The use of crop models for international climate change impact assessment

Abstract

The methodology for an assessment of potential impacts of climate change on world crop production, including quantitative estimates of yield and water-use changes for major crops, is described. Agricultural scientists in 18 countries estimated potential changes in crop growth and water use using compatible crop models and consistent climate change scenarios. The crops modeled were wheat, rice, maize and soybean. Site-specific estimates of yield changes for the major crops modeled were aggregated to national levels for use in a world food trade model, the Basic Linked System. The study assessed the implications of climate change for world crop yields for arbitrary and GCM equilibrium and transient climate change scenarios. The climate change scenarios were tested with and without the direct physiological effects of CO2 on crop growth and water use, as reported in experimental literature. Climate change impacts on crop yields incorporating farm-level adaptation were also simulated, based on different assumptions about shifts in crop planting dates, changes in crop variety, and level of irrigation.