LAUSR

Before transitioning to questions of sustainability, international research agendas addressing the Anthropocene focused on global environmental change, or the alterations in the structure and functioning of the earth system affected by human activity. Research focusing on terrestrial ecology recognized that projecting such changes into the future required an understanding of social-environment systems (SESs). Terrestrial ecological research, therefore, needed integration with social science research addressing the causes and projections of land uses—the purpose to which humankind employs the earth’s surface—and land cover— a principal link to the biophysical subsystem. This integration generated the Land-Use and Land-Cover (LUCC) program on which the Turner et al. (1994) Ambio article was based. Overall, this program focused on ‘‘cause-to-cover relationships’’ with the goal of informing various efforts to project forthcoming environmental changes from local to global scales. Recognizing the complexity of SESs, part of the program called for identifying large-scale cause-tocover situations (e.g., tropical deforestation or arid land degradation), developing a common research protocol, and generating systematic assessments of the situations to identify the major drivers of different land changes to improve future projections of them. Several meta-analyses of cause-to-cover change subsequently followed (e.g., Geist and Lambin 2002; Verburg et al. 2015). Systematic and analytically rich comparisons of the kind called for in the 1994 Ambio article did not, owing to funding constraints and new research questions and problems posed to the program by its parent organizations and revolving science committees. The enlarged problem-set directed to land-use and cover subsequently gave rise to the Global Land Programme (GLP; now part of Future Earth) and a new field of study recognized as land system science (Verburg et al. 2015). This science engages a large range of research integrating the social and environmental sciences with strong links to the remote sensing and geographical information sciences, and to various modeling approaches. Land system science seeks to integrate these interests through the lens of SESs to address (1) why, how, where human activity, locally to globally, affects the terrestrial surface and (2) the consequences of the impacts, especially for sustainability issues, and to assist (3) in projecting land-use and -cover changes and their consequences in the near-term future. In addition, land system science has added the urban category to its land inventory, addressing the implications of urban sustainability through land-use and -cover dynamics (e.g., Seto et al. 2012). Here we trace some of the major advances in land system science and the challenges it faces.