Greenhouse Gas Concentrations Reach Record Levels as Scientists Raise Concerns
In 2023, greenhouse gas concentrations in the atmosphere hit new record highs, ensuring future temperature rises for years ahead, the United Nations cautioned on Monday.
The levels of the three primary greenhouse gases—carbon dioxide, methane, and nitrous oxide, which contribute to climate warming—have all risen once more over the past year, according to the UN’s weather and climate agency.
The World Meteorological Organization reported that carbon dioxide is accumulating in the atmosphere at an unprecedented rate, increasing by more than 10 percent over the past two decades.
The WMO’s annual Greenhouse Gas Bulletin was released in advance of the COP29 UN climate summit scheduled for November 11-22 in Baku.
“Another year. Another record. This should raise alarm bells for decision-makers,” said WMO chief Celeste Saulo in a statement.
“We are clearly straying from the goals set by the Paris Agreement.”
Commitments of the 2015 Paris Agreement
Under the 2015 Paris Agreement, nations committed to limiting global warming to “well below” two degrees Celsius above the average levels recorded between 1850 and 1900, and to strive for a limit of 1.5 degrees Celsius if feasible.
As long as emissions persist, greenhouse gases will continue to build up in the atmosphere, resulting in higher global temperatures, according to the WMO.
Last year, global temperatures on land and sea reached “the highest levels recorded since 1850,” the organization stated.
Given the long lifespan of CO2 in the atmosphere, current temperature levels are expected to persist for decades, even if emissions rapidly decrease to net zero.
In 2023, CO2 concentrations reached 420 parts per million (ppm), while methane levels stood at 1,934 parts per billion and nitrous oxide at 336 parts per billion.
These figures represent increases of 151 percent, 265 percent, and 125 percent compared to pre-industrial levels from before 1750.
“These numbers are more than mere statistics. Every part per million and every fraction of a degree rise in temperature has a tangible effect on our lives and our planet,” Saulo stated.
CO2 contributes approximately 64 percent of the warming effect on the climate.
Rising CO2 Levels and Their Implications
The annual increase of 2.3 ppm marks the 12th consecutive year with a rise exceeding two ppm, a trend attributed to “historically high fossil fuel CO2 emissions in the 2010s and 2020s,” according to the report.
Last year’s level is 11.4 percent higher than the 337.1 ppm recorded in 2004.
“CO2 is accumulating in the atmosphere at a rate not seen at any time in human history,” the report stated, noting that the current atmospheric CO2 concentration is 51 percent above pre-industrial levels.
The last time Earth had a similar concentration of CO2 was three to five million years ago, a period when temperatures were 2-3 degrees Celsius warmer, and sea levels were 10-20 meters higher than today.
Nearly half of CO2 emissions remain in the atmosphere, while the remainder is absorbed by oceans and land ecosystems.
However, WMO deputy chief Ko Barrett cautioned that we are now “facing a potential vicious cycle.”
Climate change could soon lead ecosystems to become significant sources of greenhouse gases, she explained.
“Wildfires could emit more carbon into the atmosphere, while warmer oceans might absorb less CO2. As a result, more CO2 could remain in the atmosphere, exacerbating global warming.”
Read the original article on: Science Alert
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