Earth:Arctic methane emissions

From HandWiki
Short description: Release of methane in the Arctic
Main sources of global methane emissions (2008-2017):[1] Contributions from the Arctic are part of the fifth column called other natural emissions.

Arctic methane emissions contribute to a rise in methane concentrations in the atmosphere. Whilst the Arctic region is one of many natural sources of the greenhouse gas methane, there is nowadays also a human component to this due to the effects of climate change.[2] In the Arctic, the main human-influenced sources of methane are thawing permafrost, Arctic sea ice melting, clathrate breakdown and Greenland ice sheet melting. This methane release results in a positive climate change feedback (meaning one that amplifies warming), as methane is a powerful greenhouse gas.[3] When permafrost thaws due to global warming, large amounts of organic material can become available for methanogenesis and may therefore be released as methane.[4]

Since around 2018, there has been consistent increases in global levels of methane in the atmosphere, with the 2020 increase of 15.06 parts per billion breaking the previous record increase of 14.05 ppb set in 1991, and 2021 setting an even larger increase of 18.34 ppb.[5] However, there is currently no evidence connecting the Arctic to this recent acceleration.[6] In fact, a 2021 study indicated that the methane contributions from the Arctic were generally overestimated, while the contributions of tropical regions were underestimated.[7]

Nevertheless, the Arctic's role in global methane trends is considered very likely to increase in the future. There is evidence for increasing methane emissions since 2004 from a Siberian permafrost site into the atmosphere linked to warming.[8]

Mitigation of CO2 emissions by 2050 (i.e. reaching net zero emissions) is probably not enough to stop the future disappearance of summer Arctic Ocean ice cover. Mitigation of methane emissions is also necessary and this has to be carried out over an even shorter period of time.[9] Such mitigation activities need to be carried out in three main sectors: oil and gas, waste and agriculture. Using available measures this could amount to global reductions of ca.180 Mt/yr or about 45% of the current (2021) emissions by 2030.[10]

Observed values and processes

See also: Earth:Atmospheric methane and Greenhouse gas emissions
Methane concentrations in Utqiaġvik, Alaska (formerly known as Barrow). A peak methane concentration of 1988 parts per billion was reached in October 2019.[11]
Image showing thawed permafrost resulting in thermokarst, a source of methane released from permafrost.

NOAA annual records for methane concentrations in the atmosphere have been updated since 1984. They show substantial growth during the 1980s, a slowdown in annual growth during the 1990s, a plateau (including some years of declining atmospheric concentrations) in the early 2000s and another consistent increase beginning in 2007. Since around 2018, there has been consistent annual increases in global levels of methane, with the 2020 increase of 15.06 parts per billion breaking the previous record increase of 14.05 ppb set in 1991, and 2021 setting an even larger increase of 18.34 ppb.[5]

Due to the relatively short lifetime of atmospheric methane (7–12 years compared to 100s of years for CO2[12]) its global trends are more complex than those of carbon dioxide.

These trends alarm climate scientists, with some suggesting that they represent a climate change feedback increasing natural methane emissions well beyond their preindustrial levels.[13] However, there is currently no evidence connecting the Arctic to this recent acceleration.[6] In fact, a 2021 study indicated that the role of the Arctic was typically overestimated in global methane accounting, while the role of tropical regions was consistently underestimated.[7] The study suggested that tropical wetland methane emissions were the culprit behind the recent growth trend, and this hypothesis was reinforced by a 2022 paper connecting tropical terrestrial emissions to 80% of the global atmospheric methane trends between 2010 and 2019.[14]

Nevertheless, the Arctic's role in global methane trends is considered very likely to increase in the future. There is evidence for increasing methane emissions since 2004 from a Siberian permafrost site into the atmosphere linked to warming.[8]

Radiocarbon dating of trace methane in lake bubbles and soil organic carbon concluded that 0.2 to 2.5 Pg of permafrost carbon has been released as methane and carbon dioxide over the last 60 years.[15] The 2020 heat wave may have released significant methane from carbonate deposits in Siberian permafrost.[16]

