Zürcher Nachrichten - CO2 in the atmosphere up by record amount in 2024: UN

Levels of the three main greenhouse gases -- the climate-warming CO2, methane and nitrous oxide -- all increased yet again in 2024, with each setting new record highs, the UN's weather and climate agency said.

The World Meteorological Organization said the increase in CO2 levels in the atmosphere from 2023 to 2024 marked the biggest one-year jump since records began in 1957.

Wednesday's report, which comes ahead of the November 10-21 COP30 UN climate summit in Belem, Brazil, focused exclusively on concentrations of greenhouse gases in the atmosphere.

A separate UN report, out next month, will detail shifts in emissions of the gases, but those numbers are also expected to rise, as they have every year with the world continuing to burn more oil, gas and coal.

This defies commitments made under the 2015 Paris Agreement to cap global warming at "well below" 2C above average levels measured between 1850 and 1900 -- and 1.5C if possible.

The WMO voiced "significant concern" that land and oceans were becoming unable to soak up CO2, leaving the powerful greenhouse gas in the atmosphere.

"The heat trapped by CO2 and other greenhouse gases is turbo-charging our climate and leading to more extreme weather," said 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."

Last year was also the warmest year ever recorded, beating the previous high in 2023, the WMO recalled.

"The levels of the three most abundant long-lived greenhouse gases -- carbon dioxide, methane and nitrous oxide -- reached new records in 2024," the WMO said in its 21st annual Greenhouse Gas Bulletin.

In 2024, CO2 concentrations were at 424 parts per million (ppm), methane at 1,942 parts per billion, and nitrous oxide at 338 parts per billion.

That marks hikes of 152 percent, 266 percent and 125 percent respectively since pre-industrial levels before 1750.

Of the three major greenhouse gases, CO2 accounts for about 66 percent of the warming effect on the climate.

When the Greenhouse Gas Bulletin was first published in 2004, the figure stood at 377 ppm.

The 3.5 ppm increase from 2023 to 2024 was "the largest one-year increase since modern measurements began in 1957", the WMO said.

H.Roth--NZN