426.8 ppm: the global CO2 concentration reported for 2025
Atmospheric concentrations reached new records for CO2, methane and nitrous oxide, WMO reports. CO2 rose 2.8 ppm to a 2025 global average of 426.8 ppm.
What happened
WMO’s October 27 bulletin puts the globally averaged surface concentration of carbon dioxide in 2025 at 426.8 parts per million. Methane and nitrous oxide also reached records, according to the organisation.
These measurements describe gases accumulating in the atmosphere, rather than the amount emitted in a single year. WMO reports a 2.8 ppm increase in carbon dioxide between 2024 and 2025 and highlights the gas’s long-lasting effect on the climate.
Sources and method
Greenhouse gas levels once again reach record high ↗
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