title: Committed changes in tropical tree cover under the projected 21st century climate change.
abstract: Warming and drought pose a serious threat to tropical forest. Yet the extent of this threat is uncertain, given the lack of methods to evaluate the forest tree cover changes under future climate predicted by complex dynamic vegetation models. Here we develop an empirical approach based on the observed climate space of tropical trees to estimate the maximum potential tropical tree cover (MPTC) in equilibrium with a given climate. We show that compared to present-day (2000-2009) conditions, MPTC will be reduced by 1 to 15% in the tropical band under equilibrium future (2090-2099) climate conditions predicted by 19 IPCC climate models. Tropical forests are found to regress or disappear mainly in the current transition zones between forest and savanna ecosystems. This climate pressure on tropical forests, added to human-caused land use pressure, poses a grand challenge to the sustainability of the world's largest biomass carbon pool.
authors.affiliation: College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
authors.forename: Zhenzhong
authors.initials: Z
authors.lastname: Zeng
authors.forename: Shilong
authors.initials: S
authors.lastname: Piao
authors.forename: Anping
authors.initials: A
authors.lastname: Chen
authors.forename: Xin
authors.initials: X
authors.lastname: Lin
authors.forename: Huijuan
authors.initials: H
authors.lastname: Nan
authors.forename: Junsheng
authors.initials: J
authors.lastname: Li
authors.forename: Philippe
authors.initials: P
authors.lastname: Ciais