Greenhouse gas levels hit record highs in 2025, UN says
WMO bulletin finds carbon dioxide, methane and nitrous oxide all at unprecedented concentrations
Concentrations of the three main greenhouse gases rose to record highs in 2025, locking in climate impacts that will persist for decades and centuries, the UN's weather and climate agency said. The World Meteorological Organization's 22nd annual Greenhouse Gas Bulletin found carbon dioxide at 426.8 parts per million, methane at 1,948 parts per billion and nitrous oxide at 339.1 parts per billion.