Atmospheric CO2 Levels Rising Faster Than IPCC's 1.5°C Pathways Allow

Record CO2 increases in 2024 highlight challenges to limiting global warming as natural carbon sinks weaken and emissions remain high.

Atmospheric CO2 concentrations rose by 3.58 parts per million (ppm) in 2024, the fastest annual increase recorded at Mauna Loa since measurements began in 1958.
The observed rise exceeded Met Office forecasts and far outpaced IPCC-compatible pathways to limit global warming to 1.5°C, which require CO2 increases to slow to 1.8 ppm per year this decade.
Weakened natural carbon sinks, exacerbated by El Niño-driven heat and widespread wildfires, reduced the ability of forests and soils to absorb CO2 in 2024.
Global CO2 emissions reached record highs in 2024 due to continued fossil fuel use and deforestation, further contributing to atmospheric CO2 buildup.
While a shift to La Niña conditions in 2025 may temporarily slow the rise in CO2 levels, significant and urgent emissions reductions are needed to meet climate targets.