Water scarcity conditions are expressed in this study by means of the Water Crowding Index (WCI), i.e. the annual water availability per capita (Falkenmark, 1986; 2013). Due to its ease in use and its simplicity in understanding, the WCI consists among the most often used indicators in water scarcity assessments, see for example: Falkenmark, 2013; Hoekstra et al., 2012; Kiguchi et al., 2014; Kummu et al., 2014; Oki & Kanae, 2006; Schewe et al. 2014, Veldkamp et al., 2015a, 2015b; Vorosmarty et al., 2000; Wada et al., 2011a. In line with previous studies, we used ≤1700 m3/capita per year as the threshold for moderate water scarcity conditions. Result found under severe (≤1000 m3/capita per year) and absolute (≤500 m3/capita per year) water scarcity conditions are presented in the supplementary. Population estimates per water province were derived using downscaled socio-economic scenarios from the Shared Socio-Economic pathways (Van Vuuren et al., 2007, 2011). Following Winsemius et al (in review), we used three SSP scenarios to complement the climate projections: (1) SSP1, forms with RCP2p6 the ‘Suitability’ storyline; (2) SSP3, forms with RCP6p0 the ‘Fragmented World storyline; and (3) SSP5, forms with RCP8p5 the ‘Fossil-fuel based development’ storyline. For an extensive discussion on these storylines and the associated SSP and RCP combinations we refer to Winsemius et al. (in review).
