A Century of Population Change with Regional Disparities in South Korea: Application of Cohort- component Analysis

South Korea's population has been experiencing a significant decline, raising concerns about potential changes in its demographic structure and regional imbalances in the future. While the general trend of population decrease is evident, its specific impact on spatial population patterns over the long term remains unclear. This study aims to examine the temporal and spatial variations in population over the next 100 years with 17 regions, providing insights to inform long-term planning. For its analysis, cohort-component modeling is utilized to forecast future populations with fertility and mortality rates as well as regional net-migration estimated by Statistics Korea which is one of government organizations. The younger the age group, the faster the population declines. The so-called 'super-aging era' has not yet been reached; it is projected to begin in earnest in about 20 years. Additionally, apart from Seoul, the capital of South Korea, and its neighboring administrative region, Gyeonggi-do, regional extinction is observed to start from areas farther away from these regions. Furthermore, it is predicted that 70 to 80 years from now, the rate of population decline will decrease, leading to population stabilization. Results emphasize the urgent need for strategic and practical, long-term regional planning and targeted policies to address the challenges posed by population decline and regional disparities as highlighting significant demographic and spatial shifts in South Korea's population over the next century.