Methane emissions by the permafrost carbon feedback—amplification of surface warming due to enhanced radiative forcing by carbon release from permafrost—could contribute an estimated 205 Gt of carbon emissions, leading up to 0.5 °C (0.9 °F) of additional warming by the end of the 21st century.[17] However, recent research based on the carbon isotopic composition of atmospheric methane trapped in bubbles in Antarctic ice suggests that methane emissions from permafrost and methane hydrates were minor during the last deglaciation, suggesting that future permafrost methane emissions may be lower than previously estimated.[18]

Comparison of Arctic and Antarctic atmosphere measurements

Atmospheric methane concentrations are 8–10% higher in the Arctic than in the Antarctic atmosphere. During cold glacier epochs, this gradient decreases to insignificant levels.[19] Land ecosystems are thought to be the main sources of this asymmetry, although it has been suggested in 2007 that "the role of the Arctic Ocean is significantly underestimated."[20] Soil temperature and moisture levels are important variables in soil methane fluxes in tundra environments.[21][22]

Sources of methane in the Arctic

See also: Methane emissions

Large quantities of methane are stored in the Arctic in natural gas deposits, permafrost, and as undersea clathrates. Permafrost and clathrates degrade on warming,[23] thus large releases of methane from these sources may arise as a result of global warming.[24][25][26] Other sources of methane include submarine taliks, river transport, ice complex retreat, submarine permafrost and decaying gas hydrate deposits.[27]A 2024 assessment estimated the total methane emissions from Arctic–Boreal landforms to be approximately 48.7 (13.3–86.9) Tg CH₄ yr⁻¹, with marine sources contributing around 4.9 (0.4–19.4) Tg CH₄ yr⁻¹.[28]Permafrost contains almost twice as much carbon as the atmosphere,[29] with ~20 Gt of permafrost-associated methane trapped in methane clathrates.[30] Permafrost thaw results in the formation of thermokarst lakes in ice-rich yedoma deposits.[31]Methane frozen in permafrost is slowly released as permafrost thaws.[32]

Thawing permafrost

PMMA chambers used to measure methane and CO2 emissions in Storflaket peat bog near Abisko, northern Sweden.
This section is an excerpt from Permafrost carbon cycle#Methane emissions[ edit ]

Arctic sea ice melting

This section is an excerpt from Arctic sea ice decline#Atmospheric chemistry[ edit ]

Clathrate breakdown

This section is an excerpt from Clathrate gun hypothesis[ edit ]
This section is an excerpt from Clathrate gun hypothesis#Current outlook[ edit ]

Greenland ice sheet melting

A 2014 study found evidence for methane cycling below the ice sheet of the Russell Glacier, based on subglacial drainage samples which were dominated by Pseudomonadota bacteria. During the study, the most widespread surface melt on record for the past 120 years was observed in Greenland; on 12 July 2012, unfrozen water was present on almost the entire ice sheet surface (98.6%). The findings indicate that methanotrophs could serve as a biological methane sink in the subglacial ecosystem, and the region was, at least during the sample time, a source of atmospheric methane. Scaled dissolved methane flux during the four months of the summer melt season for the Russell Glacier catchment area (1200 km2) was estimated at 990 tonnes CH4. Because this catchment area is representative of similar Greenland outlet glaciers, the researchers concluded that the Greenland Ice Sheet may represent a significant global methane source.[33]

A study in 2016 concluded that methane clathrates may exist below Greenland's and Antarctica's ice sheets, based on past evidence.[34]

Reducing methane emissions

See also: Earth:Climate change mitigation

More than half of global methane emissions originate from human activities across three main sectors: fossil fuels (35% of human-caused emissions), waste (20%), and agriculture (40%).[10] Within the fossil fuel sector, oil and gas extraction, processing, and distribution contribute 23%, while coal mining accounts for 12% of these emissions. In the waste sector, landfills and wastewater comprise about 20% of global anthropogenic emissions. In agriculture, livestock emissions from manure and enteric fermentation make up roughly 32%, and rice cultivation contributes 8% of global anthropogenic emissions. Mitigation using available measures could reduce these methane emissions by about 180 Mt/yr or about 45% by 2030.[10]

Mitigation of CO2 emissions by 2050 (i.e. reaching net zero emissions) is probably not enough to stop the future disappearance of summer Arctic Ocean ice cover. Mitigation of methane emissions is also necessary and this has to be carried out over an even shorter period of time.[9]

