February 10, 2025
SEOUL – Climate change has extended heat wave periods in South Korea, with projections saying they could last from May to September by 2100, according to the Korea Meteorological Administration’s first white paper on heat waves, released Sunday.
According to the KMA, heat waves are beginning to be observed earlier and are lasting longer in Korea. In the 1990s, heat waves were first observed in early July, but by the 2010s, the weather phenomenon was observed in late June. In 2024, the first heat wave of the year was also observed in mid-to-late June.
Though the timing of the most recent heat wave onset compared to the 1990s had not changed significantly, the state weather agency added that the overall duration of heat waves increased.
In 1994, Korea saw 28.5 heat wave days between June and August. While this was initially considered a record expected to occur only once every 81 years, it was surpassed in 2018 with 31 heat wave days. Last year, South Korea experienced 24 heat wave days, marking the third-highest number on record.
Also, between June and August, Korea saw a record 20.2 tropical nights, which refer to periods when the lowest temperature between 6:01 p.m. and 9 a.m. the next day remains above 25 degrees Celsius.
While 1994 and 2018 also experienced a significant number of tropical nights with 16.5 nights, Korea also saw tropical nights in 2024 lasting into September, logging the longest streak of tropical nights since 1973.
“The recent record-breaking number of heat waves and tropical nights with shorter recurrence intervals is closely related to the rising global temperatures caused by climate change,” explained the KMA through its white paper.
The KMA predicted that heat waves will only intensify in the Korean peninsula if greenhouse gas emissions are not reduced.
“By the year 2100, South Korea may see heat waves starting from May and lasting into September, with the average heat wave days increasing from the current 4.4 days to 17.4 days,” the KMA added.
Depending on what sort of actions are taken toward addressing climate change, the “intensity and duration of heat waves will vary greatly,” according to the KMA.
The weather agency further analyzed that extreme heat waves observed in 2018 could become the norm if the global average temperatures do not decrease and rise by more than 3 C above preindustrial levels. In 2018, Seoul saw temperatures rise as high as 39.6 C while Hongcheon-gun in Gangwon Province and Uiseong-gun in North Gyeongsang Province saw temperatures going above 40 C.
“Future heat wave pattern changes vary widely across different climate change scenarios,” said the KMA. “The intensity and duration of heat waves will vary widely depending on whether and how greenhouse gas emissions are reduced.”