Quantifying effects of spatiotemporal changes of urban and green areas on regional climate change: South Korean cities from the 1980s to the 2010s

Abstract

This study aims to quantify the effects of urban and green areas on regional climate change using time-series analysis of land use and land cover (LULC) for four decades starting from 1980 to 2019, obtained from the Ministry of Environment in South Korea (2020), in South Korean cities. This study employs the ordinary least squares (OLS) regression models to predict annually averaged temperature and heatwave days in individual South Korean cities. The results show that while the larger urban spaces have a statistically significant association with higher annually averaged temperature and heatwave days, the larger green spaces have a statistically significant association with lower annually averaged temperature. The effects of urban and green areas on regional temperatures are overestimated when it was not possible to differentiate between local and global climate effects. Additionally, the impact of urban and green spaces on regional temperature is more significant in highly populous cities (more than 1 million inhabitants) than those with lower populations. Although urban areas have a statistically significant association with annually averaged heatwave days, the effect is marginal, but the random effects over time, such as global climate change, are more significant. This study provides evidence for the impact of spatiotemporal changes in urban and green areas on regional temperatures and heatwave days. The findings suggest that policymakers should not expand urban spaces, in addition to enlarging green areas, particularly in cities of more than 1 million inhabitants.