Preparing population scenarios by age, sex, and level of education for all countries as part of the global SSP effort

These communities recently agreed to refer to a common set of Shared Socioeconomic Pathways (SSPs) that describe alternative future worlds with respect to social and economic mitigation and adaptation challenges. Unlike the previous generation of scenarios, which only considered total population size in addition to GDP, this new set of scenarios provides alternative population projections by age, sex, and six levels of education for all countries in the world. In so doing, it covers the human core of the SSPs much more comprehensively.

The completion of the SSPs coincided with the finalization of the major new expert-argument based projection effort carried out by IIASA and VID in collaboration with Oxford University. More specifically, the medium scenario of these new projections, which is considered the most likely in terms of future fertility, mortality, migration, and education trends, has been set to be identical with SSP2 which reflects a “middle of the road” narrative about future trends. SSP1 envisages a rapidly developing world with more education, lower mortality, and a more rapid fertility decline in high fertility countries, whereas SSP3 assumes increasing global inequality in the context of social and economic stagnation leading to stagnant school enrollment rates and retarded demographic transition. By 2050, these two scenarios already differ greatly with respect to the resulting age and education structures. Total population size will differ by as much as 1.5 billion over the coming four decades (8.5 billion for SSP1 and 10.0 billion for SSP3).

The Wittgenstein Centre recently published a 5-year report that summarizes the achievements and work of its scientists.

Under the most likely “middle of the road” SSP2 scenario, world population is projected to increase to 9.17 billion in 2050, then peak at 9.4 billion around 2070, and reach 9.0 billion by 2100. These numbers are a little lower than those published by the UN in its 2010 Assessment, mainly because the UN assumes long-term convergence around a total fertility rate (TFR) of 2.1, while the middle of the road scenario assumes 1.75. But there are many more country-specific differences, notably for China, where this scenario also assumes lower near-term fertility than the UN does. Under the stalled development scenario SSP2 world population reaches 12.6 billion by the end of the century whereas the rapid development scenario results in a peak in around 2050 followed by a decline 6.9 billion in 2100 (i.e., lower than today’s world population).

Last edited: 03 October 2013