Overview

• Global averages in 2024 reached about 424 ppm CO2, 1,942 ppb methane, and 338 ppb nitrous oxide, according to the WMO’s 21st Greenhouse Gas Bulletin.
• The increase in CO2 from 2023 to 2024 was roughly 3.5 ppm, the largest one-year rise since modern measurements began in 1957.
• WMO officials say CO2 growth rates have tripled since the 1960s, with continued fossil fuel use and widespread wildfires feeding a “vicious climate cycle.”
• The agency voiced significant concern that natural carbon sinks are weakening, reducing the share of emissions absorbed by land and oceans and heightening warming risks.
• The bulletin arrives ahead of COP30 in Brazil and before a separate UN assessment of emissions due next month, as the WMO notes 2024 was the warmest year on record.