South Korea's Carbon Dioxide Concentration Exceeds the Global Average

[The Financial News, Jeju = Lee Bomi] Last year, South Korea's atmospheric carbon dioxide concentration hit a new record high. Major greenhouse gases, including methane, nitrous oxide and sulfur hexafluoride, also reached all-time highs. While the rate of increase matched the global average, concentrations remained higher, making the buildup of greenhouse-gas burdens increasingly clear.
According to the 2025 Global Atmosphere Watch Report released on the 29th by the National Institute of Meteorological Sciences under the Korea Meteorological Administration (KMA), South Korea's background carbon dioxide concentration rose to 432.7 ppm, up 3.2 ppm from 429.5 ppm a year earlier. It was the highest level since observations began in 1999 and the second-largest increase in the past 10 years, from 2015 to 2024. The figure was 7.1 ppm higher than the global average of 425.6 ppm. By monitoring site, Anmyeondo recorded 434.0 ppm, Gosan, Jeju 432.4 ppm, and Ulleungdo 431.7 ppm, all setting new records.
Since 2000, South Korea's carbon dioxide concentration has risen by an average of 2.5 ppm a year. Over the past decade, the pace of increase has averaged 2.6 ppm annually, in line with the global average. As absolute concentrations remain higher while the growth rate stays the same, the domestic burden of greenhouse gases is clearly accumulating in a structural way. Analysis from Japan's Greenhouse Gases Observing Satellite (GOSAT) also showed the same upward trend as ground-based observations, supporting the reliability of the data.
Kim Sang-baek, head of the Global Atmospheric Monitoring Research Division at the National Institute of Meteorological Sciences, explained, "It is a complex structure that is difficult to explain with a single factor, and local emissions and atmospheric circulation may have worked together."
Other major greenhouse gases also set new records across the board. Methane rose by 2 ppb from the previous year to 2,023 ppb, though the increase slowed compared with the 10-year average gain of 10 ppb a year. Nitrous oxide reached 340.6 ppb and sulfur hexafluoride 12.5 ppt, both above the global average. Carbon dioxide remains in the atmosphere for more than 100 years and accumulates over the long term, while methane lasts only about nine years but has a stronger short-term warming effect. Kim said, "Because methane's atmospheric lifetime is much shorter than carbon dioxide's, policy-driven reductions can appear relatively quickly," adding that the agency is closely analyzing the reasons for the slowdown in its growth rate.
By contrast, chlorofluorocarbons, which destroy stratospheric ozone, continued to decline thanks to international regulation under the 1989 Montreal Protocol on Substances that Deplete the Ozone Layer (Montreal Protocol). Fine dust and aerosols also showed a downward trend, and the acidity of precipitation eased to 5.2.
The KMA monitors greenhouse gases through the Global Atmosphere Watch Programme (GAW) at sites including Anmyeondo, Gosan, Jeju, Ulleungdo, Liancourt Rocks and Pohang. The report has been published annually since 2001, and this year its release was moved up from June to April. Kang Hyun-seok, Director-General of the National Institute of Meteorological Sciences, said, "We will support climate-crisis response policies by providing timely and accurate Global Atmosphere Watch information," adding, "We will strengthen our capabilities to trace the origins of climate-change-causing substances and analyze their impacts and effects."
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