Flaring methane from oil and gas operations

ARPA-E has funded a research project from 2021-2023 to develop a "smart micro-flare fleet" to burn off methane emissions at remote locations.[35][36][37]

A 2012 review article stated that most existing technologies "operate on confined gas streams of 0.1% methane", and were most suitable for areas where methane is emitted in pockets.[38]

If Arctic oil and gas operations use Best Available Technology (BAT) and Best Environmental Practices (BEP) in petroleum gas flaring, this can result in significant methane emissions reductions, according to the Arctic Council.[39]

See also

References

  1. ↑ Saunois, M. et al. (July 15, 2020). "The Global Methane Budget 2000–2017" (in en). Earth System Science Data 12 (3): 1561–1623. doi:10.5194/essd-12-1561-2020. ISSN 1866-3508. Bibcode: 2020ESSD...12.1561S. https://essd.copernicus.org/articles/12/1561/2020/. Retrieved 28 August 2020. 
  2. ↑ Bloom, A. A.; Palmer, P. I.; Fraser, A.; Reay, D. S.; Frankenberg, C. (2010). "Large-Scale Controls of Methanogenesis Inferred from Methane and Gravity Spaceborne Data". Science 327 (5963): 322–325. doi:10.1126/science.1175176. PMID 20075250. Bibcode: 2010Sci...327..322B. https://authors.library.caltech.edu/57435/2/Bloom.SOM.pdf. 
  3. ↑ Cheng, Chin-Hsien; Redfern, Simon A. T. (23 June 2022). "Impact of interannual and multidecadal trends on methane-climate feedbacks and sensitivity". Nature Communications 13 (1): 3592. doi:10.1038/s41467-022-31345-w. PMID 35739128. Bibcode: 2022NatCo..13.3592C. 
  4. ↑ Zimov, Sa; Schuur, Ea; Chapin, Fs 3Rd (Jun 2006). "Climate change. Permafrost and the global carbon budget". Science 312 (5780): 1612–3. doi:10.1126/science.1128908. ISSN 0036-8075. PMID 16778046. https://www.science.org/doi/10.1126/science.1128908. 
  5. ↑ 5.0 5.1 "Trends in Atmospheric Methane". https://gml.noaa.gov/ccgg/trends_ch4/. 
  6. ↑ 6.0 6.1 "Increasing anthropogenic methane emissions arise equally from agricultural and fossil fuel sources". Environmental Research Letters 15 (7): 071002. 15 July 2020. doi:10.1088/1748-9326/ab9ed2. Bibcode: 2020ERL....15g1002J. 
  7. ↑ 7.0 7.1 "Improved Constraints on Global Methane Emissions and Sinks Using δ13C-CH4". Global Biogeochemical Cycles 35 (6). 8 May 2021. doi:10.1029/2021GB007000. PMID 34219915. Bibcode: 2021GBioC..3507000L. 
  8. ↑ 8.0 8.1 Rößger, Norman; Sachs, Torsten; Wille, Christian; Boike, Julia; Kutzbach, Lars (27 October 2022). "Seasonal increase of methane emissions linked to warming in Siberian tundra". Nature Climate Change 12 (11): 1031–1036. doi:10.1038/s41558-022-01512-4. Bibcode: 2022NatCC..12.1031R. https://www.researchgate.net/publication/364812576. Retrieved 21 January 2023. 
  9. ↑ 9.0 9.1 Sun, Tianyi; Ocko, Ilissa B; Hamburg, Steven P (2022-03-15). "The value of early methane mitigation in preserving Arctic summer sea ice" (in en). Environmental Research Letters 17 (4): 044001. doi:10.1088/1748-9326/ac4f10. ISSN 1748-9326. Bibcode: 2022ERL....17d4001S. 
  10. ↑ 10.0 10.1 10.2 United Nations Environment Programme and Climate and Clean Air Coalition (2021). Global Methane Assessment: Benefits and Costs of Mitigating Methane Emissions.. Nairobi: Nairobi: United Nations Environment Programme.. ISBN 9789280738544. 
  11. ↑ US Department of Commerce, NOAA. "Global Monitoring Laboratory - Data Visualization" (in EN-US). https://gml.noaa.gov/dv/iadv/graph.php?code=BRW&program=ccgg&type=ts(. 
