2024 Saw Higher Levels Of Carbon Dioxide In The Atmosphere Than Ever Before

Overall, we’re basically running out of planetary health measures to break at this point. And yet, news from the World Meteorological Organization (WMO) this week shows that we’ve done it again, with 2024 seeing the Earth’s atmosphere filled with record high levels of carbon dioxide.

“The latest analysis of observations from the WMO Global Atmosphere Watch (GAW) in situ observational network shows that the globally averaged surface concentrations for carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O) reached unprecedented highs in 2024, with CO₂ at 423.9±0.2 ppm, CH₄ at 1942±2 ppb and N₂O at 338.0±0.1 ppb,” confirms a new press release from the body – record levels for all three of the most important long-lived greenhouse gases related to human activity. 

“These values constitute, respectively, increases of 52 percent, 166 percent and 25 percent above pre-industrial (before 1750) levels,” the WMO adds.

That makes this news a double-hitter: not only is it a record high of the raw amount of these greenhouse gases in our atmosphere, but it’s also the greatest year-on-year increase in CO₂ since records began. 

That jump is likely due to a combination of reasons. El Niño years – of which 2024 was one – often see a rise in CO₂ levels, as drier conditions lead to more forest fires and less CO₂ being absorbed by and ecosystems. But even with those caveats, 2024 was an outler: the latest data shows last year’s wildfires burned through an area of land twice the size of Alaska, releasing more than eight billion tonnes of CO₂ in the process – and almost 10 percent more than the yearly average over the past two decades. 

More worrying, however, is where that added CO₂ is going – or, rather, not going. Normally, some 30 percent of all carbon dioxide emissions are absorbed by the ocean, with various other features like forests, soils, and plants making up another 20 percent. But it seems like these natural carbon sinks may be reaching their limit: in 2023, terrestrial sinks absorbed almost no carbon at all, and with rising temperatures, the oceans are less and less able to take in what we’ve been putting out.

The result? A catastrophic feedback loop, with rising temperatures leading to more atmospheric CO₂, which in turn contribute to rising temperatures.

“Terrestrial and ocean CO₂ sinks […] becoming less effective […] will increase the amount of CO₂ that stays in the atmosphere, thereby accelerating global warming,” confirmed Oksana Tarasova, a WMO senior scientific officer and coordinator of the WMO’s Greenhouse Gas Bulletin, in a statement accompanying the news. 

“Sustained and strengthened greenhouse gas monitoring is critical to understanding these loops,” she added.

While carbon dioxide isn’t the only greenhouse gas that’s increased, the jumps in methane and nitrous oxide levels – while still important to consider – are less pressing right now. Methane has an atmospheric lifetime of around a decade, compared with CO₂’s centuries – albeit the gas is a much more efficient greenhouse gas for its comparatively short time on Earth. Nitrous oxide, meanwhile, is no laughing matter – but currently only comprises around six percent of all greenhouse gas emissions, compared to around 80 percent for CO₂. 

And frankly, just the fact that the latest CO₂ levels are being reported in parts per million, versus the other two in parts per billion, should clue you in to how urgent this problem is.

“The heat trapped by CO₂ and other greenhouse gases is turbo-charging our climate and leading to more extreme weather,” warned WMO Deputy Secretary-General Ko Barrett. “Reducing emissions is therefore essential not just for our climate but also for our economic security and community well-being.”

The WMO Greenhouse Gas Bulletin No 21, where these results are published, can be found here.