Land use representation in a global CGE model for long-term simulation: CET vs. logit functions

Land use is one of the key elements in global computable general equilibrium models for food security and agricultural assessment. Constant elasticity transformation (CET) or logit functions have been used to allocate land. CET has the advantage that it is easily handled by modeling tools. However, it does not maintain area balance, whereas logit does. This article compares both functions in future scenarios and evaluates area balance violations of land use area made by CET. We found that agricultural goods production and land use were similar with CET and logit functions. The area balance violation generated by CET was large and heterogeneous across regions, but was small for the aggregated world total. In conclusion, the logit approach was preferable to the CET approach if any scenario assumption, such as consumption preference, changed by much from the base year, or if the main focus of the study was region-specific variables rather than global aggregates.