On Christmas Day, Dec. 25, tourists and visitors enjoy the winter sea at Hamdeok Beach in Jocheon-eup, Jeju City./Courtesy of Yonhap News Agency

Forecasts suggest that changes in the waters surrounding the Korean Peninsula due to climate change will reach a serious level. By the end of the 21st century, sea surface temperatures are expected to rise by up to 4.5 degrees, and marine heat waves are predicted to occur for more than 295 days a year. In particular, in a high-carbon emission scenario, ecosystem destruction and extreme weather conditions are expected to become more severe.

The Korea Meteorological Administration analyzed future projections of three marine climate factors (sea surface temperature, surface salinity, and sea level) and marine heat waves in the waters surrounding the Korean Peninsula until 2100 based on high-resolution marine climate change scenarios. The forecast data was detailed using data obtained from the global climate change prediction model developed by the National Meteorological Science Institute (K-ACE), with the participation of research teams led by Professor Song Ha-jun of Yonsei University and Professor Tak Yong-jin of Gangneung-Wonju National University.

An analysis of future marine climate projections by decade in the marine weather warning zones showed that changes in marine climate in the waters surrounding the Korean Peninsula and their impacts until 2100 are more pronounced in a high-carbon scenario compared to a low-carbon scenario when compared to the last decade (2015–2024).

In the low-carbon scenario, sea surface temperatures are expected to rise until 2050 before stabilizing, but in the high-carbon scenario, sea surface temperatures are projected to continue rising, with an average increase of 4.28 degrees by the end of the 21st century (2091–2100) compared to the last decade. In particular, in the western sea and the central eastern sea, the sea surface temperature is expected to rise by about 4.5 degrees, which is more than 0.2 degrees higher than the overall average (4.28 degrees).

An analysis of the phenomenon of 'marine heat waves,' defined as the top 10% of daily average water temperatures persisting for more than five days, showed that both the frequency and intensity of occurrences by the end of the 21st century are expected to increase compared to the last decade, with significant fluctuations in the high-carbon scenario. In the high-carbon scenario, the number of occurrence days is projected at 295.5 days, and the intensity is expected to rise by 2.54 degrees, which is more than 100 days and over 2 degrees higher than in the low-carbon scenario, indicating that most of the year will be exposed to high-intensity marine heat waves.

The Korea Meteorological Administration explained that 'with the increase in the frequency and intensity of marine heat waves, the impacts of marine climate change, such as the destruction of marine ecosystems in the waters surrounding the Korean Peninsula, are expected to intensify, raising concerns about an increase in extreme weather, including heat waves.'

In the high-carbon scenario, it is also anticipated that by the end of the 21st century, sea levels will rise approximately 0.56 meters, which is about 0.21 meters higher than in the low-carbon scenario. By area, the southern part of the East Sea is expected to rise by 0.58 meters, the eastern part of the South Sea by 0.57 meters, and the central part of the East Sea by 0.56 meters, while the variations by area are not large. For surface salinity, in the high-carbon scenario, a continuous decrease is expected from the 2040s, with the decrease by the end of the 21st century expected to be twice that of the low-carbon scenario.

The rise in sea surface temperature and sea level is closely related to an increase in the intensity of storm surges and extreme wave heights. Changes in sea surface temperature and surface salinity act as factors causing damage to the fishing industry, including fisheries and aquaculture in the waters surrounding the Korean Peninsula. Therefore, the Korea Meteorological Administration plans to provide the future marine climate change scenarios released this time through climate change situation maps and utilize them in the development of national climate change standard scenarios for the marine sector.

Korea Meteorological Administration head Jang Dong-eun noted, 'Detailed future forecasting data on the waters surrounding the Korean Peninsula will serve as crucial foundational data for adapting to and responding to the climate crisis in the marine sector,' adding that 'the Korea Meteorological Administration will continue to strive to produce reliable climate change prediction data as the overall institution for monitoring and predicting the climate crisis.'