A citrus farmer in Jeju Island said, looking at a pile of citrus fruits that were split and discarded due to heat and fruiting, "The rotten smell in the orchard stabbed my nose; and bugs appear. I can't take the harvest anywhere, so I have to leave it on the orchard floor."
Citrus, a representative specialty product representing Jeju and the life industry of the people, is suffering from climate change. In particular, during the longest rainy season this year, a series of typhoons poured a record heavy rain, and some citrus fruits absorbed moisture like water balloons, and were exposed to various diseases during the production process.
Heat and phenomena are typical. It refers to a phenomenon in which the flesh quickly absorbs moisture when it suddenly rains after the summer heat has passed and the skin is torn.
The Jeju Agricultural Research and Development Institute estimates that heat and damage occurred at a minimum of 5% to a maximum of 40% per farm. One of the citrus diseases of concern when it rains a lot is black spot disease. The black spot, which causes the most damage to open-air citrus, has a very high risk of occurrence when the temperature is over 20 degrees and the citrus fruit is wet for 12 hours or more.
A lot of rain can affect the sugar content as citrus trees absorb too much moisture. An official of the Jeju Agricultural Research and Development Institute explained, "If the soil has a lot of moisture, the citrus tree passively absorbs water, causing the water to fill up in the fruit beyond an appropriate amount and lower the sugar content."
It's a problem even if it doesn't rain too much. When it is wet, bacteria are formed, and when it is dry, pests are formed. At present, tangerine farms are in full swing. Thrips are insects that are small enough to be difficult to see with human eyes, and they eat citrus peels and reduce their marketability. The Agricultural Technology Institute estimates that the production of citrus fruits this year will be different from 528,000 tons originally expected due to a series of natural disasters.
The impact of climate change on citrus cultivation is not just a matter of this year. The citrus flower blooms are getting faster. Citrus flowering time increased by two days from the average of May 16 in the 1970s to May 14 in 2004-2013. Experts predict that the flowering period could be accelerated to May 10 in the 2030s and May 7 in the 2050s as the average temperature rises gradually. The faster the citrus bloom and germination, the longer the growing period and the late frost damage may occur.
The 'Korea Climate Change Assessment Report 2020,' published by the Ministry of Environment in July, predicted that in the 2030s, the cultivation sites for Onju citrus will increase mainly in the coastal area of ​​Jeonnam. In addition, from the 2060s, it has predicted that the cultivation site will gradually increase to the mountainous areas of Jeju, Jeonnam, Gyeongnam, and the coastal areas of Gangwon-do.
The report predicted that the cultivation possibility also expanded to Gyeongbuk, Chungnam, and Jeollabuk-do, and that in Jeju in the 2090s, cultivation in Jeju became virtually impossible as the cultivation area decreased except for mountainous areas within Hallasan National Park.