Peter is Director of the Land and Resources Rights (LRR) initiative. LRR seeks to strengthen land tenure and natural resource rights of rural people and communities by: 1) conducting research and generating new knowledge on critical property rights issues; 2) developing information platforms, including an online platform to document community rights; 3) participating in and contributing to policy and legislative reform processes; and 4) building the capacity of civil society organizations and other actors. Peter is also an Adjunct Professor at the School of International Advanced Studies, Johns Hopkins University.

For more than 25 years, Peter has worked on a range of environmental governance matters, particularly environment/democracy and environment/human rights links. He has conducted research and written on community-based natural resource management, environmental decentralization, environmental advocacy, and other environmental accountability matters. Peter has undertaken long-term field research in a number of African countries, including in Sierra Leone as a Fulbright Scholar, where he conducted research on household variability in agricultural strategies and practices; and, in Rwanda as Director of the Karisoke Mountain Gorilla Research Center, where in the 1970s he studied the behavior of mountain gorillas. Peter has also held a range of research and teaching positions at the University of California campuses at Santa Cruz and Davis.