title: The Environmental Legacy of Modern Tropical Deforestation.
abstract: Tropical deforestation has caused a significant share of carbon emissions and species losses, but historical patterns have rarely been explicitly considered when estimating these impacts [1]. A deforestation event today leads to a time-delayed future release of carbon, from the eventual decay either of forest products or of slash left at the site [2]. Similarly, deforestation often does not result in the immediate loss of species, and communities may exhibit a process of "relaxation" to their new equilibrium over time [3]. We used a spatially explicit land cover change model [4] to reconstruct the annual rates and spatial patterns of tropical deforestation that occurred between 1950 and 2009 in the Amazon, in the Congo Basin, and across Southeast Asia. Using these patterns, we estimated the resulting gross vegetation carbon emissions [2, 5] and species losses over time [6]. Importantly, we accounted for the time lags inherent in both the release of carbon and the extinction of species. We show that even if deforestation had completely halted in 2010, time lags ensured there would still be a carbon emissions debt of at least 8.6 petagrams, equivalent to 5-10 years of global deforestation, and an extinction debt of more than 140 bird, mammal, and amphibian forest-specific species, which if paid, would increase the number of 20(th)-century extinctions in these groups by 120%. Given the magnitude of these debts, commitments to reduce emissions and biodiversity loss are unlikely to be realized without specific actions that directly address this damaging environmental legacy.
authors.affiliation: Imperial College of London, Silwood Park Campus, Buckhurst Road, Ascot SL5 7PY, UK; German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5E, 04103 Leipzig, Germany. Electronic address: isabel.rosa@idiv.de.
authors.forename: Isabel M D
authors.initials: IM
authors.lastname: Rosa
authors.affiliation: Computational Science Laboratory, Microsoft Research, Cambridge CB1 2FB, UK.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Smith
authors.affiliation: Imperial College of London, Silwood Park Campus, Buckhurst Road, Ascot SL5 7PY, UK; Institute of Zoology, Zoological Society of London, Regent's Park, London NW1 4RY, UK.
authors.forename: Oliver R
authors.initials: OR
authors.lastname: Wearn
authors.affiliation: Computational Science Laboratory, Microsoft Research, Cambridge CB1 2FB, UK; Google Deepmind, 5 New Street Square, London EC4A 3TW, UK.
authors.forename: Drew
authors.initials: D
authors.lastname: Purves
authors.affiliation: Imperial College of London, Silwood Park Campus, Buckhurst Road, Ascot SL5 7PY, UK.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Ewers
mesh_terms: D000350:Africa, Central; D001210:Asia, Southeastern; D044822:Biodiversity; D002244:Carbon / Q000032:analysis; D003247:Conservation of Natural Resources; D004784:Environmental Monitoring; D053476:Extinction, Biological; D065928:Forests; D008962:Models, Theoretical; D013020:South America; D014197:Trees / Q000502:physiology; D014329:Tropical Climate
chemical_list: D002244:Carbon
keywords: carbon debt; species extinction debt; time lags; tropical deforestation