The atmospheric level of the potent greenhouse gas (GHG) methane (CH4) is increasing, and is now nearly triple the pre-industrial level. There is a positive feedback loop in the Arctic with increased methane leading to warming and thence to further increase in atmospheric methane. In the warming Arctic methane release is occurring from huge methane-water clathrate deposits, and increasingly from permafrost melting and increased methanogenesis from anaerobic bacteria.
The increase in atmospheric methane (CH4), the increasing contribution from anaerobic bacteria in the warming Arctic , the positive feedback loop involved, and the worsening threat to Humanity and the Biosphere are outlined below.
(1). Increased anaerobic bacterial methanogenesis in the warming Arctic.
Atmospheric methane (CH4) increased from 1.650 ppm (parts per million) in 1985 to 1.775 ppm in 1999, after which it remained constant until 2007, and thence has steadily increased to over 1.9 ppm, 2.7 times the preindustrial level of 0.7 ppm . A possible explanation for this constant level in 1999-2007 is a decreased methane production by anaerobic bacteria in drying swamps. However the increasingly rapid increase in atmospheric CH4 since 2007 is a major concern because CH4 is estimated to have a Global Warming Potential (GWP) of 28–36 over 100 years relative to that of the same mass of carbon dioxide (CO2) , and there is concern over release of CH4 from huge methane-water clathrate stores in the Arctic  as well as from increased anaerobic bacterial methanogenesis in the Arctic due to global warming and tundra permafrost melting [1, 4, 5].
Jeff Tollefson writing in Nature about the “dangerously fast” growth in atmospheric CH4 (2022): “Methane concentrations in the atmosphere raced past 1,900 parts per billion last year, nearly triple preindustrial levels, according to data released in January by the US National Oceanic and Atmospheric Administration (NOAA). Scientists say the grim milestone underscores the importance of a pledge made at last year’s COP26 climate summit to curb emissions of methane, a greenhouse gas at least 28 times as potent as CO2” . A decreasing ratio of the isotope 13C to 14C since 2009 indicates an increasing amount of CH4 from present-day anaerobic microbial action in addition to release of fossil fuel CH4 (fossil fuel CH4 has a higher 13C / 14C ratio because fossil fuel 14C generated by high energy solar irradiation has a half-life of 5,730 years and has had hundreds of millions of year to decay) .
Eric R. Johnston et al. on warming-exacerbated generation of the GHGs CO2 and CH4 from bacterial action in the thawing permafrost (2019): “Ongoing permafrost thaw is expected to stimulate microbial release of greenhouse gases, threatening to further exacerbate climate change (cause positive feedback). In this study, a unique field warming experiment was conducted in Interior Alaska to promote surface permafrost degradation while maintaining uniform hydraulic conditions. After 5 winters of experimental warming by ∼1 °C, microbial community shifts were observed at the receded permafrost/active layer boundary, which reflected more reduced conditions, including increased methanogenesis. In contrast, increased carbohydrate utilization (respiration) was observed at the surface layer. These shifts were relatable to observed increases in CO2 and CH4 release from this study site and the surrounding ecosystem. Collectively, our results demonstrate that microbial responses to warming are rapid and identify potential biomarkers that could be important in modelling” .
Jiajie Feng et al. have also commented on global warming increasing methanogenesis by anaerobic bacteria (2020): “Our findings support the hypothesis that bacterial communities continue to evolve and diverge into new states (sensitivity) after long-term warming. Consequently, the higher functional capacity of microbial decomposition of soil C under warming contributes to higher soil respiration and CH4 flux, which in turn accelerates tundra C loss.… [our] results could be crucial in assessing C dynamics in permafrost regions since the warming-induced thaw of permafrost regions exposes previously protected C stock to microbial activity. These findings also provide a mechanistic explanation for the recent observation that warming at our study site increased the annual cellulose decomposition rate at a soil depth of 0–10 cm by a factor of two… an increased soil nutrient availability associated with warming may further amplify C loss and consequently impose positive feedback to climate warming. Collectively, our results show that 5-year warming significantly altered the bacterial composition and functional structure of microbial communities in permafrost regions, revealing an evolving sensitivity to warming. Soil thaw depth was the strongest factor shaping bacterial taxonomic composition, C decomposition potential, and network topological properties, demonstrating that warming-induced thaw of permafrost regions fundamentally restructures the associated bacterial communities. Therefore, we project that microbial responses to long-term warming will lead to positive feedback enhancing C decomposition in tundra regions” .
