Levels of carbon dioxide in the atmosphere soared by a record amount in 2024, reaching a new high of 424 parts per million, according to the World Meteorological Organization (WMO). This marks the largest annual increase since modern measurements began in 1957, deepening concerns about the climate crisis.
The surge was driven by continued fossil fuel burning, despite global pledges to transition away from coal, oil and gas, as well as an upsurge in wildfires exacerbated by hotter and drier conditions. Wildfire emissions in the Americas reached historic levels in 2024, which was the hottest year on record.
Scientists are particularly worried that natural carbon sinks—oceans and forests that absorb about half of all CO2 emissions—may be weakening due to global heating. Warmer oceans absorb less CO2, while hotter, drier conditions and more wildfires reduce plant growth. Researchers observed an “unprecedented failure of the land sink” in 2023 and 2024, raising fears of a vicious cycle that could accelerate warming.
Dr Oksana Tarasova, a WMO senior scientific officer, warned that if terrestrial and ocean sinks become less effective, more CO2 will remain in the atmosphere, accelerating global warming. She stressed the need for sustained greenhouse gas monitoring to understand these feedback loops.
The WMO also reported that atmospheric concentrations of methane and nitrous oxide rose to record levels in 2024. Methane emissions come from natural sources and human activities like fossil fuel extraction and livestock, while nitrous oxide is linked to fertiliser overuse and industrial processes. The findings come ahead of the COP30 climate summit in Brazil, where nations will seek to ramp up climate action.
