The Impact Of Climate Change On Production Of Multiple Food Crops In The 21st Century- An Analysis Based On Two Land Surface Models

Abstract:

Climate change presents potential risks to global food supply. To date, understanding of climate change effects on crop production remains uncertain due to (1) uncertainties in projected climate change trends and their spatial and temporal variability; (2) uncertainties in the physiological, genetic and molecular basis of crop adaptation to climate change and adaptive management practices and (3) uncertainties in current land surface models to estimate crop adaptation to climate change. We apply the process-based land surface model, the Integrated Science Assessment model (ISAM), to assess the impact of climate change on the production of row crops (corn, soybean, rice, cotton, sugarcane and wheat) at global and regional scales. The results are compared to the corresponding simulations performed with the crop model in the Community Land Model (CLM4.5). Three questions are addressed: (1) what is the impact of different climate change projections on global crop production; (2) what is the effect of crop adaptation and adaptive management practices on projected crop production; and (3) how do model differences in ISAM and CLM4.5 impact projected global crop production and adaptive management practices over the 21st century.

ISAM and CLM4.5 have been included in the Agricultural Model Intercomparison and Improvement Project (AgMIP). Both models consider the effects of temperature, light and soil water and nitrogen availability on crop photosynthesis and temperature control on crop phenology and carbon allocation. ISAM also considers the adaptation of crop phenology, carbon allocation and structures growth to drought, light stress and N stress. The effects of model differences on projected crop production are evaluated by performing the following experiments. Each model is driven with historical atmospheric forcing data (1901-2005) and projected atmospheric forcing data (2006-2100) under RCP 4.5 or RCP 8.5 from CESM CMIP5 simulations to estimate the effects of different climate change projections on crop production potential. For each set of atmospheric forcing data, crop production is simulated with and without inclusion of adaptive management practices to assess the effect of adaptation on projected crop production. The result of this study contributes to the overall objective of the AgMIP project.