Methane-release from the thawing Arctic involves a dangerous positive feedback loop: elevated atmospheric greenhouse gases (CO2, CH4 and N2O-> increase warming -> increased atmospheric CH4 and CO2 -> further increased warming . Presently atmospheric levels of the greenhouse gases (GHGs) CO2, CH4 and N2O (nitrous oxide) are increasing at an increasing rate [1, 2. 6, 7]. The CO2 comes from fossil fuel burning, carbon fuel burning in general, forest fires, and Biosphere respiration. The CH4 comes from the release of CH4 from huge CH4-H2O clathrate stores in the Arctic, methanogenesis by anaerobic bacteria (in swamps, rice fields, urban waste dumps, and the warming Arctic), and as fugitive emissions from fossil fuel extraction and exploitation. The N2O derives from oxidation of nitrogen fertilizers applied in agriculture [8, 9].
(2). Methane threat and dangerous atmospheric GHG level of about 600 ppm CO2-equivalent by 2050 in the absence of climate action.
Over a 100 year time frame the Global Warming Potential (GWP) relative to that for the same mass of CO2 (1.0) is 28-36 (CH4)  and 298 (N2O) [8, 9, 10]. On a 20 year time frame the GWP is 1.0 (CO2), 105 (CH4, with aerosol impacts included) , and 289 (N2O) [8, 9]. The atmospheric GHG level is the sum of all GHG effects and is expressed as CO2-equivalent.
Thus back in 2010 Dr Andrew Glikson (a paleoclimatologist and earth scientist) estimated that the atmospheric GHG level was 460 ppm CO2-equivalent with dire implications for the planet: “Recent paleoclimate studies, using multiple proxies (soil carbonate d13C, alkenones, boron/calcium, stomata leaf pores), indicate that the current CO2 level of 388 ppm and CO2-equivalent level of 460 ppm (which includes the methane factor), commit warming above pre-industrial levels to 3 to 4 degrees C in the tropics and 10 degrees C in polar regions, tracking toward an ice-free Earth… At 4 degrees Celsius advanced to total melting of the Greenland and Antarctic ice sheets leads to sea levels tens of meters higher than at present. Further rise of CO2-e above 500 ppm and mean global temperatures above 4 degrees C can only lead toward greenhouse Earth conditions such as existed during the Cretaceous and early Cainozoic” .
A decade later in 2020 Dr Andrew Glikson commented on the “myth” of “zero net emissions by 2050” and estimated that the Earth is tracking to a disastrous 600 ppm CO2-equivalent in 2050:“Yet another cruel hoax perpetrated in the wake of more than 50 years of obfuscation and denial of environment and climate science. This is because: A) The proposed zero-emission by 2050 overlooks the long term nature of ongoing investments, mining and drilling… B) The proposed reductions in emissions are to be mainly confined to domestic emissions, neglecting carbon exports… C) The proposed reductions take no account of the accelerated rise of temperatures due to the radiative effects of the rising greenhouse gas concentration in the atmosphere, which by 2050 will be tracking toward 600 parts per million CO2-equivalent of combined carbon and nitrous oxide gases. These are already generating amplifying feedbacks from land and ocean which drive temperatures higher, rendering reductions of emissions ineffective. At that stage, the large ice sheets would experience irreversible melting. For this reason, the essential reductions in emission must be accompanied by sequestration of atmospheric greenhouse gases by at least the amount of annual emissions” .
It is useful to crudely examine this circa “600 ppm CO2-equivalent by 2050” estimate:
(A). In 2022 the atmospheric CO2 is 418.0 ppm as compared to 406.2 ppm in 2017  i.e. it has increased by 11.8 ppm over 5 years. Assuming this rate of increase remains the same (oil and gas use are still increasing but coal use has possibly peaked) ), we can estimate an increase over the next 28 years of 11.8 ppm CO2 x 28 years/5 years = 66 ppm CO2, and an atmospheric CO2 in 2050 of 418 + 66 = 484 ppm CO2.
(B). Atmospheric CH4 was 1,825 ppb (parts per billion) in 2015 and increased to 1,870 ppb by 2020, an increase of 45 ppb over 5 years or 9 ppb per year. Assuming the same rate of increase over the next 30 years, the atmospheric CH4 increase will be 9 ppb per year x 30 years = 270 ppb CH4. Accordingly the atmospheric CH4 will be 1,870 + 270 = 2,140 ppb CH4 in 2050. According to the US EPA: “Methane (CH4) is estimated to have a GWP of 28–36 over 100 years” . Assuming a GWP of 36 for CH4, the atmospheric CH4 in 2050 will be 2.140 ppm CH4 x 36 ppm CO2-e/ppm CH4 = 77 ppm CO2-e.
