Seas near Korea warming more than twice as fast as global average

The seas south of Korea are warming more than twice as fast as the global average, new research shows.

The Korea Institute of Ocean Science and Technology (KIOST) said Thursday that analysis of 20 years of observational data from the Ieodo Ocean Research Station found that average sea surface temperatures in the waters around Ieodo have risen 1.1°C since 2004.

That figure is more than double the 0.48°C average rise recorded across the world's oceans — excluding polar regions — over the same period. Researchers said the findings, drawn from direct field observations, confirm that Korea's southern waters are feeling the effects of climate change at an accelerated pace.

KIOST and the National Institute of Oceanography and Hydrography conducted the study jointly, drawing on sea surface temperature, air temperature, wind and other oceanographic and meteorological data collected at the Ieodo station since 2004. Researchers refined and corrected the two-decade dataset and calculated hourly averages to build a high-quality data archive.

This year's May readings were particularly striking: the average sea surface temperature around Ieodo reached 17.0°C, well above the 20-year May average of 15.0°C. Air temperature also hit 19.1°C, the highest on record during the observation period.

Researchers warned that the warming trend could lead to shifts in fish species distribution, a decline in marine resources and broader changes to ocean ecosystems.

"Satellites and computer simulations alone cannot precisely capture what is actually changing beneath the surface," said Kim Go-un, a researcher at KIOST's Marine Disaster Research Division. "These results were only possible because we had 20 years of direct observational data accumulated at the Ieodo station."

The Ieodo Ocean Research Station is Korea's first offshore ocean observation facility, located about 150 kilometers southwest of Jeju Island. Since its completion in 2003, it has continuously monitored sea surface temperature, air temperature, wind direction and wind speed.

The station's data have previously been used to analyze the weakening of Typhoon Soulik in 2018 and to study the prolonged high sea-surface-temperature event in the East China Sea in 2022.

"The Ieodo station is an observation hub capable of detecting climate change signals earlier than anywhere else," said Jeong Jin-yong, a KIOST researcher. "By making this dataset public, we have laid the groundwork for researchers around the world to use it in climate change studies."