CO2 Levels Surged To Record High In 2024 With Largest-Ever Annual Increase, WMO Warns
As per the report, the record spike in CO2 is attributed to a combination of factors, which include human emissions, wildfires, and weakening carbon sinks.
Published : October 16, 2025 at 6:13 PM IST
Hyderabad: Atmospheric levels of heat-trapping carbon dioxide (CO2) soared to a new record high in 2024, recording the largest annual increase since modern measurements began in 1957, according to the latest Greenhouse Gas Bulletin released by the World Meteorological Organisation (WMO).
The alarming jump commits the planet to more long-term temperature rise and has prompted urgent calls for accelerated emissions reduction ahead of the upcoming UN Climate Change Conference (COP30) in Brazil.
The WMO bulletin revealed that the global average concentration of CO2 surged by 3.5 parts per million (ppm) from 2023 to 2024, reaching an overall concentration of 423.9 ppm. This single-year leap surpassed the average growth rate of the last decade (2011–2020), which was 2.4 ppm per year, and marks the highest annual increase ever recorded.
The global average CO2 concentration is now 52 per cent above pre-industrial levels (before 1750), reaching concentrations not seen for over 800,000 years, the report added.
"The heat trapped by CO2 and other greenhouse gases is turbo-charging our climate and leading to more extreme weather," said Ko Barrett, WMO Deputy Secretary-General. "Reducing emissions is therefore essential not just for our climate but also for our economic security and community well-being."
The record spike in CO2 is attributed to a combination of factors:
- Continued Human Emissions: Continued CO2 emissions from human activities, primarily the burning of fossil fuels (coal, oil, and gas)
- Wildfires: A major contribution from wildfire emissions, exacerbated by the exceptionally warm year of 2024 and a strong El Niño event, which typically reduces the ability of land ecosystems to uptake carbon.
- Weakening Carbon Sinks: Critically, the planet's natural carbon "sinks"—such as land ecosystems (like forests) and the ocean—showed a reduced ability to absorb CO2
Scientists are deeply concerned that this reduced absorption may signal the beginning of a "vicious climate cycle." Warmer ocean temperatures reduce the solubility of CO2, meaning the ocean absorbs less. Concurrently, hotter, drier conditions and phenomena like the strong El Niño in 2024 led to droughts and fires, further reducing the efficiency of land-based carbon sinks, such as the Amazon rainforest.
Oksana Tarasova, a WMO senior scientific officer, noted the concern: "There is concern that terrestrial and ocean CO2 sinks are becoming less effective, which will increase the amount of CO2 that stays in the atmosphere, thereby accelerating global warming."
Other greenhouse gases also set records
The two other most significant long-lived greenhouse gases, methane (CH4) and nitrous oxide (N2O), also climbed to record concentrations in 2024:
| Gas | 2024 Global Concentration | Increase Above Pre-Industrial Levels |
| Methane (CH4) | 1,942 parts per billion (ppb) | 166 per cent |
| Nitrous Oxide (N2O) | 338 parts per billion (ppb) | 25 per cent |
Methane, while having a shorter atmospheric lifetime than CO2, is a far more potent warming agent. Nitrous oxide, primarily driven by agricultural fertiliser use and other human activities, is the third most important long-lived greenhouse gas.
The WMO underscored that this record surge in gases—especially CO2, which remains in the atmosphere for centuries—reinforces the urgent need for drastically intensified action to achieve net-zero anthropogenic CO2 emissions. The bulletin provides a critical scientific basis ahead of the forthcoming UN Climate Change Conference, COP30, set to take place in Belém, Brazil, in November 2025.
