WMO REPORTS RECORD GREENHOUSE GAS LEVELS IN 2025

The World Meteorological Organisation said global concentrations of the three main greenhouse gases reached record highs in 2025. Its annual Greenhouse Gas Bulletin put 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 WMO said the accumulated gases would drive further long-term warming. “Greenhouse gases are trapping an unprecedented amount of heat in the atmosphere, providing energy for more extreme weather and associated risks to our economies and societies,” said WMO Deputy Secretary-General Ko Barrett.

The bulletin measures concentrations already in the atmosphere, rather than the amount newly emitted each year. The WMO put the 2025 concentrations of carbon dioxide, methane and nitrous oxide at 53%, 167% and 26% above pre-industrial levels respectively. It said carbon dioxide accounts for about 66% of the warming effect of the three gases, while roughly half of annual carbon dioxide emissions remain in the atmosphere. Carbon dioxide concentrations rose by 2.8 parts per million from 2024 to 2025, compared with a 3.6 parts per million rise the previous year, according to the WMO.

WMO scientific officer Oksana Tarasova attributed the slower rise to recovering land carbon sinks and lower fire emissions after the 2023–24 El Niño. The WMO also called for closer attention to atmospheric hydrogen and sulphur hexafluoride as more countries change their energy systems. It reported a 5.3% increase in hydrogen concentrations from 2010 to 2024 and said sulphur hexafluoride levels had risen steadily over three decades. The bulletin precedes the COP31 UN climate summit in Antalya, Turkey, scheduled for 9 to 20 November.