Understanding Future Projections

The document details the technical framework of Aqueduct's future projections, which utilize the HYPFLOWSCI6 dataset and five General Circulation Models (GCMs) to estimate water supply, use, stress, depletion, and variability. It describes three socioeconomic and climate scenarios (SSP1-RCP2.6, SSP3-RCP7.0, and SSP5-RCP8.5) with temperature projections ranging from 1.3°C to 5.7°C by 2100. The guide emphasizes that these scenarios represent different development pathways rather than simple best- or worst-case outcomes, noting that higher economic activity in optimistic scenarios can actually increase water stress. Technical processing includes spatial aggregation at the HydroBASINS Level 6 sub-basin level and temporal aggregation using 10-year trailing moving averages for the years 2030, 2050, and 2080. Limitations are noted regarding irrigation data (projected only to 2050) and livestock water demand (held constant after 2014).

• Aqueduct's projections are based on the HYPFLOWSCI6 dataset and utilize five General Circulation Models (GFDL-ESM4, IPSL-CM6A-LR, MPI-ESM1-2-HR, MRI-ESM2-0, and UKESM1-0-LL) to account for climate modeling uncertainties, displaying the median of these models as the central estimate.
• The tool employs three CMIP6 scenarios with varying temperature projections by 2100: the optimistic SSP1-RCP2.6 (1.3°C to 2.4°C), the business-as-usual SSP3-RCP7.0 (2.8°C to 4.6°C), and the pessimistic SSP5-RCP8.5 (3.3°C to 5.7°C).
• Scenarios should be interpreted as policy and development pathways; for instance, the optimistic scenario may result in higher water stress than the pessimistic one because it assumes increased economic activity and development leading to higher water demand.
• Data is spatially aggregated at the HydroBASINS Level 6 sub-basin level and temporally aggregated using a 10-year trailing moving average and Theil-Sen regression for 30-year trends centered on 2030, 2050, and 2080.
• The projections have specific data limitations: crop extent data for irrigation is only projected to 2050, and livestock water demand data has remained constant since 2014, which may lead to underestimations of future demand.

APA

World Resources Institute (n.d.). Understanding Future Projections. https://www.wri.org/aqueduct/help-center/understanding-future-projections

Chicago

World Resources Institute. Understanding Future Projections. n.d. https://www.wri.org/aqueduct/help-center/understanding-future-projections.

Wikipedia

{{cite report |author=World Resources Institute |title=Understanding Future Projections |url=https://www.wri.org/aqueduct/help-center/understanding-future-projections |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{worldresourcesinstitutendunderstanding, author = {{World Resources Institute}}, title = {{Understanding Future Projections}}, institution = {World Resources Institute}, url = {https://www.wri.org/aqueduct/help-center/understanding-future-projections}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }