tropical deforestation, fire, atmospheric composition and climate. DECAF has the following objectives:
To address this important challenge, DECAF exploited new information from laboratory experiments, in-situ and satellite observations in combination with state-of-the-art numerical models.
DECAF provided evidence of the impacts of tropical deforestation on local and regional climate and air quality. We found that tropical deforestation causes local and regional warming and drying (reduced rainfall). Fires associated with deforestation causes regional air pollution with negative health impacts. Overall, the work provides evidence of the local and regional benefits of polices that aim to reduce tropical deforestation.
