This summer, the Korean Peninsula experienced an extreme season characterized by alternating heat waves and heavy rains. Experts warn that this year is not an exceptional event but a harbinger of what will be repeated in the coming years.
According to the Korea Meteorological Administration, the average daily maximum temperature and average daily temperature from June 1 to August 26 recorded 30.6 degrees Celsius and 25.7 degrees Celsius, respectively, both achieving the highest on record. The number of heat wave days was 26.2, ranking third, while tropical nights recorded 14.3 days, marking the summer as "historically unprecedented."
In addition to the heat waves, brief heavy rains followed. As hot, humid air collided with cooler air from the north, localized heavy downpours fell across the southern regions and the metropolitan area.
On the 28th, Huh Chang-hui, a professor at Ewha Womans University in the Department of Climate and Energy Systems Engineering, noted, "The most significant feature of this summer's weather is the alternating occurrence of historically severe heat waves and heavy rains," adding that "extreme weather continues as if one is stepping across a stream."
Jeong Su-jong, a professor at Seoul National University Graduate School of Environmental Studies, said, "The Tibetan high-pressure system and the North Pacific high-pressure system cover the Korean Peninsula, causing a heat dome effect that leads to heat waves. The intense heat supplies a tremendous amount of water vapor to the atmosphere through the evaporation of the ground and seawater, and when convection is active on the hot ground, clouds produce rain, leading to inevitable heavy rains." In other words, the causes and effects of the heat waves also impact the heavy rains.
The fundamental cause of this phenomenon is climate change. The waters around the Korean Peninsula are warming at a rate faster than the global average. This results in increased evaporation from the sea and more water vapor in the atmosphere, leading to instability. At the same time, high pressure systems have intensified, making summer weather unpredictable and extreme.
In the future, heat waves are likely to be longer and stronger, while heavy rains are expected to occur more frequently and localized. National professor Jeong Jong-seong from Seoul National University said, "These changes are a glimpse of the long-term climate change in the East Asian monsoon region due to the accumulation of global warming, beyond temporary abnormal weather events," adding that "the intensity and frequency of heat waves and heavy rains will increase going forward."
Cho Cheon-ho, former president of the National Institute of Meteorological Sciences, explained, "Jet streams act as a kind of guardrail that prevents our country's weather from deviating from established paths, but global warming is changing the position and intensity of the jet streams, increasing weather variability," stating that, "In conclusion, global warming will make the conflicting extreme events of heat waves and heavy rains occur more frequently and with greater intensity during the summer months."
Experts believe that urban green spaces and park expansions, along with reductions in greenhouse gas emissions to address the climate crisis, are necessary to cope with the new summer climate patterns.
Choi Yong-sang, a professor at Ewha Womans University in the Department of Climate and Energy Systems Engineering, explained, "In the past 15 years, intense sunlight has been heating urban asphalt and buildings, causing the ground to become increasingly arid and making cloud formation difficult, solidifying a vicious cycle." He emphasized the importance of expanding and managing urban parks and forests.