The Program on Ecosystem Change and Society (PECS), a new initiative within the ICSU global change programs, aims to integrate research on the stewardship of social-ecological systems, the services they generate, and the relationships among natural capital, human wellbeing, livelihoods, inequality and poverty. The vision of PECS is a world where human actions have transformed to achieve sustainable stewardship of social-ecological systems. The goal of PECS is to generate the scientific and policy-relevant knowledge of social-ecological dynamics needed to enable such a shift, including mitigation of poverty. PECS is a coordinating body for diverse independently funded research projects, not a funder of research. PECS research employs a range of transdisciplinary approaches and methods, with comparative, place-based research that is international in scope at the core.