An average Indian uses less than half the amount of water consumed by an average American, but India is the world’s largest net virtual water exporter, using more domestic water resources for export products than any other country, says a study.
India’s per capita water consumption is 1,089,000 litres per year, while the average US consumer uses 2,842,000 litres, but trade leaves India with a net virtual water export of 95,000 million cubic metres, according to a new analysis on water use patterns.
A nation’s virtual water export is a measure of its exports of water-intensive products such as farm produce — everything from cotton to mangoes. The analysis of global water use indicates that 90 per cent of India’s gross virtual water exports relate to food products.
“The exports bring in foreign currency, which is good, but much of the export flows are not sustainable because the water used for the exports is exploited in an unsustainable way,” said Arjen Hoekstra, professor of water management at the University of Twente, and lead author of the study. “The benefits are more with the countries that import these commodities from India than with local communities in India that suffer from the misuse of water,” Hoekstra told The Telegraph.
Hoekstra and his colleague Mesfin Mekonnen estimated average water consumption in each country and analysed how different products and trade in products influence water flow. Their findings were published on Monday in the Proceedings of the National Academy of Sciences.
Argentina is the world’s second largest net virtual water exporter, its trade accounting for 92,000 million cubic metres of virtual water exports. The US is the third largest with a virtual water export of 79,000 million cubic metres, their study has shown. The analysis, which examined water patterns between 1996 and 2005, showed that Japan is the world’s largest net virtual water importer.
Water use patterns, Hoekstra said, also point to large virtual water flows within India, mainly from water-scarce regions of the northwestern states of Haryana and Punjab to wetter eastern Indian states such as Bihar. “From a water point of view, it would make sense to make Bihar more self-sufficient so that it doesn’t need to import from drier states,” said Hoekstra.
An independent study by hydrologist Sharad Jain at the Indian Institute of Technology, Roorkee, last year had also found a similar virtual water flow from the water-deficit states in northwestern India towards relatively wetter regions of eastern India.
Jain said the implications of virtual water flows measured so far are still unclear. “Almost any product, whether a cotton shirt or computer hardware, can be assigned a water tag,” said Jain. Calculations of virtual water flows will tend to be extremely complex, he said.