Overview

• Global average CO2 rose by 3.5 ppm in 2024 compared with 2023, the largest year‑to‑year increase since systematic measurements began in 1957.
• Concentrations of the three main greenhouse gases—carbon dioxide, methane and nitrous oxide—each reached new records, according to the WMO’s 21st annual bulletin.
• The agency links the surge to ongoing human emissions, increased wildfires and weakened absorption by natural sinks such as terrestrial ecosystems and oceans.
• Last year was the warmest on record, surpassing 2023, with heat trapped by greenhouse gases intensifying extreme weather, the WMO notes.
• The findings land ahead of COP30, scheduled for November 10–21 in Belém, Brazil, as WMO’s Ko Barrett calls for emissions cuts to protect climate, economic security and public well‑being.