Virtual versus real water transfers within China.

Area of Science:

• Hydrology
• Agricultural Economics
• Environmental Science

Background:

• North China faces critical water scarcity, with over 40% of renewable water resources consumed.
• Agriculture in North China uses water to produce food for export to the water-rich South China, creating a virtual water flow.
• The South-North Water Transfer Project aims to alleviate water scarcity in the north.

Purpose of the Study:

• To quantify virtual water flows between North and South China.
• To contextualize these flows within regional water availability.
• To provide a quantitative basis for water resource management and policy.

Main Methods:

• Review of existing research on water use and food production in China.
• Calculation of virtual water export from North China to South China based on agricultural production and trade data.
• Comparison of virtual water flows with the planned capacity of the South-North Water Transfer Project.

Main Results:

• North China annually exports approximately 52 billion m³ of virtual water to South China.
• This virtual water export is a significant contributor to North China's water scarcity.
• The volume of virtual water exported exceeds the maximum proposed capacity of the South-North Water Transfer Project.

Conclusions:

• Virtual water trade represents a substantial, unaddressed water management challenge in China.
• Relying on large-scale water transfer projects may not be sufficient without addressing virtual water flows.
• Integrated water resource management strategies are needed to balance regional water availability and food security.