GENEVA, Oct. 27 -- Levels of carbon dioxide (CO2) and other major greenhouse gases in the atmosphere reached unprecedented highs in 2025, locking in more long-term temperature increases for the planet, according to a bulletin from the World Meteorological Organization (WMO) released on Tuesday.

The global average surface concentration of CO2 in 2025 was 53 percent above the 1750 pre-industrial baseline, the WMO Greenhouse Gas Bulletin showed. Concentrations of methane and nitrous oxide -- the second and third most important long-lived greenhouse gases related to human activities -- also rose to a new record, with respective increases of 167 percent and 26 percent.

"Another year, another new record," said WMO Deputy Secretary-General Ko ...