Prediction of land use changes according to SSP/SPA scenarios for Anseong City in response to a decrease in population

With the adoption of the Intergovernmental Panel on Climate Change's 6th Assessment Report, governments must prepare for the future by simultaneously considering both Shared Socioeconomic Pathways (SSPs) and Shared Policy Assumptions (SPAs) associated with the climate. Previous studies on land-use changes have focused on cities with growing populations. However, in some countries, such as Korea and Japan, there is predicted to be a decrease in the population, so research on the land-use patterns associated with urban shrinkage is needed. In the present study, scenario-based land-use changes were predicted for Anseong City , which is located in the metropolitan area of the Republic of Korea and for which future trends in population growth and decline are expected to be complex. First, factors affecting land-use changes based on international, national, and regional issues in Anseong City were reviewed. Following this, scenario goals for SSPs and policy responses were set. Consequently, the scenarios were structured and the variables set at the regional scale for probability-based model analysis using MaxEnt and Python. The scenario axis focused on urban development density (using population density) and the conservation of natural areas. In particular, Scenario 1 combined SSP1 (sustainability) with high-density development, the baseline combined SSP2 (middle of the road) with medium-density development, and Scenario 2 combined SSP3 (regional rivalry) with low-density development. Based on land cover data for 2020, land-use changes until 2100 were predicted for each scenario, with differences depending on the population, urbanization level, policies, and land-use regulations. In Scenario 1, bare lands arising from high-density development were developed into green areas, while, under Scenario 2, protected areas were lifted and the area used for low-density development was expanded. As a result, depending on the scenario, the forest/grass area in 2100 differed from the present by about -3% to 2%, and the size of the residential and commercial areas differed by approximately -50% to 157%. This study can be used as the basis for policy decisions for shrinking cities based on nature-based solutions , such as the density management of urbanized areas and the expansion of green infrastructure.