title: Tropical forests were the primary sources of new agricultural land in the 1980s and 1990s.
abstract: Global demand for agricultural products such as food, feed, and fuel is now a major driver of cropland and pasture expansion across much of the developing world. Whether these new agricultural lands replace forests, degraded forests, or grasslands greatly influences the environmental consequences of expansion. Although the general pattern is known, there still is no definitive quantification of these land-cover changes. Here we analyze the rich, pan-tropical database of classified Landsat scenes created by the Food and Agricultural Organization of the United Nations to examine pathways of agricultural expansion across the major tropical forest regions in the 1980s and 1990s and use this information to highlight the future land conversions that probably will be needed to meet mounting demand for agricultural products. Across the tropics, we find that between 1980 and 2000 more than 55% of new agricultural land came at the expense of intact forests, and another 28% came from disturbed forests. This study underscores the potential consequences of unabated agricultural expansion for forest conservation and carbon emissions.
authors.affiliation: Program on Food Security and the Environment, Stanford University, Stanford, CA 94305, USA. hgibbs@stanford.edu
authors.forename: H K
authors.initials: HK
authors.lastname: Gibbs
authors.forename: A S
authors.initials: AS
authors.lastname: Ruesch
authors.forename: F
authors.initials: F
authors.lastname: Achard
authors.forename: M K
authors.initials: MK
authors.lastname: Clayton
authors.forename: P
authors.initials: P
authors.lastname: Holmgren
authors.forename: N
authors.initials: N
authors.lastname: Ramankutty
authors.forename: J A
authors.initials: JA
authors.lastname: Foley
mesh_terms: D000383:Agriculture / Q000266:history / Q000639:trends; D003247:Conservation of Natural Resources / Q000266:history / Q000639:trends; D018556:Crops, Agricultural / Q000254:growth & development / Q000266:history; D016208:Databases, Factual; D049673:History, 20th Century; D049674:History, 21st Century; D014197:Trees; D014329:Tropical Climate; D014480:United Nations
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