Beschreibung:
This paper reviews main approaches to estimate the costs of REDD, with a focus on the opportunity costs. These can be classified into local-empirical, global-empirical and global simulation models. In local-empirical models, per-area opportunity cost estimates are derived from detailed studies (surveys) and carbon density estimates both specific to the particular area studied. Global-empirical models use local-empirical estimates, aggregate these to global per-area costs of reducing deforestation, and use uniform values of carbon density (ton/ha) to obtain a single, global estimate of opportunity costs ($/tCO2eq). Global partial equilibrium models simulate the dynamics of the world economy to estimate supply of REDD services (or avoided deforestation), represented in supply curves. One striking observation is that the cost of REDD differs substantially across model approaches: global simulation models yield far higher REDD prices than empirical models, including the Stern estimate. The 'true' cost estimate is most likely to lie somewhere in between the values provided by the local-empirical models on the one hand (lower end) and global simulation models on the other (higher end).