Global Change and Food Production

It is thought that an increase in cereal production will eventually reach to a saturation point due to the fact that the area of global arable land has been almost unchanged since 1960. However, it is predicted that the demand for cereals will increase as the global population increases. It would be necessary for Japan to constantly monitor food production both in Japan and foreign countries and to secure necessary food supplies. The aim of this study is to predict the change in area and productivity of cereal cultivation that could be caused by global warming for a 50-100 year period in order to take measures to secure future food supplies. For prediction of global changes in the planted area and cereal production in longterm view caused by global warming over a 50-100 year period, we propose a method for the identification of suitable/potential regions for major cereal cultivation using satellite remote sensing data, weather (atmospheric temperature and precipitation) data and soil data. This method detects agricultural land-use locations using satellite remote sensing data, and then extracts suitable/potential regions for major cereal cultivation which meet the required conditions, i.e. the soil property, the temperature requirement and the moisture requirement. We applied this method to predict how the area of suitable/potential regions for major cereal cultivation globally would change under conditions of double the current CO₂ concentration. We estimated the present area of suitable regions for major cereal cultivation to be 515 Mha (Million ha). Under conditions of double the current CO₂ concentration, it was estimated that the area of suitable regions would be 279 Mha which represents a decrease of 46%. We estimated the present area of potential regions for major cereal cultivation to be 1, 333 Mha. We predicted that the area of potential regions under conditions of double the current CO₂ concentration would be 1, 378 Mha, representing an increase of 3% over that of the area of present potential regions for major cereal cultivation. Using above results and the NPP (Net Primary Productivity), change in cereal production was estimated. It was predicted that the total NPP in the top 6 countries of cereal production would increase 70% caused by global warming. According to the prediction of change in NPP, it is unlikely that global warming results in the food shortage in the globe.