Heat-Trapping Gases In The Atmosphere Reached Historic Highs In 2023, NOAA Says

(Photo : Getty Images/Philippe LOPEZ)

Levels of the three most important human-caused greenhouse gases, carbon dioxide (CO2), methane, and nitrous oxide, reached historic highs last year, according to US scientists.

Heat-Trapping Gases

Carbon dioxide, the most important and abundant greenhouse gas produced by humans, increased by the third highest in 65 years of record-keeping in 2023, according to the National Oceanic and Atmospheric Administration (NOAA).

Scientists are especially concerned about the rapid increase in atmospheric quantities of methane, a shorter-lived but more potent heat-trapping gas. Both increased by 5.5% during the last decade.

The 2.8 parts per million increase in carbon dioxide airborne levels from January 2023 to December was not as substantial as the spikes in 2014 and 2015, but it was greater than any other year since 1959, when precise data began.

Carbon dioxide levels in 2023 averaged 419.3 parts per million, a 50% increase over pre-industrial times.

Last year's methane increase of 11.1 parts per billion was less than the record annual climb from 2020 to 2022. The average was 1922.6 parts per billion last year. It has climbed 3% within the last five years and jumped 160% from pre-industrial levels, exhibiting higher rates of increase than carbon dioxide.

Methane emissions into the atmosphere are caused by natural wetlands, agriculture, animals, landfills, leaks, and the purposeful flaring of natural gas in the oil and gas sector.

Methane's decadal surge should frighten us, said Stanford University climate scientist Rob Jackson, who oversees the Global Carbon Project, which measures global emissions of carbon dioxide.

"Fossil fuel pollution is warming natural systems like wetlands and permafrost. Those ecosystems are releasing even more greenhouse gases as they heat up. We're caught between a rock and a charred place," he added.

Nitrous oxide, the third most significant human-caused greenhouse gas, increased by 1 part per billion last year to new highs, but not as dramatically as in 2020 and 2021. According to the EPA, agriculture, fuel combustion, manure, and industrial operations all contribute to nitrous oxide, which can stay in the atmosphere for up to 100 years.

Abundance Presence Of Gases

The increasing abundance of greenhouse gases is stimulating a rise in global temperature-last year was the warmest ever measured worldwide-as well as accompanying consequences such as floods, droughts, heatwaves, and wildfires.

It is also pushing the world into a state not seen since prior to human civilization. Carbon dioxide levels today are comparable to what they were roughly 4 million years ago, in an era when sea levels were around 75 feet higher than they are now. The average temperature was significantly hotter, and huge forests occupied portions of the now-frozen Arctic.

The climate issue has a long duration due to the lag between CO2 levels and their impact, as well as the hundreds of years that emissions remain in the atmosphere.

Scientists have cautioned that countries must quickly reduce emissions to net zero and then begin removing carbon from the atmosphere to limit future temperature increases.