Korea’s seas are warming more than twice as fast as the global ocean

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The waters around South Korea are warming at one of the fastest rates in the world, with the number of marine heatwave days increasing 3.7-fold over the past decade, according to the country’s meteorological service. Sea surface temperatures around the Korean Peninsula have risen by 0.7 degrees Celsius over the past 10 years — more than twice the global increase of 0.3 degrees.The Korea Meteorological Administration on Wednesday released its analysis of climate trends and future projections for waters surrounding the Korean Peninsula. The study examined observations collected between 2016 and 2025 by the agency’s marine weather buoys, along with global sea surface temperature data. The findings were compared with the 1991-2020 climate averages for Korea and the world and used climate-change scenarios to project future changes.Over the past decade, the average sea surface temperature around Korea was 18.1°C (64.58°F), 0.7°C above the 1991-2020 average. Globally, the average sea surface temperature during the same period was 18.5°C, or 0.3°C above the long-term average.The warming trend has also accelerated. Since 1991, sea surface temperatures around Korea have increased by about 0.3°C per decade, but the increase reached 1.2°C over the most recent 10-year period.The four years with the highest annual average sea surface temperatures — 2024, 2025, 2021 and 2023, in descending order — all occurred in the last five years.