1. Stockholm Environment InstituteOxford Office, 266 Banbury Road, Suite 193, Summertown, OX2 7DL, UK
2. School of Geography and the Environment, University of OxfordSouth Parks Road, Oxford, OX1 3QY, UK
3. Department of Geography, University of CambridgeDowning Place, Cambridge, CB2 3EN, UK
4. Department of Environmental & Geographical Science, University of Cape TownPrivate Bag, Rondebosch 7701, South Africa