Without Greenhouse Gas Cuts, Most of South Korea to Turn 'Subtropical' by End of Century

If greenhouse gas emissions continue at their current rate, the climate of the entire country, except for the Yeongseo region of Gangwon Province, is projected to become subtropical in the late half of this century (2080–2100).

On Tuesday, the Korea Meteorological Administration (KMA) released a forecast based on observation data from 66 locations nationwide from 1981 to 2025 and national standard climate change scenarios, stating, "Under a high-carbon scenario, the climate of most regions across the country, except for Gangwon Yeongseo, will change to subtropical in the late half of this century."

The KMA defined the climate based on the Trewartha climate classification.

The Trewartha classification, created by American geographer Glenn Thomas Trewartha by improving the Köppen climate classification, is evaluated as best reflecting global vegetation zones and is the most widely used in related domestic research.

Under the Trewartha criteria, a subtropical climate is defined as having a mean temperature of 18°C (64°F) or below in the coldest month, and eight to 12 months with a monthly average temperature of 10°C (50°F) or above.

Currently, most regions in South Korea are classified as temperate climate zones.

Based on the climatological normal (1991–2020 average), out of 62 observation points nationwide excluding four in Jeju, about 84% (52 points) have seven or fewer months in a year with a monthly average temperature of 10°C (50°F) or above.

However, about 79% (49 points) had a monthly average temperature of 10°C (50°F) or above for seven months from April to October, corresponding to a "temperate climate close to subtropical."

Looking at regions that meet the subtropical criteria, there were a total of 13 locations based on the 30-year period from 1981 to 2010—including four points in Jeju (Jeju, Gosan, Seongsan, Seogwipo) and Mokpo, Wando, Yeosu, Namhae, Tongyeong, Geoje, Changwon, Busan, and Pohang—but this increased to 14 locations based on the 1991–2020 period with the addition of Ulsan.

Based on the 2001–2025 period, the results were the same as the 1991–2020 period.

When broken down by decade, there were 14 locations meeting the subtropical criteria in the 1990s and 2000s (the same as those meeting the criteria in 1991–2020), and 15 in the 2010s with the addition of Gwangju.

Looking only at the last 10 years (2016–2025), Uljin and Gangneung also met the subtropical criteria, bringing the total to 17 locations classified as subtropical.

The reason for the increase in locations meeting the subtropical criteria is the rise in average temperatures in November.

Since the 2010s, regions meeting the subtropical criteria, which were previously limited to Jeju and the southern coast, have expanded northward to the inland areas of South Jeolla Province and the East Coast.

Regions like Gwangju, Uljin, and Gangneung, which came to meet the subtropical criteria in the 2010s or the last 10 years, all met the standard as their average November temperatures rose to 10°C (50°F) or above.

Other East Coast regions such as Yeongdeok and Sokcho, as well as other inland southern regions like Jeonju and Daegu, have also seen their average November temperatures rise close to 10°C (50°F) over the last 10 years, putting them on the verge of meeting the subtropical criteria.

The KMA stated, "The subtropical climate is gradually moving northward from the southern coast to inland southern regions and is intensifying along the East Coast," adding, "The rapid rise in sea surface temperatures in the East Sea is analyzed to have significantly raised temperatures in the East Coast region over the past 10 years."

In the case of the central region, no area has met the subtropical criteria yet, but inland areas such as Boryeong, Cheongju, and Daejeon are showing signs of approaching the subtropical standard as their average March temperatures rise.

While South Jeolla Province and the East Coast are meeting the subtropical criteria as their average November temperatures approach 10°C (50°F)—meaning high temperatures persist until late autumn—inland areas of the central region are showing a trend toward meeting the criteria as early spring warmth begins, with average March temperatures rising toward 10°C (50°F).

Future projections show that under all climate change scenarios, the climate of South Jeolla Province, South Gyeongsang Province, coastal areas nationwide, and parts of major cities will turn subtropical in the first half of this century (2021–2040).

The outlook for the late half of this century varied depending on the climate change scenario; under the low-carbon scenario (SSP1-2.6, where renewable energy technologies develop, fossil fuel use is minimized, and eco-friendly sustainable economic growth is achieved), the subtropical climate only showed a slight expansion inland.

However, applying the high-carbon scenarios SSP3-7.0 (where climate change mitigation policies are passively pursued, technology development is delayed, and social structures are vulnerable to climate change) and SSP5-8.5 (which focuses on rapid industrial and technological development, high fossil fuel usage, and reckless urban-centered development), the climate of most regions except for Gangwon Yeongseo is expected to turn subtropical.
※ Please note: This article was translated by AI and may contain errors.