Climate change is causing the heatwave period on the Korean Peninsula to lengthen, and it is expected that heatwaves may continue from May to September in the future.
Recently, the Korea Meteorological Administration published a "heatwave white paper" detailing the causes of heatwaves, past cases, and future projections. While the Korea Meteorological Administration has previously released white papers on monsoons, typhoons, and El Niño (the phenomenon of elevated sea surface temperatures in the tropical eastern Pacific), this is the first white paper focused on heatwaves. Lee Myung-in, the head of the Heatwave Research Center at the Ulsan National Institute of Science and Technology, is the main author of the white paper.
According to the white paper, the onset of heatwaves is occurring earlier, and their duration is also increasing. In the 1990s, heatwaves began in early July, but in the 2010s, this was advanced to late June. The latest occurrence of heatwaves shows little difference; overall, there is a trend of lengthening heatwave durations.
In particular, the number of tropical nights (when the minimum temperature remains above 25 degrees Celsius) recorded last summer was 20.1 days, setting a record high. Although heatwaves and tropical nights were severe in 1994 and 2018, the year 2023 surpassed those years, making the effects of climate change palpable.
It is also expected that heatwaves will intensify according to future climate change scenarios. If greenhouse gas reductions are not implemented (the SSP5-8.5 scenario), it is highly likely that the heatwaves currently appearing from July to September on the Korean Peninsula will extend from May to September. The duration of these heatwaves could also increase from the current average of 4.4 days to a maximum of 17.4 days, according to warnings.
The researchers noted, "Whether or not to respond to climate change will significantly affect the intensity and duration of heatwaves," emphasizing that reducing greenhouse gas emissions is essential. If the average global temperature rises more than 3 degrees compared to the period prior to industrialization, it is also projected that extreme heatwaves like those of the summer of 2018 will become the norm.
Currently, the concentration of carbon dioxide in the atmosphere is 420 ppm, but if efforts to reduce greenhouse gases are insufficient, it is projected to increase to as much as 1,089 ppm by 2100. As a result, there is a high likelihood that East Asia, including the Korean Peninsula, will experience unprecedented levels of heatwaves.
The researchers emphasized, "If greenhouse gas emissions are not reduced, heatwaves will intensify by the end of the century," stating that carbon emission reductions are a key measure to mitigate the climate crisis.