Overview

• Atmospheric CO2 rose by 3.5 ppm from 2023 to 2024 to reach 423.9 ppm, marking the fastest annual increase in the instrumental record.
• Methane and nitrous oxide concentrations also hit new highs, the WMO reported in its latest greenhouse gas bulletin.
• The WMO estimates carbon dioxide is responsible for about 64% of observed warming, emphasizing its dominant contribution.
• Drivers cited include sustained fossil‑fuel combustion, El Niño‑linked drought and fires, and weakening carbon uptake by oceans and land.
• The assessment warns progress toward the Paris targets is at risk, with 2024 averaging about 1.55°C above pre‑industrial levels.