  12. ↑ "Methane | Vital Signs" (in en). 16 June 2023. https://climate.nasa.gov/vital-signs/methane?intent=121. 
  13. ↑ "Scientists raise alarm over 'dangerously fast' growth in atmospheric methane". Nature. 8 February 2022. https://www.nature.com/articles/d41586-022-00312-2. Retrieved 14 October 2022. 
  14. ↑ Feng, Liang; Palmer, Paul I.; Zhu, Sihong; Parker, Robert J.; Liu, Yi (16 March 2022). "Tropical methane emissions explain large fraction of recent changes in global atmospheric methane growth rate" (in en). Nature Communications 13 (1): 1378. doi:10.1038/s41467-022-28989-z. PMID 35297408. Bibcode: 2022NatCo..13.1378F. 
  15. ↑ Walter Anthony, Katey; Daanen, Ronald; Anthony, Peter; Schneider von Deimling, Thomas; Ping, Chien-Lu; Chanton, Jeffrey P.; Grosse, Guido (2016). "Methane emissions proportional to permafrost carbon thawed in Arctic lakes since the 1950s" (in en). Nature Geoscience 9 (9): 679–682. doi:10.1038/ngeo2795. ISSN 1752-0908. Bibcode: 2016NatGe...9..679W. https://www.nature.com/articles/ngeo2795. 
  16. ↑ Froitzheim, Nikolaus; Majka, Jaroslaw; Zastrozhnov, Dmitry (2021). "Methane release from carbonate rock formations in the Siberian permafrost area during and after the 2020 heat wave" (in en). Proceedings of the National Academy of Sciences 118 (32). doi:10.1073/pnas.2107632118. ISSN 0027-8424. PMID 34341110. Bibcode: 2021PNAS..11807632F. 
  17. ↑ Schuur, E. a. G.; McGuire, A. D.; Schädel, C.; Grosse, G.; Harden, J. W.; Hayes, D. J.; Hugelius, G.; Koven, C. D. et al. (2015). "Climate change and the permafrost carbon feedback" (in en). Nature 520 (7546): 171–179. doi:10.1038/nature14338. ISSN 1476-4687. PMID 25855454. Bibcode: 2015Natur.520..171S. https://www.nature.com/articles/nature14338. 
  18. ↑ Dyonisius, M. N.; Petrenko, V. V.; Smith, A. M.; Hua, Q.; Yang, B.; Schmitt, J.; Beck, J.; Seth, B. et al. (2020-02-21). "Old carbon reservoirs were not important in the deglacial methane budget" (in en). Science 367 (6480): 907–910. doi:10.1126/science.aax0504. ISSN 0036-8075. PMID 32079770. Bibcode: 2020Sci...367..907D. 
  19. ↑ IPCC, 2001: Climate Change 2001: The Scientific Basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change [Houghton, J.T., Y. Ding, D.J. Griggs, M. Noguer, P.J. van der Linden, X. Dai, K. Maskell, and C.A. Johnson (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 881pp.
  20. ↑ N. E. Shakhova; I. P. Semiletov; A. N. Salyuk; N. N. Bel'cheva; D. A. Kosmach (2007). "Methane Anomalies in the Near-Water Atmospheric Layer above the Shelf of East Siberian Arctic Shelf". Doklady Earth Sciences 415 (5): 764–768. doi:10.1134/S1028334X07050236. Bibcode: 2007DokES.415..764S. https://link.springer.com/article/10.1134/S1028334X07050236. 
  21. ↑ Torn, Margaret Susan; Chapin, F.Stuart (1993). "Environmental and biotic controls over methane flux from Arctic tundra" (in en). Chemosphere 26 (1–4): 357–368. doi:10.1016/0045-6535(93)90431-4. Bibcode: 1993Chmsp..26..357T. https://linkinghub.elsevier.com/retrieve/pii/0045653593904314. 
  22. ↑ Whalen, S. C.; Reeburgh, W. S. (1990). "Consumption of atmospheric methane by tundra soils". Nature 346 (6280): 160–162. doi:10.1038/346160a0. Bibcode: 1990Natur.346..160W. http://www.escholarship.org/uc/item/8vs232b0. Retrieved 2019-06-28. 
