Future Extreme Climate Analysis of Jeju Using Climate Change Scenario and ETCCDI Index

According to the fifth IPCC report, artificial greenhouse gases are at their highest level since they were first observed, and climate change is expected to have a significant impact on the ecosystem, necessitating a response from Korea. For the purpose of this study, Jeju Island was selected as the target area; the annual average precipitation of the region exhibited a 10% increase from 1,780 mm in 1991 to 1,961 mm in 2019; the annual average temperature increased by 0.3 ℃ over 10 years from 1961 to 2019. There are three weather stations (Jeju, Seogwipo, and Seongsan) on Mt. Halla, which is 1,950 m above sea level; among these stations, Jeju Island's climate patterns are the most atypical. The World Meteorological Organization’s (WMO) Expert Team on Climate Change Detection and Indices (ETCCDI) for Jeju Island's extreme climate analysis used 8 of the 27 indexes that are most closely related to climate. For analysis purposes, existing RCP 8.5 climate change scenario data were categorized as: past (data analyzed from 1991 to 2019), and future (data analyzed from 2020 to 2100). According to the extreme climate analysis, Jeju Observatory recorded its highest temperature at 25 ℃ while exhibiting an increasing trend, and at Seongsan, highest temperature of less than 0 ℃ was recorded for more than 40 days in 1996. According to the climate change scenario, the number of hot days in Jeju, Seogwipo, and Seongsan is increasing, but the number of frost days has converged to zero with the progression of the second half of the 21st century. Japan's highest temperature chart shows that 40 ℃ spike in Jeju compared to other regions. Thus, this study highlights the necessity of considering the climate characteristics of each observatory, and the implementation of urban planning and disaster prevention measures.