Seas around Korean Peninsula warming twice as fast as global average

The seas surrounding the Korean Peninsula are heating up at an alarming rate, with temperatures rising more than twice as fast as the global average. In the last decade, from 2016 to 2025, the average sea surface temperature in these waters increased by 0.7 degrees Celsius compared to the 1991-2020 baseline.

This significant warming trend has led to a dramatic increase in marine heatwaves, a severe form of extreme climate event. These heatwaves, characterized by prolonged periods of abnormally high sea temperatures, now occur more frequently and with greater intensity. They can persist for several months, impacting vast oceanic regions.

Data from the Korea Meteorological Administration reveals that the average sea surface temperature has risen by 0.3 degrees Celsius per decade since 1991. However, the rate of warming has accelerated sharply in the most recent decade, with temperatures increasing by 1.2 degrees Celsius per decade. This acceleration is significantly higher than the trend observed over the previous 25 years (1991-2015).

The frequency of marine heatwaves has also surged. The average number of days experiencing marine heatwaves annually in the last decade was 83.3 days, a nearly fourfold increase from the average of 22.6 days in the baseline period. What once lasted about 3.2 weeks per year now extends for approximately 2.8 months, with an intensity of 2.1 degrees Celsius above normal.