Atmospheric carbon dioxide rose by 3.5 parts per million between 2023 and 2024—the largest annual jump since records began in 1957—according to a new bulletin from the World Meteorological Organization.
This unprecedented rise is pushing levels to heights not seen in over 800,000 years, and intensifying extreme weather phenomena globally.
The report attributes the CO₂ spike primarily to burning fossil fuels, widespread wildfires, and increased emissions from degrading natural carbon sinks like forests and oceans.
Crucially, the Amazon rainforest—traditionally a major carbon absorber—is under stress from drought and heat, weakening its capacity to absorb CO₂ and risking reversal into a net carbon emitter.
Other greenhouse gases, including methane and nitrous oxide, also reached record levels in the same period.
Scientists warn this trend undermines prospects of meeting the Paris Agreement’s 1.5 °C threshold. The Earth now appears more likely to warm closer to 3 °C under current trajectories.
WMO officials cautioned that the buildup of greenhouse gases is “turbo-charging” the climate, increasing the frequency and severity of extreme heat, storms, droughts, and floods.
They also flagged a growing risk of tipping points: if vital ecosystems such as the Amazon shift from absorbing CO₂ to releasing it, the climate system could flip into self-reinforcing warming.
The WMO is urging immediate and stronger global climate policies, calling for steeper emissions cuts, more aggressive transitions to clean energy, and protection and restoration of natural carbon sinks.
At this critical juncture, scientists emphasize that delaying action will make the cost and difficulty of mitigation far greater—and the risks to human and ecological systems much more severe.
