Simulation Of Main Food Crops Production Under Future Climate Change Scenarios In China

The climate is changing due to the higher concentration of greenhouse gases has been concluded by climate simulations. Lost of impacts of climate change would cast to some sectors, e.g. agriculture, forestry, etc. Agriculture is a basic sector to community, especially to such a huge population country-China. Therefore, using the newest technologies relevant to climate change, to understand the impacts of climate change on Chinese agriculture, is extremely helpful to policy maker and international environmental agreements.We assessed the impacts of climate change on Chinese agriculture in regional scale using the regional simulation. The IPCC SRES greenhouse gases emission scenarios A2 and B2 were used in simulation, combining with the regional climate model - PRECIS to provide long term present and future daily weather data. Using the regional crop model and GIS technologies, the yield changes of three main crops - rice, wheat and maize were concluded in 50x50 km scale. Base on the assumption of Chinese population, economy by IPCC SRES, the food security was issued in this paper.For the site-specific of most of the process crop model, a regional crop model - RCMCA, which original from CERES series crop model, based on the theory of regional application of site-specific crop model and the regional crop parameter, soil attributes and agronomic parameters, was established in this study, the validation was done at site scale and regional scale respectively. Then using this model, average and total yield changes relative to yield at the baseline climate were simulated for 2020s, 2050s and 2080s under both IPSS SRES A2 and B2 greenhouse gases emission scenarios, the distribution of the rice planting was also estimated. Finally, with the assumption of society-economy and population issued by IPCC SRES, the food security of 2080s under A2 greenhouse gases emission scenarios was analyzed. The results were: The average temperature as well as the precipitation would increase greatly under both A2 and B2 greenhouse gases emission scenarios, the distribution of changes for temperature and precipitation are different for different regions. If the CO2 direct effect was not included in the simulation, the average and total yield of crops would decrease under all scenarios, wheat shown the highest decrease, maize shown the lowest, highest decrease occurred in 2080s, lowest in 2020s. Irrigation would offset that decrease but could not stop it. If the CO2 direct effect was included in the simulation, the impacts of climate change on crops shown both positive and negative corresponding to different scenarios. Rice yield increases under A2 emission scenario while decrease under B2, wheat yield increases under all scenarios, and yield increases for rainfed maize while decreases for irrigated maize under all scenarios. For three crops, yields decrease in main crop planting areas while increase in other areas. The food would meet the demand of the sustainable development of China in 2080 if only the climate change was taken into account in the analysis. But unless the contribution rate of technology to the agriculture kept 1% every year, the food could meet the demand of sustainable development of China in 2080 under A2 emission scenarios if the population, economy was taken into account in the analyses.