Carbon dioxide (CO2) levels in the atmosphere soared by a record amount to new highs in 2024
Posted on October, 16 2025
The message is clear: cut emissions fast, and protect and restore nature to keep these vital carbon sinks intact.
Carbon dioxide (CO₂) levels in the atmosphere have soared to new highs in 2024, committing the planet to more long-term temperature increase, according to a new report from the World Meteorological Organization (WMO).
In the the Greenhouse Gas Bulletin, published yesterday, WMO said continued emissions of CO₂ from human activities and an upsurge from wildfires were responsible, as well as reduced CO₂ absorption by “sinks” such as land ecosystems and the ocean – in what threatens to be a vicious climate cycle.
Concentrations of methane and nitrous oxide – the second and third most important long-lived greenhouse gases related to human activities – have also risen to record levels.
Growth rates of CO₂ have tripled since the 1960s, accelerating from an annual average increase of 0.8 ppm per year to 2.4 ppm per year in the decade from 2011 to 2020. From 2023 to 2024, the global average concentration of surged CO₂ by 3.5 ppm, the largest increase since modern measurements started in 1957.
Dr. Stephanie Roe, WWF Lead Climate and Energy Scientist, said: “This new record for atmospheric CO₂ is a stark and sobering milestone — a reminder that emissions are still rising, not falling. Nature has long been our silent partner: forests, grasslands, wetlands, and oceans absorb roughly half of human CO₂ emissions each year. But this critical service depends on healthy, functioning ecosystems.”
WMO released the annual Greenhouse Gas Bulletin to provide authoritative scientific information for the UN Climate Change conference in November. The COP30 meeting in Belém, Brazil, will seek to ramp up climate action.
“Pressures like deforestation, land conversion, degradation, and pollution are already eroding their health - and climate change is now compounding the damage. Warming impacts like heat stress, drought, wildfires, permafrost thaw, and ocean acidification weaken nature’s ability to absorb carbon. It is critical that we cut emissions sharply and fast, and we scale up conservation, restoration, and the resilience of nature to keep these carbon sinks intact,” said Roe.
WMO Deputy Secretary-General Ko Barrett said heat trapped by CO2 and other greenhouse gases is “turbo-charging our climate and leading to more extreme weather. Reducing emissions is therefore essential not just for our climate but also for our economic security and community well-being.”
Today’s CO₂ emissions to the atmosphere not only impact global climate today, but will do so for hundreds of years because of its long lifetime in the atmosphere.
Notes:
1. When the bulletin was first published in 2004, the annual average level of CO₂ was 377.1 ppm. In 2024 it was 423.9 ppm.
2. About half of the total CO₂ emitted each year remains in the atmosphere and the rest is absorbed by Earth’s land ecosystems and oceans. However, this storage is not permanent. As global temperature rises, the oceans absorb less CO₂ because of decreased solubility at higher temperatures, whilst land sinks are impacted on a number of ways, including the potential for more persistent drought.
3. The likely reason for the record growth between 2023 and 2024 was a large contribution from wildfire emissions and a reduced uptake of CO₂ by land and the ocean in 2024 – the warmest year on record, with a strong El Niño. During El Niño years, CO₂ levels tend to rise because the efficiency of land carbon sinks is reduced by drier vegetation and forest fires – as was the case with exceptional drought and fires in the Amazon and southern Africa in 2024.
4. Read the WMO report here.
5. See WWF’s COP30 Expectations Paper here.