Accelerating population decline in small cities: The case of Japan

More than 15 years have passed since population in Japan began to decline. This paper addresses two questions concerning population decline in cities across the country. First, has the population decline occurred homogeneously or heterogeneously across cities? Second, if the decline has occurred in cities with specific characteristics, which factors are considered to be related to the downturn? The results of our analysis are as follows. First, population decline has turned to be heterogeneous and accelerated especially in small cities (less than 50 thousand people) since 2000s, which made difficult to hold the Gibrat's law. Second, in these small cities, population decline has happened by both natural changes and net migration. Third, negative net migration in these small cities occurs across all age groups (young, working and old generations), which has spontaneously happened with the decline of infrastructure, such as education service, employment opportunities and medical service. [Figure 9] Decomposition of population change: Natural change and net migration. Source: Ministry of Internal Affairs and Communication • Population decline in Japan has been heterogeneous across cities, with small cities experiencing the most severe decline since the 2000s. • In these small cities, both natural change and net migration affected population decline. • Net migration was observed in all age groups, reflecting the scarcity of infrastructure such as education service, employment opportunity, and medical service. • We also estimate the thresholds of the reduction in service with the population decline.