(C). Accordingly, based on these assumptions and ignoring the N2O contribution, one can crudely estimate that in the absence of radical global action atmospheric GHG in 2050 on present trends will be 484 + 77 = 561 ppm CO2-e. A similar calculation that ignores the N2O contribution estimates an atmospheric GHG level of 485 ppm CO2-e or about 500 ppm CO2-e in 2020.
Final comments and conclusions.
The atmospheric CH4 level is steadily increasing, noting that CH4 has a Global Warning Potential (GWP) 105 times greater than that of the same mass of CO2 on a 20 year time frame basis and including aerosol impacts . CH4 is presently being released from the warming Arctic tundra and the Arctic Ocean sea bed. It has been estimated that 50 Gt of CH4 will be released in the Arctic in coming decades . This corresponds to 50 Gt CH4 / (1 t CH4 per 105 t CO2-equivalent ) = 5,250 Gt CO2-equivalent or 5.8 times greater than the IPCC-estimated Carbon Budget of 900 Gt CO2 for an 83% probability of avoiding a catastrophic +2C temperature rise (Table 2 ).
According to the IPCC (2021), compared to 1850–1900, global surface temperature averaged over 2081–2100 is very likely to be higher by 1.0°C to 1.8°C under the very low GHG emissions scenario considered (SSP1-1.9), by 2.1°C to 3.5°C in the intermediate scenario (SSP2-4.5) and by 3.3°C to 5.7°C under the very high GHG emissions scenario (SSP5-8.5). The last time global surface temperature was sustained at or above 2.5°C higher than 1850–1900 was over 3 million years ago (Section B1.1 [15, 16]). The Summary for Policymakers for the IPCC Fifth Assessment Report (AR5) (2014) stated “About 450 ppm CO2-eq, likely to limit warming to 2°C above pre-industrial levels” , but 478 ppm CO2-eq was already attained by 2013 [18, 19]. The atmospheric CO2-equivalent was about 460 ppm in 2010 , 478 ppm in 2013 [18, 19], is presently about 500 ppm, and is heading towards about 600 ppm by 2050 .
Further, but for the cooling effect of atmospheric sulphate aerosols we would presently have a catastrophic circa +2C of warming. The present global warming of about +1.1C is largely due to the burning of carbon fuels . However a consequence of burning fossil fuels is also generation of sulphur dioxide (SO2) that in turn generates global dimming sulphate aerosols in the upper atmosphere that restrict global warming to +1.1C from the circa +2C that it would be otherwise [15, 16, 20, 21]. The IPCC estimates that the global temperature rise will reach +1.5C in the coming decade [15, 16] but the Emissions Gap Report from the UN Environment Programme has estimated that the national commitments at the 2015 Paris Climate Conference mean a temperature rise of +3.2C . Dr Andrew Glikson estimates that “mean temperature could reach 2°C by 2030, 3°C by the 2050s and 4°C by 2100, inducing heat waves and major fires” .
We have effectively run out of time to avoid a catastrophic plus 2C temperature rise. However decent people are obliged to do everything they can to make the future “less bad” for future generations . Decent people must (a) inform everyone they can (the mendacious Mainstream journalist, editor, proprietor, politician, academic and commentariat presstitutes certainly won’t), and (b) urge and apply Boycotts, Divestment and Sanctions (BDS) against people, politicians, parties, companies, corporations, and countries disproportionately involved in Humanity- and Biosphere-threatening climate criminality. There is no Planet B.
. Jeff Tollefson, “Scientists raise alarm over “dangerously fast” growth in methane”, Nature, 8 February 2022: https://www.nature.com/articles/d41586-022-00312-2?utm_source=Nature+Briefing&utm_campaign=d6c58c6a9d-briefing-dy-20220208&utm_medium=email&utm_term=0_c9dfd39373-d6c58c6a9d-44714333 .
. National Oceanic and Atmospheric Administration (NOAA), “Trends in atmospheric methane”: http://www.esrl.noaa.gov/gmd/ccgg/trends_ch4/index.html .
. “Methane bomb threat”: https://sites.google.com/site/methanebombthreat/ .
. Eric R. Johnston et al., “Responses of tundra soil microbial communities to half a decade of experimental warming at two critical depths”, PNAS, 116 (30) 15096-15105, 23 July, 2019: https://www.pnas.org/content/116/30/15096 .
