Purely theoretical or conceptual models, e.g. ISIS (Grossmann, Magaard and von Storch, 2003), NeDym (Hallegatte, Hourcade and Dumas, 2007) and the unnamed partial equilibrium model presented in Lecocq and Shalizi (2007a), are not included. The model must have been in active development since the review by Tol and Fankhauser (1998). Inactive models (e.g. CONNECTICUT, SLICE, CETA, CSERGE, MARIA, PEF, PGCAM, DIAM, AS/ExM, FARM, TARGETS, HCRA, PGCAM) are not included to avoid duplication with Tol and Fankhauser (ibid.). In addition, variants of existing models are only included if the representation of impacts and/or adaptation differs from the earlier model.