Source: CO2 Science
Kummu, M., Ward, P.J., de Moel, H. and Varis, O. 2010. Is physical water scarcity a new phenomenon? Global assessment of water shortage over the last two millennia. Environmental Research Letters 5: 10.1088/1748-9326/5/3/034006.
The authors write that “due to the rapidly increasing population and water use per capita in many areas of the world, around one third of the world’s population currently lives under physical water scarcity (e.g. Vorosmarty et al., 2000; Alcamo et al., 2003; Oki and Kanae, 2006).” But they state that despite the large number of water scarcity studies that have been conducted over the years, “no global assessment is available of how this trend has evolved over the past several centuries to millennia.”
What was done
To fill this gaping void, Kummu et al. conducted a study that covered the period of time from AD 0 to 2005. This analysis was carried out for ten different time slices, defined as those times at which the human population of the globe was approximately double the population of the previous time slice. Global population data for these analyses were derived from the 5′ latitude x 5′ longitude-resolution global HYDE dataset of Klein Goldewijk (2005) and Klein Goldewijk et al. (2010), while evaluation of water resources availability over the same period was based on monthly temperature and precipitation output from the climate model ECBilt-CLIO-VECODE, as calculated by Renssen et al. (2005). (more…)