The blue, green and grey water footprint of rice from production and consumption perspectives

The paper makes a global assessment of the green, blue and grey water footprint of rice, using a higher spatial resolution and local data on actual irrigation. The national water footprint of rice production and consumption is estimated using international trade and domestic production data. The global water footprint of rice production is 784 km3/year with an average of 1325 m3/t which is 48% green, 44% blue, and 8% grey. There is also 1025 m3/t of percolation in rice production. The ratio of green to blue water varies greatly over time and space. In India, Indonesia, Vietnam, Thailand, Myanmar and the Philippines, the green water fraction is substantially larger than the blue one, whereas in the USA and Pakistan the blue water footprint is 4 times more than the green component. The virtual water flows related to international rice trade was 31 km3/year. The consumption of rice products in the EU27 is responsible for the annual evaporation of 2279 Mm3 of water and polluted return flows of 178 Mm3 around the globe, mainly in India, Thailand, the USA and Pakistan. The water footprint of rice consumption creates relatively low stress on the water resources in India compared to that in the USA and Pakistan.