REGION AND GEOGRAPHY ISSN:2586-1468(Online) 지역과 지리

The purpose of this study is to examine the spatio-temporal changes of heat waves in the early 21^st century and their projected changes in the later 21^st century in South Korea. To do this, heat index (HI), which quantifies human-sensible temperature considering the synergistic effects of high temperature and high humidity, is calculated at daily scale for the early 21^st century using the MKPRISM v.2.1 reanalysis data set and for the later 21^st century using high-resolution climate change scenario data for South Korea based on the latest greenhouse gas emission scenarios (Shared Socioeconomic Pathways, SSP). Temporal comparisons show that under both high (SSP5-8.5) and mid-level (SSP2-4.5) greenhouse gas emission scenarios, the mega-heat waves exceeding emergency level (exceeding 42°C of daily mean HI) will occur more frequently with more intensity toward the broader regions near large rivers in Korea in the later 21^st century (2091~2100) compared to those for the present. In terms of duration, while mega-heat waves in the early 21^st century are limited to the peak summer period (late July to early August) of specific years only, based on SSP5-8.5 (SSP2-4.5) the extreme episode persisting for 60 (30) consecutive days or longer around the peak summer period is projected to frequently occur around the middle and lower reaches of major rivers in the later 21^st century. These findings indicate that the government must take proactive measures to prepare for massive casualties caused by mega-heat waves particularly in densely populated metropolitan areas as well as for the drastic reduction in water resources and food production resulting from mega-droughts in rural areas along major rivers, which are identified as key hot spots of mega-heat waves in South Korea in the later 21^st century.