August 2014: The International Water Management Institute (IWMI) has released a report, titled “Global Water Demand Projections (WDPs): Past, Present and Future,” which found that pre-1990 WDPs over-predicted water use by up to 130%, while current WDP models are prone to underestimation, particularly at the country and sector scale.

The report by Upali Amarasinghe and Vladimir Smakhtin, IWMI, examines data and sources for WDPs, pre-1990 and post-1990 global WDP results, sectoral WDPs for water-use, domestic use, industry and agriculture, and country-level WDPs. The study finds that post-1990 WDPs lack sensitivity analysis, noting that future WDP studies should identify drivers at the country level and assess how they affect water demand projections, in order to make WDPs useful for local-level planning.

The study does emphasize that the post-1990 WDPs are a significant improvement over pre-1990 WDPs and that the study of previous WDPs offers many lessons for the further improvement of WDPs. In conclusion, the study presents eight lessons for WDP studies, stressing that norms of per capita water use should not be held constant across countries and sectors. IWMI is a part of the CGIAR Consortium. [Publication: Global Water Demand Projections: Past, Present and Future] [IWMI Press Release]