Carbon dioxide levels increase by record amount to new highs in 2024: WMO

GENEVA, Oct. 16 (Xinhua) -- Carbon dioxide (CO2) levels in the atmosphere soared by a record amount to new highs in 2024, committing the planet to more long-term temperature increase, according to a report from the World Meteorological Organization (WMO).

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, said the WMO Greenhouse Gas Bulletin released Thursday.

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 CO2 surged by 3.5 ppm, the largest increase since modern measurements started in 1957, it 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," said WMO Deputy Secretary-General Ko Barrett.

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, according to the bulletin.

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, while land sinks are impacted in a number of ways, including the potential for more persistent drought.

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 Nino.

During El Nino 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.

"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," said Oksana Tarasova, a WMO senior scientific officer.

The current CO2 emissions to the atmosphere will also impact the global climate for hundreds of years because of its long lifetime in the atmosphere.

WMO released the annual greenhouse gas bulletin to provide authoritative scientific information for the United Nations Climate Change conference in November. The COP 30 meeting in Belem, 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. ■