Concentrations of greenhouse gases, responsible for climate change, have broken records in 2022, a trend which is not likely to be reversed, the UN warned on Wednesday, calling for an urgent reduction in consumption of fossil fuels.
For the first time, in 2022, global average concentrations of carbon dioxide (CO2), the most important greenhouse gas, exceeded pre-industrial values by 50%.
They continued to increase this year, according to the Greenhouse Gas Bulletin of the World Meteorological Organization (WMO), published two weeks before the most important COP since the Paris Agreement, which will be held on 30 November to December 12 in Dubai.
Methane concentrations (CH4) also increased and levels of nitrous oxide (N2O), the third major greenhouse gas, experienced their strongest annual increase ever observed between 2021 and 2022.
“Despite decades of warnings from the scientific community, […] we continue to go in the wrong direction,” commented WMO Secretary-General Petteri Taalas in a statement.
Around 80% of greenhouse gas emissions come from G20 countries, he said at a press conference.
The goal of the 2015 Paris Agreement is to limit global warming to “well below” 2 degrees Celsius since pre-industrial times (1850-1900), and 1.5 degrees if possible.
According to a previous UN report, the average global temperature in 2022 was 1.15°C higher than in pre-industrial times. And 2023 will almost certainly be the hottest year on record, Taalas told reporters.
“The current level of greenhouse gas concentrations is leading us towards an increase in temperatures well above the objectives of the Paris Agreement by the end of the century,” warned Mr. Taalas.
WMO chief paints a grim picture of the future state of the planet: “Weather conditions will become more extreme: intense heat and heavy precipitation, melting ice, rising sea levels and warming and acidification of the oceans ”, and “we will see a surge in socio-economic and environmental costs”.
“No magic wand”
In 2022, the atmospheric concentration of carbon dioxide was 417.9 parts per million (ppm), methane was 1923 parts per billion (ppb), and nitrous oxide was 335.8 ppb. , an increase of 150%, 264% and 124%, respectively, compared to the year 1750.
Carbon dioxide, responsible for around 64% of the climate warming effect, comes mainly from the burning of fossil materials and the production of cement, says the WMO.
As long as emissions continue, CO2 will continue to accumulate in the atmosphere and cause a rise in global temperature. Given the lifespan of CO2the warming already observed will persist for several decades, even if net emissions are quickly reduced to zero.
“There is no magic wand to remove excess carbon dioxide from the atmosphere,” noted Mr. Taalas, who considers it “urgent to reduce the consumption of fossil fuels.”
Methane, contributing some 16% to global warming, is a powerful greenhouse gas that remains in the atmosphere for around ten years.
Its growth rate last year was slightly lower than the record rate observed between 2020 and 2021 while being well above the average annual growth rate of the previous ten years.
“We don’t fully understand why methane concentrations are continuously increasing,” Taalas commented.
As for the rate of increase last year in nitrous oxide, the cause of around 7% of warming, “it has never been so high in modern times”.
The scientific community is well aware of climate change and its implications, but the WMO cites the need for more information in several areas, such as “feedback mechanisms”, such as increased carbon emissions. by soils or the reduction in carbon absorption by the oceans due to climate change.
The WMO also fears that the climate system is near “tipping points”, “situations where a certain degree of change leads to a cascade of self-accelerating and potentially irreversible changes”, such as the dieback of the Amazon rainforest.