Climate Change Could Bring Over 50 Days of Hazardous Heat Annually to South Korea

South Korea faces a stark future of escalating heat stress if greenhouse gas emissions continue unabated. Projections indicate that by the late 21st century, the country could experience over 50 days per year where outdoor conditions are hazardous enough to cause heatstroke even while resting.

The Korea Meteorological Administration's "National Climate Change Standard Scenario" paints a grim picture under a high-carbon scenario. Currently, the average summer heat index (WBGT), which considers temperature, humidity, wind, and radiation, stands at 26.9°C. Days exceeding 33°C, a threshold indicating high heat stress even during rest, occur only about 1.8 times annually. However, by 2081-2100, this average heat index is projected to soar to 33.2°C, with the number of days above this critical level exploding to 51.6.

This dramatic increase means that conditions where individuals can easily suffer heatstroke simply by being outdoors could become the norm. The scenario highlights a significant regional variation, with coastal areas like Jeju and South Jeolla, and the West and South coasts experiencing higher heat indices due to humidity. Under the high-carbon scenario, these areas could see temperatures exceed 34°C.

Conversely, a low-carbon scenario, which involves active emission reductions, offers a more moderate outlook. In this scenario, the average summer heat index is projected to reach 29.5°C, significantly mitigating the risk of severe heat-related illnesses. The study also noted that the Seoul metropolitan area and South Chungcheong province are expected to see particularly sharp increases in heat index compared to other regions.

Beyond the heat index, projections for days with a maximum temperature of 33°C or higher also show a substantial rise. Currently averaging 13.1 days nationwide, this figure is expected to jump to 35.2 days under the low-carbon scenario and a staggering 80.4 days under the high-carbon scenario by the end of the century.

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If greenhouse gas emissions are not reduced, the summer season in Korea in the latter half of this century will have more than 50 days a year where heatstroke can occur just by being outdoors.