Abstract: Northeast China abounds in soybean (Glycine max L.), maize (Zea mays L.), wheat (Triticum aestivum L.), and rice (Oryza sativa L.), and is one of the most susceptive regions to climate change in the country. It has been found an increase in mean annually temperature about 0.34℃ per 10 years in recent 50 years. The probabilities of meteorological disasters, such as drought, flood and cold damages also increase with increasing of climatic variability (CV), which has caused northeast China to be one of regions with the greatest fluctuation in grain yields in China. According to IPCC, the possible increase in mean earth temperature would be 1.8-4.0℃ from now up to the end of this century. Meanwhile, the mean temperature in northeast China would be obviously higher than that of the earth. The air temperature with a doubling of CO₂ concentration (555 mmol mol^-1) in future might be 6-7℃ higher than that at present time according to the predictions of 3 GCMs. Therefore, the possible effects of changes in both climate and it variability on food production in the studied region has drawn more attentions of Chinese government and scientists. In this study, 9 scenarios of (CC+ΔCV) involving both climate change (CC) and its variability (ΔCV) were generated at 19 sites in 3 agroecological zones in northeast China using the WGEN as a tool and based on the output of the 3 General Circulation Models (GISS, GFDL, and UKMO GCMs), the local current daily weather data from 1961 to 2000 (Baseline) at each site as well as the 3 hypotheses about the increase in CV in future. Then 4 crop models, i.e., SOYGRO, CERES-Maize, CERES-Wheat, and CERES-Rice in DSSAT were selected as the effect models and their parameter modification, validation and sensitivity analyses were done using the baseline weather, statistical yield data of the 4 crops and the local typical soil data. Finally, the potential impacts of changes in both climate and its variability on the food production in the studied regions with a doubling of CO₂ concentration doubled were assessed by running the effect models under both baseline and various (CC+ΔCV) scenarios, and by making comparison between the output simulated. The results showed that the 4 effect models were available in the studied regions and can be used as a tool in climate impact study. Climate change (CC) would be favorable for soybean and rice produc-tion in the studied region, especially in the northern cold zone and eastern wet zone, but unfavorable for both maize and spring wheat, the yields simulated, particularly the maize yield, reduced significantly under all the scenarios. With increasing of CV, not only the yields reduced compared with the control (ΔCV=0), but also the yield stabilities decreased for the rainfed crops, such as soybean, maize and spring wheat. However, there was no influence for the irrigated rice.

Key words: Northeast China, Food production, Climate change, Climatic variability, Simulation model