Korea's sea surface temperatures hit record high amid ocean warming

Korea's average sea surface temperature in the first half of this year reached the highest level ever recorded, the National Institute of Fisheries Science announced Thursday, raising fresh concerns about ocean warming.

Satellite data analysis covering 26 years since 2001 showed that the average sea surface temperature in Korean waters during the first half of this year stood at 17.17 degrees Celsius — 1.17 degrees higher than last year and 0.52 degrees above the previous record set in 2020.

Direct ocean surveys under the institute's fixed-line marine observation program — running since 1968, with six annual surveys of 207 stations at 5 meters depth across Korean waters using fisheries research vessels — also recorded a first-half average surface temperature of 15.34 degrees Celsius, the highest since the program began. The results show that ocean warming is advancing clearly across all Korean waters.

The institute attributed the elevated temperatures primarily to persistently high air temperatures since the second half of last year and prolonged clear skies this spring, which intensified solar heating of the sea surface. A stronger-than-normal inflow of the warm Tsushima Current also continuously supplied warm water to Korean waters, sustaining the high temperatures.

As of this month, the global average sea surface temperature stands at 20.98 degrees Celsius, surpassing the previous record set in 2024 — a sign that rapid ocean warming is under way not only in Korean waters but across the world's oceans.

Kwon Soon-wook, director of the National Institute of Fisheries Science, said the institute would "further strengthen its scientific capabilities for monitoring and forecasting climate change."