'Feels Like -20°C' Worst Cold Wave... Why Is Winter Getting Colder Despite Global Warming?

Arctic Warming Worsens Surrounding 'Jet Stream'
Cold Air Flows into Mid-Latitudes and the Korean Peninsula

The severe cold, with wind chill temperatures fluctuating between minus 10 to 20 degrees Celsius, is expected to continue throughout the weekend starting from the 23rd. There are concerns that this could set a new record for the 'worst cold wave ever,' accompanied by heavy snowfall and burst water pipes. While global warming is causing temperatures to rise steadily, why is the winter cold becoming harsher every year?

Worst Cold Wave with Wind Chill Below -20 Degrees

On the afternoon of the 22nd, a citizen wearing a hat is walking on Bukchon-ro, Jongno-gu, Seoul. / Photo by Yonhap News

According to the Korea Meteorological Administration, the minimum temperature on Friday the 23rd morning was recorded at -19 degrees Celsius. The actual wind chill temperature felt by people can drop 3 degrees lower to -22 degrees Celsius. Wind chill temperature is calculated by measuring both temperature and wind speed, representing the coldness felt on the skin; for every 1 m/s increase in wind speed, the wind chill temperature drops by 2 degrees.

The 'record-breaking cold wave' with biting cold and piercing winds is expected to continue through the weekend. The Meteorological Administration forecasts severe cold around -10 degrees Celsius on the 24th and 25th as well.

Winter Gets Colder 'Because of' Global Warming... Due to Weakening Arctic Jet Stream

Although global warming is causing the Earth's average temperature to rise, why is the winter cold becoming more severe each year? In fact, until last month, domestic temperatures were higher than average.

According to Meteorological Administration data, the minimum temperature in November has steadily increased since recording 0.9 degrees in 2017. This year, the minimum temperature on the College Scholastic Ability Test day (November 17) was a mild 3.5 degrees Celsius. Last month, unusual phenomena such as early blooming of spring flowers like azaleas and forsythias were observed across the country.

The reason temperatures dropped sharply in just one month is paradoxically due to intensified global warming. The air currents affecting winter weather on the Korean Peninsula are cold and dry air descending from the Arctic. However, due to recent warming, the Arctic is gradually becoming warmer, and glaciers are melting.

The Arctic Oscillation (AO) index, compiled monthly by the U.S. National Oceanic and Atmospheric Administration (NOAA), has been approaching zero again since last month. / Photo by U.S. National Oceanic and Atmospheric Administration official website capture

This climate change weakens the 'jet stream,' a fast and narrow air current circulating around the Arctic. Because of the weakened jet stream, cold air that used to circulate around the Arctic suddenly descends to mid-latitudes, causing temperatures on the Korean Peninsula to drop further.

This phenomenon can also be explained by the 'Arctic Oscillation (AO)' index, compiled monthly by the U.S. National Oceanic and Atmospheric Administration (NOAA). The Arctic Oscillation measures the strength of the vortex rotating around the polar region; when this value drops below zero (negative), it indicates a weakened jet stream. Between 2020 and January of the following year, the AO value fell into negative territory, resulting in a much colder winter than usual last year. The AO recorded 0.344 last month, beginning to approach zero again.

United States and Canada Also Facing Crisis Due to Abnormal Cold Waves

South Korea is not the only country suffering from harsher cold waves due to global warming. According to local media such as CNN, northern parts of the United States and Canada, both Northern Hemisphere countries, have also issued cold wave warnings in several regions recently.

In particular, the U.S. National Weather Service (NWS) reported that starting from the 22nd (local time) through around Christmas, a so-called 'bomb cyclone' phenomenon is expected to strike the United States. A bomb cyclone is an abnormal weather event accompanied by heavy snowfall and strong gusts. It occurs when Arctic air currents in winter meet moist air from the Atlantic Ocean, and this too results from the weakening of the Arctic jet stream and the decline of the AO value.

This content was produced with the assistance of AI translation services.