An “unprecedented amount of heat” trapped in the atmosphere due to GHG record levels (WMO / K. Barrett)

“Levels of long-lived greenhouse gases in the atmosphere [especially the most abundant: carbon dioxide, methane, and nitrous oxide] are at record levels. GHGs are trapping an unprecedented amount of heat in the atmosphere,” said WMO Deputy Secretary-General, Ko Barrett, during the presentation of the WMO annual GHG Bulletin for 2025 on 27 October 2026.

About half of the total CO2 emitted each year remains in the atmosphere and the rest is absorbed by land ecosystems and oceans, she stressed. Yet, since the 1960s, growth rates of CO2 have tripled. The past 11 years have been the warmest on record, and this trend is set to continue.

According to the Bulletin, the globally averaged surface concentration of CO2 in 2025 was 426.8 parts per million (ppm), or 153% of the 1750 pre-industrial…