UN Says Greenhouse Gases Reached Fresh Highs in 2025
WHO:
CBS News - The United Nations’ World Meteorological Organization (WMO) reported record atmospheric concentrations of carbon dioxide, methane and nitrous oxide.
CBS News - WMO Deputy Secretary-General Ko Barrett said, “Another year, another new record,” and said greenhouse gases were trapping unprecedented heat, providing energy for more extreme weather and risks to economies and societies.
CBS News - WMO senior scientific officer Oksana Tarasova said the 2025 carbon dioxide increase reflected recovering land carbon sinks and reduced fire emissions after the strong 2023/2024 El Niño.
Phys.org - The United Nations said greenhouse gas concentrations in the atmosphere reached new record highs in 2025, locking in climate impacts that will persist for centuries.
WHAT:
CBS News - The WMO bulletin measures greenhouse-gas concentrations in the atmosphere, not the amount of new emissions released each year.
CBS News - WMO Deputy Secretary-General Ko Barrett said carbon dioxide’s long lifetime means it will affect the global climate for decades and centuries.
Phys.org - A new WMO report said record concentrations of carbon dioxide and other major greenhouse gases are locking in further long-term warming.
CBS News - The WMO’s 22nd annual Greenhouse Gas Bulletin reported 2025 concentrations of carbon dioxide at 426.8 parts per million (ppm), methane at 1,948 parts per billion, and nitrous oxide at 339.1 parts per billion.
CBS News - Those concentrations were respectively 153%, 267% and 126% of pre-industrial levels before 1750.
CBS News - Carbon dioxide accounts for about 66% of the warming effect from the three main greenhouse gases; methane accounts for about 16% of the warming effect from long-lived greenhouse gases.
CBS News - Global average carbon dioxide concentration rose 2.8 ppm from 2024 to 2025, compared with a record 3.6 ppm increase from 2023 to 2024. The 2.8 ppm rise was above the decade’s average annual growth of 2.6 ppm and the 0.8 ppm rate in the 1960s.
CBS News - About half of annual carbon dioxide emissions remain in the atmosphere; land and oceans absorb the rest.
CBS News - About one-third of atmospheric methane emissions come from natural sources such as wetlands; anthropogenic sources include cattle, rice farming, landfills and biomass burning.
CBS News - Sulfur hexafluoride (SF6), used primarily as a spark suppressant in electricity distribution, has risen steadily over the past three decades. Hydrogen (H2) has also increased over the past decade, for reasons the bulletin said are unknown.
WHERE:
CBS News - The COP31 U.N. climate summit is scheduled to take place in Antalya, Turkey.
WHEN:
CBS News - The WMO said concentrations of all three main greenhouse gases reached unprecedented levels in 2025.
CBS News - The COP31 summit is scheduled for Nov. 9 to Nov. 20.
WHY:
CBS News - The WMO said rising greenhouse-gas concentrations would lead to further long-term increases in global temperature.
CBS News - Oksana Tarasova said fossil-fuel burning and the development of a powerful El Niño are expected to increase greenhouse-gas concentrations in 2026 by affecting land carbon sinks.
CBS News - Tarasova said the 2025 carbon dioxide rise was associated with recovering land carbon sinks and reduced fire emissions following the strong 2023/2024 El Niño.
CBS News - Tarasova said fossil-fuel burning continued to add substantial carbon to the atmosphere and warned that a powerful El Niño could affect land carbon sinks and increase concentrations further.
(UPDATED October 27, 2026 18:01 UTC)
The World Meteorological Organization says atmospheric concentrations of carbon dioxide, methane and nitrous oxide hit record highs in 2025, locking in further warming that can persist for centuries. Carbon dioxide reached 426.8 parts per million, rising 2.8 parts per million from the previous year, as fossil-fuel use continued to add substantial carbon to the atmosphere. The WMO says concentrations could rise further in 2026 as fossil-fuel burning continues and a powerful El Niño affects the land’s ability to absorb carbon.
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(UPDATED October 27, 2026 15:07 UTC)
The World Meteorological Organization says concentrations of carbon dioxide, methane and nitrous oxide reached record highs in 2025, locking in climate impacts that will persist for centuries. Carbon dioxide reached 426.8 parts per million, with the increase linked to recovering land carbon sinks and reduced fire emissions after a strong El Niño, while fossil-fuel burning continued to add substantial carbon. The WMO warns that greenhouse gases are trapping unprecedented heat and fueling risks from extreme weather to economies and societies.