Recalculating Australian water scarcity characterisation factors using the AWARE method

Quantifying the impacts of water consumption on available water resources forms one of the core indicators of many life cycle assessments (LCAs). Methods for measuring this impact have been under development for over a decade, with the Available Water Remaining (AWARE) method being the current consensus approach. Available characterisation factors rely on global databases, which are built from potentially inappropriate information. This analysis aims to develop AWARE factors specific to Australian basins using the most recent meteorological data and water consumption statistics available. Australian cotton cropping is used as a case study in the application of the newly developed characterisation factors, and a cotton-specific characterisation factor is developed. The analysis involved the compilation of meteorological data quantifying water run-off and statistical data on domestic, industrial and agricultural water consumption. A geographical information system (GIS) software was used to map the information at the Australian basin level. The information was used to develop a set of monthly and annual characterisation factors for each basin and at the country level, using the AWARE method. All underpinning information is available in a public repository. A cotton-specific AWARE factor was calculated based on land cropped and average irrigation requirements over the past 10 years. Comparing the data collected for this analysis with the data underpinning the current AWARE factors revealed some significant disparities. Using up-to-date statistics suggests that irrigation water requirements are 72% lower than the value currently used in AWARE, and that the characterisation factor for Australia should be up to 35% lower than currently reported. Basin definition was reviewed to align with the Life Cycle Inventory work conducted in Australia as part of AusLCI, so that characterisation factors correspond to the elementary flows defined in the Australian database of inventories. The new breakdown provides more granularity in the Murray-Darling division, where two-thirds of Australian irrigation water is consumed. Using the updated data to develop a factor for cotton shows a 20% reduction against using the current factors. The use of up-to-date water availability and consumption data for Australia would increase the robustness of the current AWARE impact assessment method for the region. All collected information was compiled to be easily updated for future iteration. The factors could be integrated in the global database of AWARE factors, though there may be inherent complexities in this process due to the variations in the geographical definitions of basins.