Introducing the CRISP model to downscale future population projections

The CRISP model has been setup to disaggregate national population projections to 1km2 grid cells globally. This is done primarily to provide projections of population by degree of urbanisation for the 2025 World Urbanisation Prospects report produced by the UN. Many other applications are feasible with CRISP as well. The model estimates population and built-up area change in a three-step process. First, population and built-up area change are estimated for roughly 1000 functional areas taking into account national population projections. Second, new built-up area is allocated to grid cells considering distance to settlements, roads, water, current share of built-up area and other characteristics. Finally, population is added to newly built-up areas and more suitable locations and reduced in less suitable locations to capture internal migration (and natural population decline).