North Korea is a food-deficit nation in which climate change could have a significant impact on drought. We analyzed drought characteristics in the Hwanghae Plain, North Korea using both the multiple timescales of the standardized precipitation index (SPI) and the standardized precipitation evapotranspiration index (SPEI) from 1981 to 2100. The probability of non-exceedance for a one-month SPEI below −1.0 was only 1.1% in the spring season of 1995 but increased to 24.4% in 2085. The SPEI for a ten-year return period varied from −0.6 to −0.9 in 1995 and decreased to −1.18 in 2025. The results indicate that severe drought is more likely to occur in future as a result of climate change. The seasonal drought conditions were also significantly influenced by climate change. The largest decrease in the SPEI occurred in late spring and early summer, both of which are important for rice growth. Drought characteristics include severity, duration, and intensity. Therefore, we applied the time series of SPIs and SPEIs to the runs theory and found that the drought intensity identified by one-month SPEIs in 1995 was at a level of 1.21, which reached 1.39 in 2085, implying that climate change will intensify drought in the future.

Geographic Information Systems (GIS) have been widely used for spatial data manipulation for hydrologic model operations and as a supporting tool to develop spatial decision support systems (SDSS). Information technologies, including GIS and the Internet, have provided opportunities to overcome many of the limitations of computer-based models in terms of data preparation and visualisation, and provide the possibility to create integrated SDSS. This paper examines the relationship between changes in GIS technology and watershed management SDSS. It also describes a conceptual web-based SDSS framework in terms of system components and data flow. A prototype watershed management web-based SDSS that utilises the conceptual framework is examined (URL: http://pasture.ecn.purdue.edu/~watergen/owls). The SDSS uses web-GIS for watershed delineation, map interfaces and data preparation routines, a hydrologic model for hydrologic/water quality impact analysis and web communication programs for Internet-based system operation. The web-based SDSS can be helpful for watershed management decision-makers and interested stakeholders. The watershed management SDSS also provides insight into the role of GIS and information technologies in creating readily accessible and useable SDSS capabilities.

The aim of this study is to assess the impact of rice-based food security on water, energy, land, and CO₂ emissions from a holistic point of view using the Nexus approach, which analyzes tradeoffs between water, energy, and food management. In Japan, both rice consumption and the area harvested for rice have decreased. Maintaining a high self-sufficiency ratio (SSR) in rice production is an important aspect of food security in Japan, impacting the management of key resources, such as water, energy, and land. This study has, therefore, assessed the impact of various SSRs on rice production, focusing on consumption and land-use trends. First, the rice production SSR is predicted to drop to 87% by 2025 within the logarithmic trend of rice consumption and the polynomial trend line of the harvested area of rice. This reflects the fact that rice production is expected to decline more steeply than consumption between 2016 and 2025. Second, this study sets the SSRs for rice in 2025 between 80% and 100%, reflecting a range of low-to-high food security levels. In comparison with the 2016 baseline, about 0.70 $\times {10}^6$ additional tons of rice will be produced. Achieving a rice production SSR of 100% will require 10,195 $\times {10}^6$ m³ more of water and 23.31 $\times {10}^6$ GJ more of energy. Furthermore, an additional 283,000 tons of CO₂ will be emitted in 2025, as more energy is used. By contrast, an 80% rice production SSR scenario would save 1482 $\times {10}^6$ m³ of water and 3.39 $\times {10}^6$ GJ of energy, as well as making a 398,000-ton reduction in CO₂ emissions in 2015. A lower SSR would have a positive impact on resource management but a negative impact on food security. It would also reduce the income and economic status of farmers. It is, therefore, important to consider the tradeoffs between food security and resource savings in order to achieve sustainable water, energy, food, and land management in Japan.