Overview
- Global average CO2 reached 423.9 ppm in 2024, rising by 3.5 ppm from 2023 for the largest year-on-year increase since 1957.
- Methane and nitrous oxide also set records in 2024, at about 1,942 ppb and 338.0 ppb respectively.
- The WMO attributes the spike to ongoing human emissions, exceptional wildfire emissions, and reduced absorption by land and ocean sinks during a strong El Niño and severe drought in regions including the Amazon and southern Africa.
- WMO scientist Oksana Tarasova warns that weakening terrestrial and ocean sinks mean more CO2 will remain in the atmosphere, accelerating warming.
- Released ahead of COP30 in Belém, the WMO Greenhouse Gas Bulletin urges expanded, sustained monitoring to track feedbacks and support stronger policy action.