As South Korea’s population falls, its military is shrinking rapidly. Is that a problem as North Korea ramps up its forces?

The writing has been on the wall for a long time: South Korea’s birth rate has dropped throughout much of the past decade, spelling trouble for the military as regional threats and global conflicts simmer.

Now, a new report has found that the number of South Korean troops declined by 20% in the past six years, in large part because of the dwindling pool of young men – reflecting the shrinking workforce and swelling elderly population in one of the world’s most rapidly aging countries.

The Defense Ministry report attributed the drop to “complex factors” including population decline and fewer men wanting to become officers due to “soldier treatment.” The report didn’t elaborate on that treatment but studies and surveys have previously highlighted the military’s notoriously harsh conditions.

As of July, the military had 450,000 troops, it said – down from 563,000 in 2019.

“If the number of standing army (members) continues to decline, there can be difficulties in securing elite manpower and limits in operating equipment,” warned the report, shared last week by lawmaker Choo Mi-ae.

The news comes at a bad time for South Korea, a key Western ally which hosts huge numbers of US troops and has a mutual defense treaty with Washington.

For one, South Korea has a reserve force of about 3.1 million men. While their training may be basic, it would give them the numbers needed for potential warfare – and that’s not including the 28,500 US troops stationed in the country.

Pyongyang is also facing its own population problems, with its fertility rate dipping in the last few years after the pandemic. The nation’s authoritarian leader, Kim Jong Un, pointed to the problem at a national conference of mothers in 2023, urging them to “give birth to many children” as a patriotic duty.

That could bode ill for a highly isolated nation with an economy that relies on labor-intensive industries like agriculture and mining, said Lee.

It’s hard to tell how much this has impacted the North Korean military so far. But the fact that Pyongyang has sent tens of thousands of troops to fight for Russia suggests Kim “doesn’t feel concerned about not having enough soldiers on board to do the task of defending the homeland,” Seiler said.