[Opinion] The Sudden Spring Unwelcome Guest 'Abnormal Low Temperature' Following COVID-19

On the 1st, as the cold snap continues, commuters are waiting for the pedestrian signal at Gwanghwamun Intersection in Seoul. Photo by Mun Ho-nam munonam@

According to the Korea Meteorological Administration, last winter was the warmest since 1973. Due to global warming, temperatures in the early spring period (March to mid-April) this year are expected to be higher than the average (1981?2010), and in the late spring period (mid-April to May), a rapid temperature rise is anticipated, bringing early heat.

The Rural Development Administration predicts that the abnormal high temperatures during winter will cause the budding and flowering periods of fruit trees and crops to advance by 4 to 7 days. In such cases, damage from pests and diseases (diseases or pests that harm crops) may occur. Fruit trees and crops may become vulnerable to sudden cold spells because their roots are less prepared to supply nutrients, and the stems or leaves grow quickly and weakly due to the abnormal warmth.

If the underground temperature rises above 7℃ between March and April, buds will sprout and flowers will begin to bloom on fruit trees and crops. Between April and May, flowers bloom and pollination occurs on fruit trees such as apple and peach trees.

This period is the most vulnerable time for fruit trees and crops due to temperature fluctuations. If temperatures suddenly drop below -2℃ during this time, the pistils of blooming flowers may wither, preventing fruit formation. The activity of bees and butterflies, which transfer pollen from stamens to pistils, also diminishes, potentially worsening the yield of fruit trees and crops.

Every year, damage to crops caused by sudden temperature changes in spring from late March to early May occurs. According to the Ministry of Agriculture, Food and Rural Affairs, there were nine instances of crop damage due to low temperatures in spring over the past ten years (2009?2018).

A recent representative case of sudden abnormal low temperatures in spring was recorded between April 4 and 6, 2014, when the average temperature dropped to -3.2℃. At that time, crops in the Gyeonggi, Chungbuk, Chungnam, Gyeongbuk, and Sejong regions suffered cold damage. On May 6?7 of the same year, the latest snowfall in 33 years occurred in Daegwallyeong, and frost in the Boseong area of Jeonnam caused discoloration of green tea leaves.

Between March 23 and 25 and April 1 and 3 last year, minimum temperatures fell below freezing, causing cold damage to fruit trees and crops in Jeonnam, Gyeongbuk, Gyeongnam, and Ulsan regions. Heavy snow fell in Gangwon and Gyeongbuk regions between April 9 and 10. Especially due to the abnormal low temperatures in April, fruit trees and crops in the southern inland areas of the Korean Peninsula, where flowering occurs early, suffered significant cold damage. Between May 7 and 9, freezing temperatures and frost in some inland and mountainous areas caused flower buds of fruit trees to freeze and crops to wither.

Typically, a frost damage advisory is issued when the minimum temperature is expected to fall below -2℃. According to research by the APEC Climate Center, it is necessary to assess the possibility of frost by considering different minimum temperatures for each region, including topographical factors, and to prepare accordingly.

The Korea Meteorological Administration forecasted a sudden temperature drop (from -5℃ to -1℃) on April 7?8, 2018. Accordingly, the government urged farmers to prepare in advance for abnormal low temperatures in spring. However, some farms did not install thermal covers or turn on heating, resulting in damage to flowers, vegetables, and other facility crops.

Kwon Won-tae, Director of APEC Climate Center

Due to recent abnormal high temperatures in winter, the budding and flowering periods of fruit trees and crops have advanced, increasing concerns about cold damage caused by sudden abnormal low temperatures in spring. The government and local authorities provide necessary recommendations based on meteorological and climate information to respond to abnormal low temperatures in spring, so it is important for farmers to pay attention to these. Appropriate meteorological and climate forecast information can be effectively used to address issues in the agricultural sector cultivating fruit trees and crops affected by abnormal low temperatures in spring.

This is possible on the foundation of reliable meteorological and climate forecast information. To reduce uncertainty and increase reliability in meteorological and climate forecasting, it is time for the government and domestic meteorological and climate experts to take greater interest and make more efforts than before.

Won-Tae Kwon, Director of APEC Climate Center