Carbon dioxide levels in atmosphere climb at record rate to new highs in 2024

Carbon dioxide levels in the atmosphere rose by a record amount to new highs in 2024, locking in yet more long-term global warming, UN experts have warned.

The annual update by the World Meteorological Organisation (WMO) also highlighted that other major greenhouse gases methane and nitrous oxides have also risen to new record highs in the last year.

The bulletin said continued carbon dioxide emissions from human activities and an upsurge in wildfires were responsible for the record increase.

The Earth’s oceans and lands also absorbed less carbon dioxide, in what could be a vicious climate cycle, as their ability to take in and store the greenhouse gas weakens with rising temperatures.

WMO deputy secretary-general Ko Barrett said: “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.”

The levels of carbon dioxide in the atmosphere have been growing at an increasingly fast pace, trebling from an annual average increase of 0.8 parts per million (ppm) a year in the 1960s to 2.4 ppm a year in the decade from 2011-2020.

Levels of carbon dioxide in the atmosphere surged by 3.5ppm between 2023 and 2024, the largest increase since modern measurements started in 1957, the WMO said.

Carbon dioxide levels have now reached 423 ppm, up from 377 ppm, when the annual greenhouse gas bulletin was first published in 2004, and 52% above pre-industrial levels of 278 ppm, figures from the WMO show.

Carbon dioxide emissions currently being released affect the global climate today but will also continue to do so for hundreds of years, because of the greenhouse gas’s long lifetime in the atmosphere.

The UN’s meteorological body said about half the carbon dioxide emitted each year is absorbed by forests and other land ecosystems and oceans.

But as global temperatures rise, the oceans absorb less CO2 because it dissolves less effectively in the water at higher temperatures, while land takes in less carbon for a range of reasons including greater drought.

The record increase in carbon dioxide in the atmosphere in 2024 is likely due to a large contribution from wildfire emissions and reduced uptake by land and ocean “carbon sinks” as the world faced its hottest year on record, with a strong El Nino weather pattern.

El Nino years tend to reduce the storage of carbon dioxide in land sinks due to drier vegetation and forest fires, which were seen in droughts and fires in the Amazon and southern Africa in 2024, the WMO said.

Oksana Tarasova, a WMO senior scientific officer, said: “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.

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

Alec Hutchings, WWF’s chief climate adviser, said: “The sharp rise in carbon dioxide in the atmosphere last year is huge cause for concern.

“Our planet’s land and oceans have absorbed about half of our emissions so far, but we continue to pile pressure on these environments, and they cannot keep up.

“We must cut climate emissions, but we must also urgently protect our natural systems that are our greatest ally in tackling climate change. “