Biggest ever rise in atmospheric CO2 recorded
In 2024, CO2 levels hit record highs, accelerating climate change and extreme weather, according to the WMO. Urgent action on emissions is essential.
Carbon dioxide (CO2) levels in the atmosphere soared to record levels in 2024, committing the planet to more long-term temperature increase, according to a new report from the World Meteorological Organization (WMO).
The WMO Greenhouse Gas Bulletin said continued emissions of CO2 from human activities and from wildfires, and reduced CO2 absorption by “sinks” such as land ecosystems and the ocean were responsible for this spike.
From 2023 to 2024, the global average concentration of CO2 surged by 3.5 ppm, the largest increase since modern measurements started in 1957, WMO added.
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.
“The 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,” said WMO deputy secretary-general Ko Barrett in a statement on Wednesday.
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.
WMO released the annual greenhouse gas bulletin to provide authoritative scientific information for the UN Climate Change conference in November. The COP 30 meeting in Belém, Brazil, will seek to ramp up climate action.
“Sustaining and expanding greenhouse gas monitoring are critical to support such efforts,” said Oksana Tarasova, coordinator of the Greenhouse Gas Bulletin, which is one of WMO’s flagship scientific reports and is now in its 21st issue.
“The pre-industrial level of 278.3 ppm represented a balance of fluxes among the atmosphere, the oceans and the land biosphere. The globally averaged CO2 concentration in 2024 was 423.9±0.2 ppm (Figure 5a), 152% of the pre-industrial level,” the bulletin said.
The global temperature in 2024 was the highest recorded in the observational record dating back to 1850, breaking the record previously set in 2023. For the first time, it passed the significant 1.5 °C mark relative to the pre-industrial period, mainly a result of El Nino.
El Niño is the warm phase of the El Niño–Southern Oscillation (ENSO) weather pattern, often associated with abnormal weather, such as strong storms in some regions and droughts or flooding in others. These changes alter regional temperature and precipitation patterns, which in turn influence photosynthetic CO2 uptake, respiratory CO2 release and the frequency and magnitude of fires, WMO said.
The oceans may have contributed to a small fraction of the additional carbon dioxide in 2024, as record-breaking sea-surface temperatures in 2023 persisted into 2024. However, the majority of the 2024 anomaly arose from decreased net ecosystem carbon uptakes and increased fire emissions.
The Amazon and Southern Africa experienced record-high fire activities in 2023–2024, as drought conditions were severe in several land regions. “There is a significant concern that terrestrial and ocean CO2 sinks are becoming less effective, which will increase the fraction of anthropogenic CO2 that stays in the atmosphere, thereby accelerating global warming. Sustaining and enhancing greenhouse gas monitoring is even more critical now to understand these feedbacks and to provide the information needed to inform and monitor climate action,” the bulletin said.
