Abstract
Updated quantitative estimates are given for the extent of biomass burning (slash-and-burn) for farming worldwide. The atmospheric, climatic, and ecologic consequences of gaseous and particle emissions are also considered. Carbon monoxide and methane from biomass burning contribute to the greenhouse effect, and emissions of nitric oxides and hydrocarbons bring high ozone concentrations to the tropics during the dry season. Smoke particles serve as cloud condensation nuclei and may substantially influence cloud microphysical and optical properties, causing repercussions for the solar radiation budget and the water cycle in the tropics. Widespread burning can also disturb biogeochemical cycles. Pyrodenitrification causes a sizable loss of fixed nitrogen from the tropics of about 10 to 20 teragrams/year.