Climate change and shifts in cropping systems together exacerbate China’s water scarcity

Abstract

Abstract Water shortage is regarded as the most critical constraint limiting the world’s capacity for food security. While previous studies have attributed water scarcity primarily to climate change or some natural factors (e.g. lack of fresh water), few have investigated the impacts of shifts in agricultural systems on water resources. This study quantitatively distinguished the effects of spatiotemporal changes in climatic factors (e.g. temperature and precipitation), planted area, and crop type on China’s irrigation water resources by use of logarithmic mean Divisia index. The results indicated that in the past 25 years (from 1990 to 2015), changes in planted area, crop mix, and climatic factors all led to an increase in irrigation water demand (IWD) in China. Changes in planted area had the greatest effect on IWD (+45.4 × 109 m3), followed by the climate change effect (+10.8 × 109 m3). In particular, the rapid expansion of maize and other crops in northern China in recent decades has greatly increased irrigation water consumption. It is suggested that in addition to mitigating the adverse effects of climate change, China must address its water scarcity problems by appropriately controlling the scale of some water-intensive crops. These strategies will be essential for adapting agricultural production to future climate change while ensuring food security and water sustainability.