Estimating the world's potentially available cropland using a bottom-up approach

Previous estimates of the land area available for future cropland expansion relied on global-scale climate, soil and terrain data. They did not include a range of constraints and tradeoffs associated with land conversion. As a result, estimates of the global land reserve have been high. Here we adjust these estimates for the aforementioned constraints and tradeoffs. We define potentially available cropland as the moderately to highly productive land that could be used in the coming years for rainfed farming, with low to moderate capital investments, and that is not under intact mature forests, legally protected, or already intensively managed. This productive land is underutilized rather than unused as it has ecological or social functions. We also define potentially available cropland that accounts for trade-offs between gains in agricultural production and losses in ecosystem and social services from intensified agriculture, to include only the potentially available cropland that would entail low ecological and social costs with conversion to cropland. In contrast to previous studies, we adopt a “bottom-up” approach by analyzing detailed, fine scale observations with expert knowledge for six countries or regions that are often assumed to include most of potentially available cropland. We conclude first that there is substantially less potential additional cropland than is generally assumed once constraints and trade offs are taken into account, and secondly that converting land is always associated with significant social and ecological costs. Future expansion of agricultural production will encounter a complex landscape of competing demands and tradeoffs.Fil: Lambin, E. F.. Université Catholique de Louvain. Earth and Life Institute. Georges Lemaître Centre for Earth and Climate Research; Bélgica. University Of Stanford; Estados UnidosFil: Gibbs, H. K.. University Of Wisconsin; Estados UnidosFil: Ferreira, L.. Universidade Federal de Goias; BrasilFil: Grau, Hector Ricardo. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Ecología Regional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán; ArgentinaFil: Mayaux, P.. European Commission. Joint Research Centre. Institute for Environment and Sustainability; ItaliaFil: Meyfroidt, P. . Université Catholique de Louvain. Earth and Life Institute. Georges Lemaître Centre for Earth and Climate Research; Bélgica. F.R.S-FNRS; BélgicaFil: Morton, D. C.. NASA Goddard Space Flight Center; Estados UnidosFil: Rudel, T. K.. Rutgers University. Departments of Human Ecology and Sociology; Estados UnidosFil: Gasparri, Nestor Ignacio. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Ecología Regional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán; ArgentinaFil: Munger, J. . University Of Wisconsin; Estados Unido