Recently, Water Resources Research, a top journal in the field of water resources, published a paper of the research group led by Prof. Liu Junguo of School of Environmental Science and Engineering, SUSTech under the title of “Burden Shifting of Water Quantity and Quality Stress from Megacity Shanghai.”

The research group, after extensive studies, have found that developed countries are transferring carbon emissions pressure to developing countries through trade activities, but few studies have pointed out that developed regions are also shifting their water quantity and quality stress to underdeveloped regions in the form of trade. Prof. Liu Junguo’s research group, using the multi-regional input-output method and taking China’s largest city of Shanghai as an example, studied how megacities are shifting their water quantity and quality stress to other provincial administrative regions of China through virtual water trade.

The results show that in 2007 the consumption activities in Shanghai generated 11.6 billion cubic meters of fresh water consumption, 796,000 tons of COD emissions, and 16,200 tons of NH3-N emissions. And about 80 percent of water consumption and pollutant emissions from Shanghai’s consumption activities occurred in other provincial administrative regions of China. By selling products to Shanghai, some provinces consumed local water resources and polluted local water bodies to some extent. Specifically, 60 percent of Shanghai’s virtual water imports came from 13 provinces of extreme and severe water shortages, while 79 percent of COD and 75.5 percent of NH₃-N were “outsourced” to 19 provinces with water quality stress.

Fig. 1 (a) Shanghai’s net virtual water import from other provinces (b) Shanghai’s outsourcing COD from other provinces (c) Shanghai’s outsourcing NH₃-N from other provinces

The above research findings show that the burden shifting of water stress among provinces should be taken into consideration when implementing the “three red lines” (control targets for total water consumption, water use efficiency, and total pollutant emissions) of the strictest water resources management; Shanghai and the regions shifting their water stress to other regions should assume some responsibility and compensate the provinces that are relatively underdeveloped and are bearing the water resources stress; at the same time, Shanghai should actively explore ways to save water and reduce water pollution from the consumer perspective.

The above studies have received support from the National Natural Science Foundation and other fundations.

Download the article: http://onlinelibrary.wiley.com/doi/10.1002/2016WR018595/full