The global urbanization rate is accelerating; however, data limitations have far prevented robust estimations of either global urban expansion or its effects on terrestrial net primary productivity (NPP). Through collaborating with researchers from Sun Yat-sen University, Jiangsu Normal University, Massachusetts Institute of Technology, University of Groningen and many others, GEOG researcher, Dr. Feng co-authored a paper that showed an average of 5694 km2 per year of global urban expansion between 2000 and 2010 using a high resolution dataset of global land use/cover (Globe-Land30). The rapid urban expansion in the past decade has in turn reduced global terrestrial NPP, with a net loss of 22.4 Tg Carbon per year (Tg C year−1). Although small compared to total terrestrial NPP and fossil fuel carbon emissions worldwide, the urbanization-induced decrease in NPP offset 30% of the climate-driven increase (73.6 Tg C year−1) over the same period. The findings highlight the urgent need for global strategies to address urban expansion, enhance natural carbon sinks, and increase agricultural productivity.