Future urban land expansion and implications for global croplands

Abstract

Urban expansion often occurs on croplands. However, there is little scientific understanding of how global patterns of future urban expansion will affect the world's cultivated areas. Here, we combine spatially explicit projections of urban expansion with datasets on global croplands and crop yields. Our results show that urban expansion will result in a 1.8-2.4% loss of global croplands by 2030, with substantial regional disparities. About 80% of global cropland loss from urban expansion will take place in Asia and Africa. In both Asia and Africa, much of the cropland that will be lost is more than twice as productive as national averages. Asia will experience the highest absolute loss in cropland, whereas African countries will experience the highest percentage loss of cropland. Globally, the croplands that are likely to be lost were responsible for 3-4% of worldwide crop production in 2000. Urban expansion is expected to take place on cropland that is 1.77 times more productive than the global average. The loss of cropland is likely to be accompanied by other sustainability risks and threatens livelihoods, with diverging characteristics for different megaurban regions. Governance of urban area expansion thus emerges as a key area for securing livelihoods in the agrarian economies of the Global South.

Keywords: agricultural productivity; global land use change; livelihoods; megaurban regions; urbanization.

Fig. 1.

Maps show where projected urban expansion until 2030 is expected to result in cropland loss. Competing areas (red) hold croplands but have a high probability (>75%; medium scenario) of becoming urbanized by 2030. (A–E) Close-ups of urban area expansion hot spots. Data on urban expansion are from ref. , and data on cropland are from ref. .

Fig. 2.

Competition between croplands and urban expansion in select MURs. The maps show where projected urbanization until 2030 is expected to result in cropland loss. Competing areas (red) hold croplands but have a high probability (>75%; medium scenario) of becoming urbanized by 2030. MURs displayed are (A) Pearl River Delta, (B) Yangtze River Delta, (C) Bohai Economic Rim, (D) Tokaido Corridor, (E) Delhi National Capital Region and Jaipur, (F) Ganges-Brahmaputra Delta (Kolkata, Dhaka, and Chittagong Region), (G) Java, (H) Northeast Megalopolis, (I) Expanded Metropolitan Complex of São Paulo, (J) Greater Ibadan Lagos Accra Corridor (GILA), and (K) Greater Cairo Region. See Supporting Information for more details.