By Dr Sarah Christison, Dr Chia Liu, Dr Júlia Mikolai, Professor Hill Kulu, School of Geography and Sustainable Development, University of St Andrews, and ESRC Centre for Population Change.

Within the first month of Russia’s invasion of Ukraine, it is estimated that around ten million Ukrainians became displaced from their homes, including around 3.5 million who sought refuge in neighbouring countries. This has been described as the largest and most rapid movement of people in Europe since WWII. While the short-term impacts of the war in Ukraine are clear, the mass displacement of people is likely to have long-term implications for the country, depending on how Ukraine emerges from the conflict, and, in turn, to influence the decisions made by refugees about whether or not they will return following the war.

Since gaining independence from the Soviet Union in 1991, Ukraine’s population has been in decline, decreasing from 52 million in 1991 to around 41 million in 2021. While some of this decline can be attributed to the annexation of Crimea by Russia in 2014 and the ongoing war in the Donbas region of Ukraine, natural population change has been the primary driver of population decline since the early 90s, with deaths outnumbering births since 1993. Despite marginally positive net migration observed since the mid-2000s, low fertility levels have continued to result in population decline.

To explore the effect that Russia’s invasion of Ukraine could have on the future population of the country over the next 20 years, we conducted a series of population projections to compare a range of scenarios to levels of population change we would expect if current trends in fertility, mortality and migration were to continue in the absence of war. For these projections, four scenarios were imagined, not to predict possible outcomes of the conflict, but to illustrate how patterns of forced migration out of the country and the rate of return of refugees would impact population size and structure.

The baseline projection assumes the continuation of trends observed in 2021; the scenarios assume either 2.5 or five million refugees leaving Ukraine, and either 10% or 90% returning. While the exact demographics of the refugees is still unknown, this group is largely made up of young women and children, with men aged between 18-60 prohibited from leaving the country to reinforce military defences. We also assume that young men currently in Ukraine will later reunite with their displaced families abroad. For example, if 10% of refugees will stay abroad for a long time period, each woman will be joined by a man of the same age group. The number of military deaths were distributed among men in their 20s, while civilian deaths were shared proportionally across age and gender and informed by the latest breakdown of civilian deaths from the United Nations.

Across all scenarios, including the baseline, projections suggest that the population of Ukraine is set to further decline between 2020 and 2040. However, the scale of this decline varies depending on the number of refugees leaving Ukraine and the proportion that return. The baseline projection suggests that the population will decline by around 16% by 2040, compared to 33% in scenario 4 with five million refugees and only 10% of them returning. These projections also suggest that the conflict in Ukraine could exacerbate the country’s already ageing population, with dramatic changes in the age structure of the projected population. All scenarios considering the effect of the war show a further decline in the size of the working age population and of children, while the share of the elderly population is set to increase.

The comparison shown in the population pyramid diagram illustrates and summarises the main changes in Ukraine’s population between the baseline scenario and scenario 4. We see a declining and ageing population. Most importantly, the decline and ageing of Ukraine’s population will be pronounced, with increasing war casualties and a large refugee population staying abroad.

These projections show that the effect of the war is likely to exacerbate Ukraine’s population decline and increase the rate of population ageing over the next two decades. Should large numbers of refugees fail to return following the war due to potential undesirable political and economic factors, Ukraine’s population may decrease by up to a third as projected by the most extreme scenario set out in this analysis. In particular, these projections suggest that the working age population and the share of children are likely to decline most significantly, with adults over 60 making up an increasing proportion of the population.

These findings emphasise the importance of refugees returning to Ukraine and highlights the importance of rebuilding Ukraine following the war in such a way as to enable and attract refugees to return. This would minimise the serious demographic consequences which could be incurred as a result of the conflict.