Impact of Climate and Land-Use Changes on Water Security for Agriculture in Northern China.pdf

Journal of Integrative Agriculture 2012, 11(1): 144-150 January 2012 ? 2012, CAAS. All rights reserved. Published by Elsevier Ltd. RESEARCH ARTICLE Impact of Climate and Land-Use Changes on Water Security for Agriculture in Northern China QIU Guo-yu1, YIN Jin3 and Shu Geng1, 2 1 Key Laboratory for Urban Habitat Environment Science and Technology, School of Environment and Energy, Shenzhen Graduate School of Peking University, Shenzhen 518055, P.R.China 2 Department of Plant Sciences, University of California, Davis, CA 95616, USA 3 China Institute of Water Resources and Hydropower Research, Beijing 100038, P.R.China Abstract North China is the most important food basket of China, where the majority of wheat and corn are produced. Most crops grown in North China are irrigated, thus water security is food security. Since the 1980s, drying has been frequently observed, as shown by a reduction in precipitation, cutoff in riverflow, and shrinkage of lakes. This increase in drying cannot be explained by climate change alone. We propose that intensive land-use in this area in recent decades has had a significant impact. The objectives of the study are to develop a quantitative model of the concurrent processes of climate change and land-use in North China, and to estimate the relative contributions of each on the observed drying. We integrated relevant socioeconomic data, land-use data, and climate data in the model, and carried out a detailed multi- temporal (decade, year, day) analysis. Results showed that land-use has greatly changed since 1999. This change is mainly associated with an extremely important 1999 national policy of “returning farmland and grazing land to forest and grassland”. We found an interesting interaction between climate change and land use policy on riverflow, runoff, and evapotranspiration. During 1970s and 1980s, climate change explained more than 80%, while the land-use change explained only 10% of the riverflow change. The relative