One of the major challenges that mankind faces is the solution of environmental problems. The implementation of any solution to environmental problems critically depends on human decision making. Research within this theme focuses on environmental decisions that involve uncertainty, with consequences that are realized at different points in time, and which involve conflicting goals (consideration of short- vs. long-term outcomes, individual vs. collective outcomes, and economic, normative and hedonic consequences). Since many environmental decisions are made by groups such as households, and within organizations, we do not just consider individual decision makers, but also investigate group-level processes as determinants of environmental decisions. This research takes place in close collaboration with the Center for Research on Environmental Decisions in New York (http://cred.columbia.edu) and within the framework of the EU funded Climate KIC initiative (see http://off4firms.com/).