Greenhouse Gases Reached Record High in 2021 as Methane Logged Largest Jump Ever

ON 11/05/2022 AT 01:07 AM

A new report just released by the World Meteorological Organization said atmospheric concentrations of carbon dioxide, methane, and nitrous oxide in 2021 climbed to their highest levels yet. The worst news was that methane concentrations rose by the single largest increase since records were recorded.

Greenhouse gas emissions

The Greenhouse Gas Effect causes more solar radiation to be trapped by the atmosphere as the concentration of gases such as carbon dioxide, methane (CH4), and nitrous oxide increase. Photo: A Loose Necktie, CC

The October 26, 2022, issue of the WMO Greenhouse Gas Bulletin just revealed some very bad news for the planet.

Using data provided by 55 members of the World Meteorological Organization, the agency reported that in 2021 all three of the primary greenhouse gases (GHG) responsible for global heating had risen to new highs.

On top of that already difficult news, carbon dioxide (CO2) levels increased by a rate faster than the average annual growth rate over the last ten years, closing at 415.7 parts per million (ppm) and a concentration 149% of pre-industrial levels.

Carbon Dioxide concentrations

Carbon dioxide concentrations through 2021. Photo: World Meteorological Organization

The increase in carbon dioxide concentrations, mostly tied to burning of fossil fuels and roughly 8% from production and use of cement, are up significantly since the year of pandemic lock downs in 2020.

The WMO report also flagged concerns that as carbon dioxide levels rise, signs are already pointing to downward shifts in the amount of atmospheric carbon dioxide which is reabsorbed by the planet. According to their studies, of the carbon dioxide which anthropogenic (human-caused) activities have pushed up into the atmosphere from 2011 through 2019, 29% was absorbed by land masses principally in forests and other plants, 26% was taken up by the ocean, resulting in acidification and changes in marine ecosystems close to the surface, and just under 48% remained in the atmosphere. Those ratios are now shifting, the WMO said, particularly within land masses which in many areas of the world may have reached limits as to how much they can contain.

Methane (CH4), with the most severe impacts by volume on radiative forcing — the ability of the gas to trap solar energy in the atmosphere and warm the planet — at an average of 28 to 36 times the Global Warming Potential (GWP) of carbon dioxide over a period of 100 years, showed concentrations in 2021 rose to 1908 ppb, a level equivalent to 262% of pre-industrial levels.

Methane atmospheric concentrations through 2021.

Methane concentrations in the atmosphere through 2021. Photo: World Meteorological Organization

The increase in methane concentrations from 2020 was 18 ppb, the biggest year-on-year increase since systematic record-taking of methane amounts began in 1983. That rapid climb, shown clearly in an even more disturbing graph below, comes after a previous record climb in concentrations of 15 ppb from 2019 to 2020

Methane atmospheric concentration increases in the atmosphere

Annual increases in methane concentrations in the atmosphere thorough 2021. Photo: World Meteorological Organization

Although the researchers are still attempting to understand why methane rates have increased so fast, data already has demonstrated that the largest contributor to methane release increases since 2007 comes not from the production of fossil fuels and the meat industry but perhaps instead from biogenic sources, such as decomposition in rice paddies and wetlands and the release of Arctic methane. The scientists are also looking at the increasing impact of feedback loop effects such as the more rapid emissions releases in those sources as temperatures rise.

Another issue which the WMO says may be behind the short-term methane increases are widespread La Niña events which were more severe than normal in the last two years. Such weather patterns produce high levels of tropical rainfall, which help release additional trapped methane sources in organic groundcover.

Not cited in the report but also believed to be a major source of the methane increase is the increasing rate of permafrost melting in the Arctic and near sub-Arctic. A detailed analysis of what is happening there suggested that, with the Arctic warming at rates up to 4 times the rest of the world, the Arctic may by mid to late century be emitting more total emissions now as some of the biggest industrialized nations have in the entire history of their entire atmospheric GHG contributions. Methane previously trapped in frozen form and as released from the permafrost will make up a substantial portion of those contributions.

The third most damaging gas in terms of overall radiative forcing, nitrous oxide (N2O), with 265-298 times the GWP of carbon dioxide, climbed last year to its own new high. The 2021 concentration of these gases reached a level of 334.5 ppb, a level amounting to 124% of pre-industrial levels.

N2O concentrations

Nitrous oxide concentrations in the atmosphere through 2021. Photo: World Meteorological Organization

The WMO data shows that 57% of nitrous oxide comes from natural sources and 43% from anthropogenic sources such as burning of biomasses and fertilizer use.

As others have noted, the solution to slowing the relentless growth of emissions for all three of these greenhouse gases is about far more than throttling back on emissions from industrial and agricultural sources, according to WMO Secretary-General Prof. Petteri Taalas.

“We need to transform our industrial, energy and transport systems and whole way of life,” he said in a statement released with the new report.

Even with those changes, which will of necessity be extensive, the trajectory for global heating going forward has already been set by our past actions, for the most part. A second part of the equation for survival — and something which needs far more public discussion — involves what we as a species must do to adapt to the increasingly inhospitable planet we will be stuck with as the 21st century rolls on.