1. Energy and Resources Group, UC Berkeley, 310 Barrows Hall, Berkeley, California 94720, United States, Goldman School of Public Policy, UC Berkeley, 2607 Hearst Avenue, Berkeley, California 94720, United States, Earth Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS 90-1116, Berkeley, California 94720, United States, and Woods Institute for the Environment, Program on Food Security and the Environment, Stanford University, Stanford, California 94305, United States