. Jiajie Feng et al., “Warming-induced permafrost thaw exacerbates tundra soil carbon decomposition mediated by microbial community”, Microbiome volume 8, Article number 3, 2020: https://microbiomejournal.biomedcentral.com/articles/10.1186/s40168-019-0778-3 .
. US NOAA, “Trends in atmospheric carbon dioxide”: https://gml.noaa.gov/ccgg/trends/mlo.html .
. US NOAA, “Trends in atmospheric nitrous oxide”: https://gml.noaa.gov/ccgg/trends_n2o/ .
. “2011 climate change course”: https://sites.google.com/site/yarravalleyclimateactiongroup/2011-climate-change-course .
. Gideon Polya, “Climate Crisis, Climate Genocide & Solutions”, Korsgaard Publishing, Germany, 2021.
. US EPA, “Understanding global warming potentials”: https://www.epa.gov/ghgemissions/understanding-global-warming-potentials .
. D.T. Shindell, G. Faluvegi, D.M. Koch, G.A. Schmidt, N. Unger, and S.E. Bauer, 2009: Improved attribution of climate forcing to emissions. Science, 326, 716-718, doi:10.1126/science.1174760: https://pubs.giss.nasa.gov/abs/sh05500b.html .
. Andrew Glikson, “CO2 Mass Extinction Of Species And Climate Change”, Countercurrents, 22 February 2010: https://countercurrents.org/glikson220210.htm .
. Andrew Glikson, “The myth of “zero net emissions by 2050”, Pearls & Irritations, 14 December 2020: https://johnmenadue.com/the-myth-of-zero-net-emissions-by-2050/ .
. Gideon Polya, “Wrong way go back – global sectoral greenhouse gas emissions are all in the wrong direction”, Countercurrents, 20 March 2020: https://countercurrents.org/2020/03/wrong-way-go-back-global-sectoral-greenhouse-gas-emissions-are-all-in-the-wrong-direction/ .
. Intergovernmental Panel on Climate Change (IPCC), “Climate Change 2021. The physical science basis. Summary for Policymakers”, 7 August 2021: https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_SPM.pdf .
. Gideon Polya, “Summary of the Summary for Policymakers of the IPCC’s “Climate Change 2021”, Countercurrents, 12 August 2021: https://countercurrents.org/2021/08/summary-of-the-summary-for-policymakers-of-the-ipccs-climate-change-2021/ .
. The IPCC, “Climate Change 2014 Synthesis Report, Approved Summary for Policy Makers”, 1 November 2014: http://www.ipcc.ch/pdf/assessment-report/ar5/syr/SYR_AR5_SPM.pdf .
. Gideon Polya , “International Consensus-Based IPCC Summary For Policymakers (2014) Downplays Acute Seriousness Of Climate Crisis”, Countercurrents, 12 November, 2014: https://www.countercurrents.org/polya121114.htm .
. Ron Prinn, “400 ppm CO2? Add other GHGs and its equivalent to 478 ppm”, Oceans at MIT, 6 June 2013: http://oceans.mit.edu/featured-stories/5-questions-mits-ron-prinn-400-ppm-threshold .
. Andrew Glikson, “Planetary Ecocide — The Crime Against Life on Earth”, Countercurrents, 11 December 2021: https://countercurrents.org/2021/12/planetary-ecocide-the-crime-against-life-on-earth/
. Andrew Glikson, “Inferno: from climate denial to planetary arson”, Countercurrents, 8 September 2019: https://countercurrents.org/2019/09/inferno-from-climate-denial-to-planetary-arson .
. “UN emissions report: World on course for more than 3 degree spike, even if climate commitments are met”, UN News, 26 November 2019: https://news.un.org/en/story/2019/11/1052171 .
Dr Gideon Polya taught science students at La Trobe University, Melbourne, Australia over 4 decades. He published some 130 works in a 5 decade scientific career, notably a huge pharmacological reference text “Biochemical Targets of Plant Bioactive Compounds”. He has also published “Body Count. Global avoidable mortality since 1950” (2007, 2022) and “Jane Austen and the Black Hole of British History” (1998, 2008). He has recently published “US-imposed Post-9-11 Muslim Holocaust & Muslim Genocide” (2020), and “Climate Crisis, Climate Genocide & Solutions” (2021). For images of Gideon Polya’s huge paintings for the Planet, Peace, Mother and Child see: http://sites.google.com/site/artforpeaceplanetmotherchild/ .