WMO reports record greenhouse gas concentrations in 2025

The World Meteorological Organization says atmospheric concentrations of carbon dioxide, methane and nitrous oxide all reached record levels in 2025, adding to the buildup of heat-trapping gases in the atmosphere. The WMO’s annual Greenhouse Gas Bulletin measured global-average carbon dioxide at 426.8 parts per million, methane at 1,948 parts per billion and nitrous oxide at 339.1 parts per billion. The figures describe accumulated atmospheric concentrations, not the amount of emissions released during 2025. Carbon dioxide was 53% above its estimated preindustrial level, the bulletin said. Methane stood at 267% of its preindustrial level and nitrous oxide at 126%. The WMO’s measurements reflect a continuing rise in the three gases, which trap heat and contribute to long-term warming. Carbon dioxide concentration increased by 2.8 parts per million between 2024 and 2025. That was above the average annual increase of 2.6 parts per million over the previous decade, but below the 3.6 parts per million rise from 2023 to 2024, according to the bulletin. Oksana Tarasova, a WMO senior scientific officer, attributed the smaller increase compared with the prior year partly to recovering...