Extreme heat spreads nationwide as highest emergency alert issued for Seoul

The extreme heat that gripped southern regions of Korea expanded to the central region and the greater Seoul area on Monday.

Authorities issued the first-ever emergency heat wave warning — the highest level in Korea's three-tier heat alert system — for southern Seoul and some parts of Gyeonggi.

Gwangju's daytime high reached a record 38.8 degrees Celsius (101.8 degrees Fahrenheit), the highest temperature recorded in the city's 87 years of weather observations, according to the Korea Meteorological Administration (KMA). The previous record was 38.5 degrees Celsius, set on Aug. 15, 2018.

Wando in South Jeolla and Namwon in North Jeolla also set new local records at 38.5 degrees Celsius and 37.6 degrees Celsius, respectively.

The KMA compiles temperature rankings based on observations from the Automated Synoptic Observing System, which uses 97 stations to record surface weather conditions simultaneously at designated times nationwide.

Agonized capital, sweltering south

Temperatures also rose sharply in Seoul compared to the previous day.

On Monday, Guro District, western Seoul, recorded a daily high of 39 degrees Celsius and Gangnam District, southern Seoul, reached 38.7 degrees Celsius.

The Seoul Metropolitan Office of Meteorology under the KMA issued an emergency heat wave warning for southern Seoul and the Gyeonggi cities of Hanam, Osan and the western part of Yeoju. The warning took effect at 11 a.m. on Monday.

The extreme heat spread westward across the Korean Peninsula after prevailing winds shifted from westerly to easterly, meteorologists said. As the easterly winds crossed the Taebaek Mountain Range, they became hotter and drier and drove temperatures sharply higher.

"Low-level easterly winds are expected to cross the mountain range and push temperatures significantly higher in parts of the Seoul metropolitan area, and the current heat is expected to continue for the time being," the Seoul meteorology office said.

Weather officials advised people to take special safety precautions.

"The first emergency heat wave warning for the greater Seoul area signals an extreme level of heat that could make it difficult even for healthy people to carry on with normal daily routines or outdoor activities," Kim Hyun-kyung, head of the Seoul Metropolitan Office of Meteorology, said. "People in affected areas should stop outdoor activities immediately, move to a cool place and check on the safety of family members and neighbors."

The scorching conditions continued across the Gyeongsang region, where multiple locations recorded temperatures above 40 degrees Celsius. Miryang in South Gyeongsang reached 41 degrees Celsius, while Uiryeong and Haman in the same province recorded 40.8 degrees Celsius and 40.3 degrees Celsius, respectively.

New normal? May be

The unprecedented temperatures have fueled concerns among experts that extreme heat is becoming the country's "new normal."

An analysis of Korea's annual temperature records since modern weather observations began in 1904 illustrates how rapidly the ceiling has risen.

Daegu became the first location to record 40 degrees Celsius on Aug. 1, 1942. It took another 76 years before Hongcheon County in Gangwon became the first to exceed 41 degrees Celsius on Aug. 1, 2018. On Sunday, Yangsan in South Gyeongsang reached 42.5 degrees Celsius, breaking the 42-degree Celsius threshold for the first time.

In other words, it took 76 years for Korea's all-time temperature record to rise from 40 degrees Celsius to 41 degrees Celsius. It then climbed another 1.5 degrees Celsius in just eight years.

The intensity of extreme heat has become especially pronounced in the 2020s.

The number of days under extreme heat during the 2020s has roughly doubled compared with the 1910s. The country's annual average temperature had risen by 1.9 degrees Celsius over the century from 1910 to 2010, but it has already increased by another 0.9 degrees Celsius during the 2020s alone.

Sea water makes hot even hotter

Meteorologists say the accelerating warming trend, combined with unusually warm waters across the North Pacific, is intensifying heat waves.

Sea surface temperatures around the Korean Peninsula and across the North Pacific have remained at record or near-record highs since the early 2020s.

"As the ocean warms, the hot and humid North Pacific High is expanding farther into the mid-latitudes and increasingly covering the Korean Peninsula," said Kim Baek-min, a professor specializing in environmental atmospheric sciences at Pukyong National University. "That is creating conditions in which heat waves last longer and tropical nights become more severe."

Globally, scientists also warned that this year could become the hottest on record, noting that the strongest "super El Niño" in 150 years could make heat waves even more severe. A super El Niño occurs when sea surface temperatures in the eastern Pacific rise more than two degrees Celsius above average.

"El Niño is strengthening — adding fuel to a planet already on fire with scorching heat domes, apocalyptic wildfires and record hot seas,” United Nations Secretary-General António Guterres said.

BY CHON KWON-PIL [lee.soojung1@joongang.co.kr]