Downscaling Global Spatial Population Projections from 1/8-degree to 1-km Grid Cells

Current SSP spatial population projections were modeled at 1/8-degree grid cells. For studies requiring data with a finer spatial resolution, this technical note presents a simple approach downscaling the 1/8-degree spatial population projections to 1-km grid cells, using a 1-km ancillary map showing total population counts in 2000.

The general spatial patterns shown by the resulting 1-km population projections are consistent with the original 1/8-degree projections. However, some spatial characteristics of both the 1/8-degree spatial population projections and the 1-km ancillary map propagated into the 1-km population projections as subtle spatial artifacts. The magnitudes of these artifacts vary across world regions, population types, and SSPs, and their potential effects on subsequent analyses should be evaluated case by case, considering what numerical and spatial precisions/details are necessary for those analyses.