Intra- and extraregional cropland footprints and their implications for food security: A case study of an island region in Japan

<h2>Abstract</h2> Food production significantly impacts on land footprint, particularly cropland use. Ensuring food security requires reducing reliance on unmanageable footprints, such as extraregional land use along the supply chain. In this study, we developed a model to analyze the intra- and extraregional cropland footprints associated with final demand in a region to assess land use-related supply risks. The developed model was demonstrated on a case study of Okinawa, an island prefecture in Japan. First, we investigated temporal changes in import-induced foreign cropland use areas for both foods and nonfood products and materials. To quantify the cropland footprints, an analysis model using regional input–output tables was developed. The Herfindahl–Hirschman Index was applied to calculate the degree of dependence on foreign cropland use and identify land use-related supply disruption risks. In 2011/2015, cropland use in the United States accounted for the largest share of 24 %/19 % of the total associated cropland use area, while Okinawa and the other domestic regions in Japan accounted for 9 %/15 % and 16 %/14 %, respectively. In 2011/2015, a large part of intraregional cropland use was devoted to exporting to other domestic regions (72 %/75 %), rather than to the intraregional final demand of Okinawa (27 %/23 %). Our analysis indicates that Okinawa utilizes its land resources through the export of regional specialties, whereas the dependency on foreign cropland use indicates vulnerability in terms of food security. Particularly, both the foreign cropland use rates and concentration of land-user countries were high for certain food products including wheat, grain milling, and fruits. The identified land use-related supply disruption risks highlight the need for measures to control the reliance on extraregional land use and ensure food security.