Monitoring global land-use efficiency in the context of the UN 2030 Agenda for Sustainable Development

Tracking progress toward the Sustainable Development Goals (SDGs) requires monitoring of various social-ecological indicators over space and time, including the ratio of land consumption rate to population growth rate (LCRPGR), an indicator of land-use efficiency (SDG 11.3.1). In this study, we analyzed state-of-the-art Earth observation data (1975–2015) to address three key questions. First, how has the LCRPGR varied over space and time? Second, how is built-up expansion related to population increase across regions? Third, what are some important issues related to the SDGs' land-use efficiency concept? We found that the “Europe and Northern America” SDG region was the least efficient region, having the highest LCRPGR in 1975–2000 and 2000–2015, but the “Eastern and South-Eastern Asia” SDG region is catching up. The World Bank's “high income” region and the United Nations' “very high human development” region were the least efficient regions in 1975–2000, but their places were respectively taken over by the “upper middle income” and “high human development” regions in 2000–2015. Although land consumption rate and population growth rate were positively and significantly correlated at the global level, this was not always the case across regions, indicating that land consumption was not always proportionate to population increase. We identified the non-inclusion of changes in in situ natural capital and the external impacts of cities and urban regions as among the important limitations of the SDGs' land-use efficiency concept. This can be considered in its future reconceptualization.