The national institute of fisheries science (NIFS; President Kwon Soon-wook) announced that the average sea surface temperature (SST) in Korean waters during the first half of 2026 (January-June) reached an all-time high, based on the results of comprehensive analysis of observation data collected by satellites and fisheries research vessels(R/Vs). 

An analysis of satellite data from the recent 26 years (2001-2026) showed that the average SST in Korean waters during the first half of this year reached a record high of 17.17℃, exceeding the 2025 average by 1.17℃ and the previous record set in 2020 by 0.52℃.

In the serial oceanographic observation survey* conducted by NIFS since 1968, the SST in the first half of this year reached a record high of 15.34℃, demonstrating that significant ocean warming has occurred across Korean waters.

*Since 1968, NIFS has been conducting biomonthly surveys at 207 stations (5m depth) in Korean waters using its fisheries research vessels (R/Vs)

The primary drivers of elevated water temperatures during the first half of the year appear to be intensified surface heating resulting from a prolonged period of sunny weather in the spring, coupled with persistently high temperatures since the second half of last year. The analysis also pointed to the continued influx of Tsushima Warm Current into Korean waters –stronger than average year- as another factor contributing to the persistently high water temperatures.

The global SST is no different from that in Korean waters. As of July, the global average SST is 20.98℃ higher than the previous all-time high record set in 2024, indicating that global ocean warming is intensifying at an alarming rate and affecting not only our domestic waters but all marine environments around the world. 

“As sea temperatures in domestic waters reached a record high in the first half of this year, there have been growing concerns over ocean warming,” adding, “For that, NIFS will strive to strengthen its scientific research capacity for climate change monitoring and advanced climate projections,” said the president of NIFS.