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By Kim Jeong-su, Environmental Correspondent

Increased double cropping in North China Plan (NCP) is causing summer climate change in South Korea, reports a study multiply-authored by researchers from South Korea, China, the United States, and France.

The study co-designed by SNU Earth and Environmental Sciences Professor Ho Chang-Hoi, was published in the online edition of Nature Climate Change, a leading journal on the science of climate change, on June 9. According to the paper, China abandoned single cropping in favor of double cropping of wheat and corn in the NCP in the mid-1980s to meet increasing food demands.

Ho‘s team has found that the change in planting has resulted in a 1.02 degrees Celsius rise in the region’s maximum daily temperature range for the months of June and July, which coincides with the rainy season in South Korea. The sharp rise is being attributed to the practice of covering the farmland‘s surface for the two-month inter-cropping season between the wheat harvest and corn sprouting. As a result, an area nearly three times the size of the Korean Peninsula, at a distance away that is only two to three times the distance from Seoul to Busan, is being turned temporarily into a vast desert.

According to the study, the desertification is driving rainfall to extremes of lower rainfall in drier years and heavier rainfall in wetter ones during the traditional monsoon season of June and July. The results show an increase of 120 mm during times of heavy rainfall, with a corresponding drop during dry periods. With June to July rainfall typically averaging around 600 mm in South Korea, the findings point to a change of around 20 percent due to double-cropping in the NCP.

Ho explains, “The period of temporary desertification from double-cropping, between the first harvest and the time when the second crop begins to sprout, happens to coincide with South Korea’s rainy season, and it‘s intensifying the rainfall patterns.” He adds, “This is the first time observation data have been used to demonstrate the influence that changes in agricultural activity are having on summer climate change in Northeast Asia and to show the mechanism,” he added.

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