The World Meteorological Organization said atmospheric concentrations of carbon dioxide, methane and nitrous oxide reached new record highs in 2025, with CO2 averaging 426.8 parts per million.
The World Meteorological Organization reported on October 27 that globally averaged atmospheric concentrations of the three major long-lived greenhouse gases reached record levels in 2025.
Carbon dioxide averaged 426.8 parts per million, 153 percent of the 1750 pre-industrial baseline. Methane stood at 1948 parts per billion, or 267 percent of pre-industrial levels, and nitrous oxide at 339.1 parts per billion, 126 percent above 1750.
The 2.8 ppm rise in CO2 from 2024 to 2025 exceeded the recent decadal average of 2.4 ppm but was below the exceptional surge of the prior El Niño year. WMO senior scientific officer Oksana Tarasova attributed the moderation to recovery of land carbon sinks and reduced fire emissions after the 2023-2024 El Niño.
The organization’s Greenhouse Gas Bulletin confirms the figures against its Global Atmosphere Watch network. Reuters independently reported the same record levels and the 2.8 ppm increase. The organization has not claimed any decline in the long-term trajectory.
The findings will inform negotiators at COP31 in Antalya, Turkey, from November 9 to 20. Deputy Secretary-General Ko Barrett said the gases trap an unprecedented amount of heat, and CO2’s long lifetime will affect the climate for decades and centuries. A powerful El Niño developing in 2026 is expected to drive a further rise.
People Sentiments Public Mood: Negative
- Ko Barrett: Another year, another new record.
- Oksana Tarasova: A 2.8 ppm annual increase is still a substantial addition of carbon.