The blue, green and grey water footprint of rice from both a production and consumption perspective

The aim of this report is to make a global assessment of the green, blue and grey water footprint of rice, using a higher spatial resolution than earlier studies and applying local data on actual irrigation. Evapotranspiration from rice fields is calculated with the CROPWAT model; the distinction between green and blue water evapotranspiration is based on data on precipitation and irrigation. Water pollution from N-fertilisers is estimated based on application rates. The calculated green, blue and grey water footprints of paddy rice are converted into estimations of the green, blue and grey water footprints of derived rice products on the basis of product and value fractions. International virtual water flows related to trade in rice products are estimated by multiplying trade volumes by their respective water footprints in the exporting countries. We take both a production and a consumption perspective. Per nation, the total water footprint of rice production is estimated by aggregating the water footprints per production region. Next, for each nation, the water footprint of rice consumption is estimated by looking in which regions of the world the rice that is consumed in that nation is produced. The water footprint of rice consumption in a nation is calculated by aggregating the water footprints in the regions where the rice consumed in a nation is grown. For rice importing countries, the water footprint related to rice consumption is thus partly (or fully) outside the country itself.