Managing Agricultural Water Use in a Changing Climate in China

Abstract

The United Nations predicts that over 40 % of the world's population (3.9 billion) would suffer from severe water deficiency by 2050, indicating that global water disequilibrium and deficiency will intensify, creating challenges for national and regional water supplies. With per capita water resources at a quarter of the world average level, China is one of the most water-scarce countries. Employing a single stage Stochastic Frontier Analysis, this paper studies the impact of climate change induced fluctuation in temperature and precipitation on agricultural water (AW) use efficiency in China and addresses its volatility and regional disparity over time and across region. We utilize fine-scale meteorological factors including temperature, precipitation, crop growing degree days and crop harmful degree days to proxy the changing climate condition. Our results reveal temperature-related climate change factors such as average annual temperature, crop growing degree days and crop harmful degree days demonstrate the negative impacts on AW use efficiency, and the decline in precipitation due to climate change lowers AW use efficiency. More importantly, we find that when the information on climate damage is provided to farmers, the negative effect of climate change on AW use efficiency can be alleviated. Furthermore, we conclude that the North China Plain, Southwest and Northeast regions with shortages of water endowment have the best AW use efficiency, followed by the Yangtze River Basin and the Northwest region. The South Coast region with ample water sources has the poorest performance. We therefore conclude that AW use efficiency in China is affected by climate change, with heterogeneous impacts across regions. Policy implications on risk management are drawn to enable better adaptation to climate change in agricultural water use.