Seite - 24 - in options, Band winter 2014/2015

asia 24 options + winter 2014/2015 www.iiasa.ac.at regional focus Many developed regions in China are importing food and other water-intensive goods from water-scarce regions in the rest of the country, according to a new joint IIASA study. “This has potentially adverse impacts on water availability for the entire country,” explains IIASA and University of Maryland researcher Laixang Sun, a study co-author. Researchers used the concept of “virtual water,” an economic concept used to track how water is traded through agricultural products and other goods that use water in production. As Sun points out: “It takes about 1,600 m3 of actual water to produce one tonne of wheat. By importing a tonne of wheat instead of producing it domestically, a region can save most of that water.” In China, ample water in the wealthier southern region contrasts with scarce water in most northern provinces. When rich provinces such as Shanghai and Beijing import water-intensive goods from less-developed provinces, this exacerbates the problem of water scarcity in those other regions. In  addition, the production of international exports in China’s top exporting regions also draws on water resources in the water-scarce northern provinces. This study, Sun says, lays the groundwork for smarter water resource management. Recognizing the problem of water scarcity, China has launched a multi-billion dollar water transfer project to divert water from the south to the north of the country. But, replacing imports from the north with goods produced in the south could be a more efficient solution to the problem, researchers suggest. JO Further info Feng K, Hubacek K, Pfister S, Yu Y, Sun L (2014). Virtual scarce water in China. Environmental Science & Technology 48(14):7704–7713 [doi:10.1021/es500502q]. Laixiang Sun sun@iiasa.ac.at Crop yield growth for many key food crops has stagnated in much of the world since the end of the last century, but the reasons for this are unclear. In a new joint study, IIASA researchers used process-based analysis to examine the role of different drivers (climate change, use of chemical fertilizer, change in location of rice cultivation areas, and changes in crop varieties and management) in explaining rice yield development in China. While China’s national rice production increased from 143 to 197 million tonnes between 1980 and 2010, yields have stagnated over the past decade. This stagnation jeopardizes the 20% increase in production required by 2020 to feed China’s growing population. Climate change is not a factor that has impeded rice yield growth, the study suggests. Rather, yield stagnation is due to a decreasing relative contribution of fertilizer that is not being compensated for by improved varieties and management. Findings show, however, that adapting to climate change may actually contribute to yield growth by facilitating the relocation of rice-growing areas and the adoption of improved rice management. “Our crop model simulations show that national rice yield could increase by 20–50% through the introduction of climate smart rice varieties, changing sowing dates, and improving management techniques,” IIASA’s Wei Xiong points out. “Transforming agriculture to be climate-smart is one of the solutions for enhancing food supply in China, given the decreasing efficiency of chemical fertilizers, shrinking arable land, rising environmental concerns, and increasing food demand.” JO Further info Xiong W, van der Velde M, Holman IP, Balkovic J, Lin E, Skalsky R, Porter C, Jones J, Khabarov N, Obersteiner M (2014). Can climate-smart agriculture reverse recent slowing of rice yield growth in China? Agriculture, Ecosystems & Environment 196:125–136 [doi:10.1016/j.agee.2014.06.014]. Wei Xiong xiong@iiasa.ac.at China’s richest provinces worsen scarcity among water-poor regions Climate-smart farming needed to reverse crop yield stagnation