February 2005 / Vol. 55 No. 2 • BioScience 115ArticlesChanges in land cover and in the way people usethe land have become recognized over the last 15 yearsas important global environmental changes in their ownright (Turner 2002). They are also intertwined in many wayswith other environmental issues, such as climate change andcarbon cycle, loss of biodiversity, sustainability of agriculture,and provision of safe drinking water. The international sci-entific community has created new interdisciplinary researchprograms to understand the multiple causes and conse-quences of land-cover and land-use change (Lambin et al.2003). There has been a concomitant rapid expansion in theavailability of data and information. However, there has notyet been a systematic examination, using global and regionalobservations, of the status and trends in terrestrial and coastalland-cover or related important ecosystem processes.The information needs for such a synthesis are diverse.Remote sensing has an important contribution to make indocumenting the actual change in land cover on regionaland global spatial scales from the mid-1970s (Achard et al.2002, DeFries et al. 2002, Lambin et al. 2003). It also has a roleto play in evaluating indices of change in ecological processes,such as net primary production and rainfall use efficiency(Prince et al. 1998). Remote sensing information is found ina widely scattered literature, some of it refereed, some in thegray literature, and some unpublished as yet. There is also an obvious need for good inventory data and statistics about landcover and land-cover change at subnational, national, and in-ternational scales, augmented by a need for subnational andnational indicators of condition, status, and trends of theglobal environment. Finally, there is a need to determine theinterrelationships of remotely sensed and statistical inventorydata, to integrate heterogenous data sources.The tremendous investment in scientific analysis of remotesensing data over the last decade, and the profusion of stud-ies based on other data sources, provides a basis for a synthesis.Although information is not complete globally, several prod-ucts are now available that depict the land cover of Earth glob-ally in the 1990s and in 2000–2001. The same is true forsnapshots of many important regions with substantial land-Erika Lepers and Eric F. Lambin (e-mail: [email protected]) work in theDepartment of Geography, University of Louvain, 3 Place Louis Pasteur, 1348Louvain-la-Neuve, Belgium. Anthony C. Janetos works at the H. John HeinzIII Center for Science, Economics, and the Environment, 1001 PennsylvaniaAvenue, NW, Washington, DC 20004. Ruth DeFries is with the Departmentof Geography and Earth System Science Interdisciplinary Center, Universityof Maryland, College Park, MD 20742. Frederic Achard works at the Institutefor Environment and Sustainability, Joint Research Centre, TP 440, 21020 Ispra, Italy. Navin Ramankutty is with the Center for Sustainability and theGlobal Environment, Nelson Institute for Environmental Studies, Universityof Wisconsin, Madison, WI 53726. Robert J. Scholes works at the CSIR Divi-sion of Water, Environment and Forest Technology, PO Box 395, Pretoria 0001,South Africa. © 2005 American Institute of Biological Sciences.A Synthesis of Information on Rapid Land-cover Change for the Period 1981–2000 ERIKA LEPERS, ERIC F. LAMBIN, ANTHONY C. JANETOS, RUTH DEFRIES, FREDERIC ACHARD,NAVIN RAMANKUTTY, AND ROBERT J. SCHOLESThis article presents a synthesis of what is known about areas of rapid land-cover change around the world over the past two decades, based ondata compiled from remote sensing and censuses, as well as expert opinion. Asia currently has the greatest concentration of areas of rapid land-cover changes, and dryland degradation in particular. The Amazon basin remains a major hotspot of tropical deforestation. Rapid cropland in-crease, often associated with large-scale deforestation, is prominent in Southeast Asia. Forest degradation in Siberia, mostly related to loggingactivities, is increasing rapidly. The southeastern United States and eastern China are experiencing rapid cropland decrease. Existing data do not support the claim that the African Sahel is a desertification hotspot. Many of the most populated and rapidly changing cities are found in the tropics.Keywords: land use, cropland, deforestation, desertification, urbanizationcover change: European Russia, South America and Africa,parts of East Asia and Southeast Asia, and the continentalUnited States and Canada, for example. There are multiple ex-amples of studies and resultant databases of rapid land-coverchange and ecosystem disturbances in important regions ofthe world: deforestation in the pantropical forest belt; fire fre-quency globally and regionally in South America, SouthernAfrica, and parts of Russia; and the influence of urbanizationin selected cities around the world.In addition to the scientific needs for a systematic docu-mentation of changes in land cover over the past severaldecades, there is a pressing need to understand these changesfrom the standpoint of their consequences for human welfare. The Millennium Ecosystem Assessment has been initiated to evaluate the degree to which ecosystem ser-vices, on which human societies depend, are sustainable,given the many environmental stresses they face (www.millenniumassessment.org). A wide variety of stakeholdershave identified the Millennium Ecosystem Assessment as acritical activity for understanding the current state and po-tential futures of ecosystem goods and services: individualcountries, international nongovernmental organizations,government agencies and ministries, international govern-mental organizations, and international multilateral envi-ronmental agreements, such as the Biodiversity Convention,the Desertification Convention, and the Wetlands Conven-tion. Early in its planning process, the Millennium Ecosys-tem Assessment identified the need to synthesize what isknown about areas of rapid land-cover change around theworld as critical to its ability to evaluate how the provisionof ecosystem goods and services has changed over the pastfew decades.ProcessTo address this need, a group of researchers agreed to sharedata and produce the most reliable current synthesis of doc-umented change over the period 1981–2000. The first stagein producing the synthesis included the following:• A compilation of existing global,