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In 2014, former South Korean president Park Geun-hye surprised many observers when she referred to Korean unification as a “jackpot.” Unification of North and South Korea is usually discussed in terms of its exorbitant costs—estimates range from 7 percent of South Korea’s gross domestic product for ten years to $3 trillion or more. However, Park’s pronouncement stemmed from the assumption that South Korea’s technological prowess and capital coupled with North Korea’s natural resources and labor pool would be a winning combination.

But if unification were to happen, the positive economic effects Park described would have to contend with the negative economic and social consequences of South Korea’s most transformational demographic trend—population aging. South Korea’s birth rate is now the lowest in the world, and the country’s population will continue to age, even if unification were to someday infuse some 25 million North Koreans into the equation. This demographic shift is an increasingly essential item on the balance sheet of unification’s benefits and challenges.

As others in this compendium have pointed out, South Korea’s rapidly aging population will bring on economic, social, and security challenges that an influx of young people to the country could mitigate. Estimates indicate that South Korea will need about 15.3 million more working-age immigrants by 2060 to keep the labor force from contracting, and North Korea’s working age population is estimated at around 18 million.1 A redistribution of the peninsula’s age pyramid through unification, then, would at first glance seem to present a fix to the impending crises posed by South Korea’s demographic problem.

Kathryn Botto
Kathryn Botto was a senior research analyst in the Asia Program at the Carnegie Endowment for International Peace. Her research focuses on Asian security issues, with particular emphasis on the Korean Peninsula and U.S. defense policy towards East Asia.
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But the reality is more complicated. Though unification would add millions to a united Korea’s population, the unpredictable social and economic consequences of unification and their potential impact on North Korea’s fertility rate and life expectancies could limit how readily such a population influx would help ameliorate the impact of population aging in a unified Korea.

The Demographic Profile of a Unified Korea

Projections from the Population Division of the UN Department of Economic and Social Affairs, modeled in figure 1, show that North Korea’s age structure skews younger than South Korea’s, with roughly 91 percent of the North’s population under the age of sixty-five compared to about 84 percent of South Korea’s citizenry.

Yet North Korea’s population is also aging, albeit more slowly. North Korea and South Korea are projected to average 1.86 and 1.08 births per woman, respectively, between 2020 and 2025, though the UN’s population projections have not yet accounted for significant drops in South Korea’s birth rate since 2019. (South Korea’s birth rate plummeted to 0.84 in 2020.) While both countries’ figures are below the replacement rate of 2.1 births per woman, only about 9 percent of North Korea’s population is over the age of sixty-five. By comparison, around 16 percent of South Koreas are over sixty-five—a level that North Korea is not projected to reach until about 2035. By that time, nearly 30 percent of South Koreans will be over sixty-five, while North Korea’s elderly population is not projected to approach 30 percent until 2100. Though North Korea’s birth rate is higher, these differences in population structure are also due to life expectancy. In North Korea, the average life expectancy (as of 2019) is estimated to be 68.6 years for men and 75 years for women, compared to 80.3 years for South Korean men and 86.3 years for .

Despite the relative youth of North Korea’s population, however, unification would not necessarily lead to population growth. As figure 2 shows, even if the Korean Peninsula suddenly unified into a single nation in 2020 and if both countries’ birth rates and life expectancies remained on their current trajectories, the peninsula’s total population would still stagnate by 2025 and begin to decrease consistently starting in 2035. This is because South Korea’s population is nearly twice the size of North Korea’s—its elderly population was equivalent to over 44 percent of North Korea’s total working population (ages fifteen to sixty-four) in 2020, according to UN data. Combining the two countries’ populations in this way would inject new working-age people into the total population of a unified Korea, but it also would add over 2.4 million elderly North Koreans to the tally. If the two Koreas unified tomorrow, over 13.6 percent of the population would still be over the age of sixty-five—only around 3 percentage points less than the proportion in South Korea’s current population.

The Potential Demographic Impact of Unification

The numbers in figure 2 are based on the assumption that the countries’ fertility rates and life expectancies would remain on steady trajectories after unification. In reality, however, unification would be highly likely to disrupt both factors and would probably cause population decline more quickly than figure 2 depicts. In a peaceful unification scenario, North Koreans would have better access to healthcare and means of improving their livelihoods, which over time would improve their life expectancies. For comparison’s sake, after German unification, the life expectancies of men and women in what had been East Germany rose far more rapidly than those of West Germans, increasing by a full three years between 1989 and 1999.

While it might take decades to close the gap in life expectancies between North and South Korea, fertility rates could change almost immediately, depending on how unification occurs. Immediately after German reunification, the total fertility rate among East German women began to plummet. By 1992, East Germany’s rate was 0.8 children per woman—a shockingly low number that likely would have been the lowest-ever recorded fertility rate for a country had East Germany still existed as a separate country. The rapid disruption of political and social life combined with new personal opportunities for career advancement and prosperity led East German men and women to postpone having children. By 2008, East Germany’s and West Germany’s respective total fertility rates had largely evened out. In a scenario where Kim Jong Un’s regime (or even the North Korean state) were to collapse, resulting in Korean unification, North Korea could also experience this sort of “demographic shock,” with no reliable way to predict when birth rates would recover.

