Projection scenarios
After 2023 GeoScope.ch’s population data are United Nations projections (World Population Prospects 2024). A projection is not a forecast: it shows how things would go if births per woman, life expectancy and migration followed certain assumptions. Change the assumptions and the result changes: that is why the UN computes several scenarios.
World population in the five scenarios
In 2100
- 10.2 bnMedium
- 14.4 bnHigh (more children)
- 7.0 bnLow (fewer children)
- 18.2 bnConstant fertility
- 10.1 bnZero migration
The five scenarios
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Medium
The reference scenario, the one the site uses unless you choose another. For each country the UN estimates how births per woman and life expectancy will change, based on how they changed in other countries, and takes the most likely value; migration follows recent trends.
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High (more children)
Like the medium, but with more births per woman in every country: 0.25 more until 2028, 0.4 from 2029 and half a child (0.5) from 2034; that is why the lines show steps. Life expectancy and migration do not change.
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Low (fewer children)
Like the medium, but with fewer births per woman in every country: 0.25 fewer until 2028, 0.4 from 2029 and half a child (0.5) from 2034, with the steps. Life expectancy and migration do not change.
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Constant fertility
Births per woman stay at their 2023 level until 2100. It is not a realistic assumption: it shows how much the fertility decline expected in the medium scenario matters.
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Zero migration
Like the medium, but with no migration from 2024: nobody arrives and nobody leaves. It shows how much immigration (or emigration) matters for a country’s population.
What changes and what does not
Up to 2023 the data are estimates and are the same in every scenario. In the high, low and constant-fertility scenarios life expectancy is the same as in the medium scenario; in the zero-migration scenario births per woman are. When an indicator in the chosen scenario is the same as in the medium one, the site says so below the chart.
Uncertainty: the fan
In the line chart each country can get a fan. “Low to high” shades the space between the low and the high scenario. “95% probable” uses the UN probabilistic projections: thousands of possible futures, computed by varying births per woman, life expectancy and migration the way they varied in the past; the fan contains 95 futures out of 100. The fan is shown for countries, the world and continents, only for the indicators the UN publishes it for; for the world and continents the 95% interval is the one the UN computes for its regions.
Where you choose the scenario
The “Projection scenario” control is in the rankings, the bubble and line charts, the thematic map, the population pyramids, the Demography pages, the migration page and the country pages. The chosen scenario stays in the page address, so a shared link shows the same scenario.
Source: United Nations, Department of Economic and Social Affairs, Population Division, World Population Prospects 2024 (CC BY 3.0 IGO): projection variants and probabilistic projections. population.un.org/wpp