title: People on the land: changes in global population and croplands during the 20th century.
abstract: This study reviews the major changes in global distribution of croplands during the 20th century. During the 20th century, the cropland base diminished greatly (from approximately 0.75 ha person-1 in 1900 to approximately 0.35 ha person-1 in 1990). This loss of croplands was not globally uniform: more than half the world's population, living in developing nations, lost nearly two-thirds of their per capita cropland base. The distribution of croplands has become increasingly skewed--in 1990, 80% of the population lived off less than 0.35 ha person-1. While agricultural yields have generally increased, they have barely kept pace with population growth in developing nations. Overall, the global food production system is becoming increasingly vulnerable to regional disruptions because of our increasing reliance on expensive technological options to increase agricultural production, or on global food trade.
authors.affiliation: Center for Sustainability and the Global Environment (SAGE), Institute for Environmental Studies, University of Wisconsin, 1225 West Dayton Street, Madison, Wisconsin 53706, USA. nramanku@facstaff.wisc.edu
authors.forename: Navin
authors.initials: N
authors.lastname: Ramankutty
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Foley
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Olejniczak
mesh_terms: D000383:Agriculture / Q000266:history / Q000639:trends*; D003247:Conservation of Natural Resources / Q000266:history / Q000639:trends; D003906:Developing Countries; D005502:Food / Q000266:history*; D014943:Global Health; D049673:History, 20th Century; D006801:Humans; D011157:Population Dynamics