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| A rescue operation is underway at a flooded underpass in Cheongju, North Chungcheong Province, in this July 15 file photo provided by the Korea National Fire Agency. AP-Yonhap |
By Holly Chik
Consecutive extreme rainfall and heat waves are likely to become more frequent in the future around the world given the ongoing trajectory of global warming, according to a recent study.
The scientific team in Korea and the United States found that global warming was behind the increased frequency of extreme precipitation in their analysis of data from 1980 to 2020.
The researchers from Chonnam National University in Gwangju, Pohang University of Science and Technology, the Institute for Basic Science in Busan, as well as the University of Washington and the University of Hawaii at Manoa in the United States, published their findings in the peer-reviewed journal Nature last week.
First author Ham Yoo-geun, a professor leading the ocean and climate science laboratory at Chonnam National University, said East Asia, the eastern U.S. and Canada are expected to see abrupt shifts in weather within short time scales.
"It is more problematic because two extremes happen together in the same place. One day we experience heavy rainfall events, but we are experiencing heat waves within a few days," he said.
"During the summer season, once there's no rainfall, it is directly connected to heat waves. Because there are no clouds, the incoming solar radiation would be increasing, leading to heat waves."
While previous studies have shown that global warming would intensify rainfall variability and extremes in the long term, the new analysis using artificial intelligence found that "the impact of global warming on daily hydrological fluctuations has already emerged."
Ham said the study showed "a clear connection between global warming and much more frequent extreme rainfall events."
"Everybody was just guessing that these kinds of extreme rainfall events these days in summer are related to global warming. But there was no scientific evidence," he said.
"We found the scientific evidence and we can finally say that this kind of change in the frequency of extreme rainfall is due to global warming."
The team applied a deep learning model that quantifies the relationship between the intensity of global warming and global daily rain patterns to data obtained from satellite-based rain observations.
Their findings showed that since 2015, the daily rain pattern for more than half of all days has deviated from its natural variability due to influence by human-induced global warming.
In Korea, Ham said comparing summers from 1980 to 2020, there was a marked jump in days with very little or no rain from June to August three years ago, as well as a slight increase in days with heavy rain.
He said as the weather swings between extremes, authorities and the public should be prepared for both phenomena.
"It becomes more complex to prepare for global warming," he said. "It's not just the increase of temperature, but also you have to prepare for other extremes that are going to happen."
Holly Chik is a science reporter with the South China Morning Post. She is currently based in Seoul, reporting for both The Korea Times and the South China Morning Post under an exchange program.
