The first set of population projections following the Shared Socioeconomic Pathways (SSPs) was developed in 2013, and was documented in Oxford University Press book "World Population and Human Capital in the Twenty-First Century"  edited by Wolfgang Lutz, William Butz and Samir KC (WIC2013). These projections have found widespread use within the environmental and climate change community, among others. In 2018, an SSPs update was generated in collaboration with the European Commission Joint Research Centre (report) but not integrated into the SSP database (WIC2018). In 2021, the SSP community requested an update of the human core of the SSPs. This updated version is based on 2020 as the reference year, with adjustments to certain short-term assumptions extending to 2030. Consequently, the assumptions' trend component is grounded in recent observed changes.

The modeling approaches for fertility, mortality, and educational attainment have been revised. Notably, there are updates to education-specific fertility rates with new estimates. Education-specific mortality has been made specific to countries and regions. Additionally, this version introduces explicit education-specific migration differentials. The updates are documented in a working paper by KC et al. (2024). The paper presents a comparison between the methodology used for developing the global population and education projections under the five SSPs and the previous method. Furthermore, a brief analysis is conducted on the primary results regarding population size and composition, with comparisons made to earlier projections and other organizations, including the United Nations Population Division.

Overall, and according to SSP2, which is the middle of the road scenario, the world would peak in 2080 at 10.13 billion and slowly decline after that to reach 9.88 billion in 2100. Compared to the previous exercises, the world population would peak later and at higher level of total population. WIC2018 had its peak happening in 2070 at 9.7 billion, with the world population at the end of the century at 9.3 billion. WIC2013 again projected lower population growth, peaking at 9.4 billion in 2070 and declining to 8.9 billion by 2100.

Data are available for 200 countries, by age, sex and education levels according to 7 scenarios: SSP1 to 5 to and SSP2 combined with zero migration and double migration.

The updated data and graphics are available in the Wittgenstein Centre Data Explorer at this link https://dataexplorer.wittgensteincentre.org/wcde-v3/  (beta version) and in Zenodo (v.13) https://zenodo.org/records/10618931

For more information, please contact Samir KC or Anne Goujon.


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