Both the figure 2 scenario and the German scenario would result in the two Koreas’ populations being politically and legally unified as one nation. While such scenarios are possible, the South Korean government does not seek the kind of absorption or regime change in North Korea that would result in such an outcome. Instead, South Korean policy conceptualizes unification in terms of economic integration, open people-to-people exchanges, and peaceful coexistence—all of which could hopefully lead to eventual unification in the distant future.

A gradual transformation like this would allow room for adjustments to new conditions that were not available in the German context. But it is unclear in this gradual scenario how much responsibility the South Korean government would bear toward North Koreans in terms of social welfare costs and what South Korea would spend on infrastructure, development, and aid in North Korea. But assuming that North and South Koreans would at the very least be able to participate in one another’s economies, live in each other’s territory, and marry and have children with one another, limited assessments can be made of the social and economic implications of unifying the two Koreas in the face of aging populations.

Integrating North Koreans Into a Unified Workforce

As others in this compendium have noted, population aging is putting pressure on South Korea to reform its immigration policies and attract more migrants to augment the country’s shrinking labor force. But the country’s strong history of blood-based, ethnicity-centered national identity (danil minjok) has made the integration of multicultural immigrants difficult. In contrast, the fact that North and South Koreans share the same ethnicity is often cited by South Koreans as the most compelling reason for unification. South Koreans repeatedly have ranked ethnic ties as the number one reason for unification, followed by prevention of war. When asked which immigrant group they felt closest to in 2010, 2015, and 2020 surveys by the East Asia Institute, South Koreans consistently said they felt closer to North Korean defectors than labor migrants or marriage migrants.

North Korean defectors settling in South Korea are already subject to different laws than immigrants and other asylum seekers, and they are automatically considered South Korean citizens when they arrive in the country. Although the two Koreas have developed cultural, linguistic, and ideological differences after more than seventy-five years of division, North Koreans’ ethnic ties to South Korea could mitigate many of the obstacles to integrating into the South Korean workforce and living long term in the South that non-ethnically Korean immigrants experience.

The experiences of many North Korean defectors, however, indicate that—while acceptance may come more easily for these defectors in some ways—they still face barriers to integration. Even with their special legal status and ethnic ties, North Korean defectors have often had difficulties adjusting to South Korea and have faced discrimination. Since 1998, nearly 34,000 North Koreans have defected to South Korea. The Hana Foundation, the South Korean government’s North Korean resettlement agency, found that nearly one in five North Koreans reported experiencing discrimination over the past year due to cultural differences, prejudice against North Koreans, or lack of job skills.

Of the respondents that said they had experienced discrimination, only 22.9 percent said they had experienced job-related discrimination in the past year. But such discrimination could factor more heavily in a unified Korea, where many North Koreans would likely perform jobs in sectors that have suffered from a labor shortage due to population aging in the early stages of unification. Domestic labor shortages in South Korea in blue-collar sectors like elderly care and agriculture are one of the most compelling reasons for liberalizing South Korean immigration policy.

At the same time, perceived competition between South Koreans and immigrants in these areas is also one of the most commonly cited reasons for opposing multicultural policies. The East Asia Institute’s 2020 South Korean Identity Survey found that 42.7 percent of South Koreans agreed that “foreign laborers threaten the jobs of natives,” and less-educated South Koreans, who are commonly employed in sectors with migrant workers, were more opposed to multiculturalism than any other group. While North Koreans may fit into South Korea’s ethnic-nationalist political narrative, they are not immune from job-based or cultural discrimination. Combining the two populations would still require social and cultural adjustments and education to avoid subjecting North Koreans to many of the barriers to prosperity that many immigrants in South Korea have experienced.

Different Paths to Unification, Different Demographic Fates

Clearly, the impact unification would have on South Korea’s demographic crisis is difficult to predict. The positive and negative demographic impacts of combining the populations of the North and South would depend greatly on the circumstances of such a unification. In a peaceful and gradual unification scenario, the combination of the two Koreas’ populations could be an economic boon for both countries, filling gaps in the workforce and creating new wealth and prosperity for both North and South Koreans. But if unification were the result of conflict, instability, or regime collapse, the demographic cost could be severe. After all, millions died in the Korean War, including an estimated 20 percent of the North’s total population.

Now that South Korea’s population has declined for the first time in its history, any future unified Korea will face the challenges of population aging. A unified Korea has great potential to be economically competitive, but it will need to invest heavily in education and job training for North Koreans to thrive in a labor market where they will compete with South Koreans. This will be especially true as South Korea’s economy shifts its focus to emerging technologies to accommodate its shrinking labor force as its population ages. Closing the socioeconomic gap between North and South Koreans would take decades, and if the two countries’ citizens came to live under a single political system, vast disparities in socioeconomic statuses could manifest in a deep political divide between the two populations. This dynamic would be a daunting test for a democracy that is already growing more fractured due to changes in immigration and social policy necessitated by its aging population.

The intersection of these and other political, social, and economic transformations that unification would trigger, as well as the looming demographic challenges, could have a major impact on quality of life for both South and North Koreans. As South Korea continues to plan for the possible contingencies of unification, the challenges of population aging should be proactively considered.


1 Unless otherwise noted, the population figures and population projections mentioned in this piece are based on the author’s calculations from the following data source: “World Population Projections 2019,” UN Department of Economic and Social Affairs Population Division, 2019,