Global 0.5-Degree Grids of Streamflow Decline Projection (RCP8.5 2050s), v1

Half a billion people already face consistent, year-round, severe water scarcity. As cities grow, demand and competition for limited clean water resources will increase, and climate-linked impacts are very likely to make these pressures worse in urban areas across the globe. While short-term peak river runoff from increasing meltwater may temporarily offset drought scarcities in some regions, long term glacial retreat will probably diminish meltwater runoff overall. Here water availability risk is identified in the database when the multi-model (two global hydrologic models; four global climate models) ensemble mean of naturalized streamflow is projected to decline by at least 10 percent in the 2050s (i.e. 2041-2070) compared to the baseline period (1980-2005). By using naturalized flows (i.e., modelled streamflow without the interference of human-made structures), it is possible to isolate the impact of climate change on water availability; representative concentration pathway 8.5 (RCP8.5) was used in all cases. This approach does not take into account water resources available in human-made reservoirs, in underground water storage, or from desalination plants; nor does it include any infrastructure for the transfer of water between river basins. 1980-2005 was chosen for the baseline as this time period aligns with publicly available climate data and captures recent climate trends. The 2050s time slice was chosen due to stakeholder interest in projected climate change impacts that could be associated with year 2050.

This database was developed along with a technical report: The Future We Don’t Want prepared for the C40 Cities Group by the Urban Climate Change Research Network (UCCRN) in 2018.

The same four global climate models (GCMs) were used in all the multi-model mean calculations (IPSL-CM5A-LR, MIROC-ESM-CHEM, GFDL-ESM2M, NorESM1-M). From the framework created by the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP Fast Track), a set of two global hydrological models (GHMs) – JULES and LPJmL – have been applied using bias-corrected forcing from the four GCMs utilized. Grid cells are 0.5 by 0.5 degrees; results reflect the projected change (%) in the multi-model mean of naturalized streamflow under RCP8.5.

Braneon, C. and C. Rosenzweig. 2021. Global 0.5-Degree Grids of Streamflow Decline Projection (RCP8.5 2050s), v1 (Preliminary Release). Palisades, NY: NASA Socioeconomic Data and Applications Center (SEDAC). http://www.ciesin.columbia.edu/data/global-grid-sf-decline-projection-2050-v1/. Accessed DAY MONTH YEAR.

This is a preliminary open data release, pending peer review of the data and associated journal articles. Following the peer review process, data curation will be completed by the NASA Socioeconomic Data and Applications Center (SEDAC) and the data will be disseminated through the SEDAC catalog.