Antalya:Levels of carbon dioxide (CO2) and other major greenhouse gases in the atmosphere reached unprecedented highs in 2025, locking in more long-term temperature increases for the planet, according to a new report from the World Meteorological Organization (WMO).

According to Wam, the WMO Greenhouse Gas Bulletin reported that the globally averaged surface concentration of CO2 in 2025 was 426.8 parts per million, or 153% of the 1750 pre-industrial baseline. Concentrations of methane and nitrous oxide—the second and third most important long-lived greenhouse gases related to human activities—also rose to a new record.

WMO Deputy Secretary-General Ko Barrett commented on the findings, stating that greenhouse gases are trapping an unprecedented amount of heat in the atmosphere, which contributes to more extreme weather and associated risks to economies and societies. Barrett noted that the past 11 years have been the warmest on record, and this trend is expected to continue. CO2, in particular, has a very long life-time and will affect the global climate for decades and even centuries.

WMO releases the Bulletin, one of its flagship annual publications, to provide authoritative scientific information for negotiators at the UN Climate conference. The COP 31 meeting in Antalya, Türkiye, from 9-20 November 2026 is aimed at turning climate commitments into concrete actions.

Methane, accounting for about 16% of the warming effect on our climate by long-lived greenhouse gases, has a much shorter lifetime than CO2. Approximately 35% of methane emissions are from natural sources like wetlands, which are climate-sensitive, while about 65% comes from anthropogenic sources such as cattle, rice farming, fossil fuel exploitation, landfills, and biomass burning. The globally averaged methane concentration in 2025 was 1948 parts per billion (ppb), or 267% of the 1750 level.

Nitrous oxide, the third most important long-lived greenhouse gas, originates from both natural sources and human activities, including biomass burning, fertilizer use, and various industrial processes. The globally averaged concentration of N2O reached 339.1 ppb in 2025, 126% above the 1750 level.