Virtual water trade and water footprint of agricultural goods: the 1961–2016 CWASI database

Abstract

Abstract. To support national and global assessments of water use in agriculture, we build a comprehensive and harmonized database of water footprint and virtual water trade (VWT) data for hundreds of agricultural goods. The water footprint, indicating the water needed for the production of a good, including rainwater and water withdrawals, is expressed as a volume per unit weight of commodity (or unit water footprint, uWF), which is here estimated at the country scale for every year in the period 1961–2016. The uWF is also differentiated, where possible, between production and supply, referring to local production only and to a mixed role of local production and import, respectively. The VWT data, representing the amount of water needed for the production of a good and virtually exchanged with the international trade, are provided for each commodity as bilateral trade matrices, between origin and destination countries, for every year in the period 1986–2016). The database, developed within the EU-funded CWASI project, improves upon earlier datasets because it takes into account the annual variability of the uWF of crops, it accounts for both produced and imported goods in the definition of the uWF and it traces goods across the international trade up to the origin of goods' production. The CWASI database is available on the Zenodo repository at https://doi.org/10.5281/zenodo.3987468 (Tamea et al., 2020) and welcomes contributions and improvements from the research community to enable analyses specifically accounting for the temporal evolution of the uWF.

Trade of Economically and Physically Scarce Virtual Water

“…The CWASI database includes data on the uWF for each crop in each country over the period 1961-2016 [38].…”

“…We aim at assessing the VW trade associated to primary crops under the lens of our composite water scarcity index. Therefore, firstly we sum the VW volumes associated to the trade of 123 primary crops exchanged by every country pair in 2016, which is the last year available in the VW trade matrix developed in the CWASI database [38] (see Data and Methods and the Supplementary Material). In our matrix we include 151 countries and 22,200 VW fluxes encompassing a total of 1.27E+12 VW cubic meters (See Supplementary Materials).…”

“…We select all the primary crops traded internationally -with the exclusion of live animalsfor a total of 123 crops (see Supplementary Table S5). We utilize the virtual water (VW) trade matrix for the year 2016, which is the last year for which data are available in the CWASI database developed by Tamea et al [38]. We sum the virtual water associated to the trade of each selected product, obtaining the total volumes of virtual water associated to primary crops exchanged by every country pair.…”