Japan’s Demographic Shifts and Regional Security Challenges Ahead

by Andrew Oros

Asia Pacific Bulletin, No. 523

Publisher: Washington, DC: East-West Center
Available From: August 26, 2020
Publication Date: August 26, 2020
Binding: Electronic
Pages: 2
Free Download: PDF


Andrew Oros, professor of political science and international studies at Washington College, explains that “While, Japan’s military capabilities may be said to have improved despite demographic decline, the size of its military appears to be more directly affected, and the outlook for funding the military is unclear.”


Japan is one of the first major countries in the contemporary world to experience population decline. Today there are about one and a half million fewer Japanese than a decade ago, a decline in population that will dramatically intensify in the coming years; declining roughly eight million in the 2020s and ten million in the 2030s alone.

Some, such as Brad Glosserman in Peak Japan: The End of Great Ambitions, argue that Japan’s changing demographics will lead to a more inward-looking Japan in the coming years. The record thus far does not bear this out.  As I argued in Japan’s Security Renaissance, though Japan experienced its first decade both of population decline and what demographers now call “super-aging” (where over 20% of the population is over 65) in the 2010s, Japan’s military forces grew to be more capable than ever during this period. Recent defense discussion in Japan envisions further increases in capabilities, including perhaps crossing the Rubicon by developing strike missiles to enhance deterrence.

Other experts, including Japan Rearmed author Sheila Smith and RAND analyst Jeffrey Hornung, also have written important works that describe Japan’s increasingly formidable military. Conversion of Izumo-class destroyers to carry F-35 aircraft and deployment of additional Aegis-equipped destroyers (bringing the total to 8) are two of numerous examples of Japan’s expanding capabilities – again, despite the demographic challenges that Japan already is experiencing. But how long can this trend continue? Japan’s defense planners need to consider this question carefully as they work on a revised version of Japan’s formal national security strategy, which is expected soon. While, Japan’s military capabilities may be said to have improved despite demographic decline, the size of its military appears to be more directly affected, and the outlook for funding the military is unclear.

Japan’s Self-Defense Forces (JSDF) have not met their recruiting targets since 2014. In 2018, the JSDF set a goal of a standing force of 247,000, but only managed 227,000 – an 8% shortfall in total, but said to be around 25% at the lower ranks. This is not surprising since the number of Japanese between 18 and 26 years old, the target recruiting age, peaked 26 years ago, in 1994. Japan has not enjoyed a replacement birthrate since 1974. 

Japan’s Ministry of Defense (MOD) has considered numerous ways to address the shortfall in planned forces, which the 2019 National Defense Program Guidelines describe as “an imminent challenge”. In 2018 the JSDF raised the maximum age for new recruits from 26 to 32, the first increase since 1990. This year the retirement age for senior officers will start rising gradually. The MOD also set a rather modest goal to increase the share of women in the JSDF to 9% by 2030. Women made up just 7% of JSDF members in 2018, compared with an average of 11% among NATO countries. Other ideas include outsourcing some of the current functions of the JSDF, such as maintenance and, more controversially, disaster relief activities; and reallocation of forces from the Ground Self-Defense Forces (which comprise well over half Japan’s total forces) to the Maritime and Air Self-Defense Forces.

Can the trend of recent years of increasing defense spending continue over a projected future of declining total GDP as a result of population decline? Japan now runs the largest budget deficit of any developed country by far (4% of GDP) and a total debt of around $11 trillion, well over twice its GDP (versus about 104% of GDP in the United States); and this before the effect of the Covid-19 pandemic is considered, which has further ballooned spending. The difficulty of continuing the present political goal of a militarily stronger Japan will challenge leaders in a post-Abe Japan.

There is a bigger picture to consider, however: Japan is not aging and shrinking alone. Indeed, all of Japan’s neighbors—potential partners and security concerns alike—are facing a similar future, though on different timelines. Other U.S. allies in the region (South Korea and Thailand, though not the Philippines), and other security partners to Japan and to the United States (Taiwan, Singapore, and Vietnam), and, importantly, principal security concerns (China, North Korea, and Russia) as well. Working-age populations in South Korea, Taiwan, and China already have begun to shrink, with those states’ total populations projected to decline in the 2020s.

Meanwhile, new potential security partners for Japan will grow in population and also maintain robust youth populations. India and Indonesia are two of the top ten states for population growth through 2050. Not coincidentally, these states – and the demographically growing Philippines – are among those with which Japan is seeking to deepen security ties. Demography alone does not drive Japan towards these relationships; other factors such as shared concerns about China, geographic location, and convergence on maritime interests also are important.

New technologies also will play an important role in how Japan and other states manage the effects of demographic change on their security strategies. Robotics and other unmanned systems, including artificial intelligence, may offer some offsets for shrinking populations. At the same time, however, such new technologies themselves also are altering the nature of the regional security landscape. As Christian Brose wrote in Foreign Affairs: “artificial intelligence, autonomous systems, ubiquitous sensors, advanced manufacturing, and quantum science will transform warfare as radically as the technologies [of the early 20th century]” did in the last century. The emergence of new security domains in cyber and outer space creates new burdens. We cannot expect new technologies alone to offset challenges states face with demographic change: difficult choices lie ahead.

In sum, there will be a changing regional security landscape as a result of demographic change in the Indo-Pacific in the coming years – and both Japanese and U.S. military strategists will need to spend more focused attention coming to terms with this. The impact of demographic change on national security depends on a number of factors. These include the nature of the specific security threats that each state faces: some threats can be more readily addressed with less labor-intensive alternatives than others. The availability of technological solutions and whether the political and social systems are willing and able to adopt them or other options also is a big variable. Demography is not destiny – but will need to be reckoned with more than it has been to date, in Japan and elsewhere in the region.