Impact of climate change on water resources and adaptation strategies in the main grain production belt of the North China

Climate change, as one of the important global environmental issues, distorts the hydrologic cycle and therefore has significant implications for regional water resources. The grain production belt of the North China mainly consisting of the Yellow River Basin, Hai River Basin and Huai River Basin is the region most vulnerable to climate change in China. The major water issues in this region (including severe shortage of water resources and increasing regional flooding) have attracted significant attentions from both the central government and local communities. It is therefore critical to analyze future trends in water resources and seek for adaptive strategies to climate change in the region. Using statistical methods such as the Mann-Kendall test, variations of historical runoff recorded during the period 1950-2010 at ten key hydrometric stations on the main streams of the Yellow River, Hai River and Huai River were analyzed. Based on seven GCM projects under the three emission scenarios of RCP2.6, RCP4.5 and RCP8.5, the VIC (Variable Infiltration Capacity) model was used to simulate future water resources in these basins. Using 1961-1990 as the baseline period, changes in future water resources were analyzed for each decade. The results suggested that the recorded runoffs in the middle and lower reaches of both the Yellow River Basin and the Hai River Basin significantly decreased in the last 50 years. There was a insignificant change in the Huai River Basin and in the upper Yellow River Basin. For the Hai River Basin in particular, recorded runoff after 1980 deceased by over 50% compared to the value in 1961. While projected temperature steadily rose in the next 30-50 years, precipitation slightly increased over the period. Changes in water yields under the RCP2.6, RCP4.5 and RCP8.5 climate scenarios were estimated to change by ?1.3%, 1.0% and ?2.3%, respectively, distorting the spatial distribution of water resources in the region. Water resources in the middle Yellow River Basin increased while those in both the Hai River Basin and the Huai River Basin decreased, particularly under the RCP8.5 climate scenario. The degree of water shortage in the main grain production belt of the North China was aggravated by the simulated climate change. The core activities of adaptation to climate change included enhancement of the construction of water-saving society, the full use of non-traditional water resources and also the speeding up of the planning and implementation of water conservancy projects in the region.