Following the publication of the Millennium Ecosystem Assessment in 2005, a new conceptual framework was introduced for analysing social-ecological systems. The Assessment also revealed significant gaps in current scientific knowledge of the links between ecosystem services and human wellbeing.
In 2007, the International Council for Science (ICSU), in partnership with the United Nations Educational, Scientific and Cultural Organizations (UNESCO) and the United Nations University (UNU), established an ad hoc expert group to assess the knowledge gaps identified in the Millennium Assessment and how they might best be addressed by the scientific community.
This expert group published its report on Ecosystem Change and Human Well-being in December 2008.The report included a recommendation for establishing a new 10-year research program, Programme on Ecosystem Change and Society (PECS), to foster coordinated research for understanding the dynamic relationship between humans and ecosystems. This program is jointly sponsored by ICSU and UNESCO and complements the four other ICSU sponsored global environmental change programs and the Earth Systems Science Partnership.