School of Earth and Ocean Sciences, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, UK

Department of Physics and Physical Oceanography, Center for Marine Science, University of North Carolina-Wilmington, 601 South College Road, Wilmington, NC 28403, USA

Nicholas School of the Environment, Dept. of Economics, Duke University, P.O. Box 90328, Durham, NC 27708, USA

Department of Agricultural, Environmental and Development Economics, The Ohio State University, 2120 Fyffe Road, Columbus, OH 43210, USA

Division of Earth and Ocean Sciences, Nicholas School of the Environment, Center for Nonlinear and Complex Systems, Duke University, 103 Old Chemistry Building, P.O. Box 90227, Durham, NC 27708, USA