  23. ↑ Carrington, Damian (July 21, 2020). "First active leak of sea-bed methane discovered in Antarctica". The Guardian. https://www.theguardian.com/environment/2020/jul/22/first-active-leak-of-sea-bed-methane-discovered-in-antarctica. 
  24. ↑ Zimov, Sa; Schuur, Ea; Chapin, Fs 3Rd (June 2006). "Climate change. Permafrost and the global carbon budget.". Science 312 (5780): 1612–3. doi:10.1126/science.1128908. ISSN 0036-8075. PMID 16778046. 
  25. ↑ Shakhova, Natalia (2005). "The distribution of methane on the Siberian Arctic shelves: Implications for the marine methane cycle". Geophysical Research Letters 32 (9): L09601. doi:10.1029/2005GL022751. Bibcode: 2005GeoRL..32.9601S. 
  26. ↑ "Scientists shocked by Arctic permafrost thawing 70 years sooner than predicted" (in en-GB). The Guardian. Reuters. June 18, 2019. ISSN 0261-3077. https://www.theguardian.com/environment/2019/jun/18/arctic-permafrost-canada-science-climate-crisis. 
  27. ↑ Shakhova, Natalia; Semiletov, Igor (2007). "Methane release and coastal environment in the East Siberian Arctic shelf". Journal of Marine Systems 66 (1–4): 227–243. doi:10.1016/j.jmarsys.2006.06.006. Bibcode: 2007JMS....66..227S. 
  28. ↑ Parmentier, F. W.; Thornton, B. F.; Silyakova, A.; Christensen, T. R. (2024). "Vulnerability of Arctic–Boreal methane emissions to climate change". Frontiers in Environmental Science 12. doi:10.3389/fenvs.2024.1460155. Bibcode: 2024FrEnS..1260155P. 
  29. ↑ Brouillette, Monique (2021). "How microbes in permafrost could trigger a massive carbon bomb" (in en). Nature 591 (7850): 360–362. doi:10.1038/d41586-021-00659-y. PMID 33731951. Bibcode: 2021Natur.591..360B. 
  30. ↑ Ruppel, C. (2014). "Permafrost-Associated Gas Hydrate: Is It Really Approximately 1 % of the Global System?". Journal of Chemical & Engineering Data 60 (2): 429–436. doi:10.1021/je500770m. ISSN 0021-9568. http://dx.doi.org/10.1021/je500770m. 
  31. ↑ Zandt, Michiel H.; Liebner, Susanne; Welte, Cornelia U. (2020). "Roles of Thermokarst Lakes in a Warming World". Trends in Microbiology 28 (9): 769–779. doi:10.1016/j.tim.2020.04.002. ISSN 0966-842X. PMID 32362540. 
  32. ↑ Intergovernmental Panel on Climate Change, "IPCC, 2021: Summary for Policymakers", Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (Cambridge: Cambridge University Press), https://www.ipcc.ch/report/ar6/wg1/ 
  33. ↑ Markus Dieser; Erik L J E Broemsen; Karen A Cameron; Gary M King; Amanda Achberger; Kyla Choquette; Birgit Hagedorn; Ron Sletten et al. (2014). "Molecular and biogeochemical evidence for methane cycling beneath the western margin of the Greenland Ice Sheet". The ISME Journal 8 (11): 2305–2316. doi:10.1038/ismej.2014.59. PMID 24739624. Bibcode: 2014ISMEJ...8.2305D. 
  34. ↑ Alexey Portnov; Sunil Vadakkepuliyambatta; Jürgen Mienert; Alun Hubbard (2016). "Ice-sheet-driven methane storage and release in the Arctic". Nature Communications 7. doi:10.1038/ncomms10314. PMID 26739497. Bibcode: 2016NatCo...710314P. 
  35. ↑ "Frost Methane Labs: Design of Smart Micro-Flare Fleet to Mitigate Distributed Methane Emissions". https://arpa-e.energy.gov/technologies/projects/design-smart-micro-flare-fleet-mitigate-distributed-methane-emissions. 
  36. ↑ Herman, Ari (2019-08-26). "A Startup to Save All Startups: Mitigating Arctic Methane Release" (in en). https://ariherman.com/2019/08/26/a-startup-to-save-all-startups/. 
  37. ↑ "Home" (in en). 2021. https://www.frostmethane.com/. 
  38. ↑ Stolaroff, Joshuah K.; Bhattacharyya, Subarna; Smith, Clara A.; Bourcier, William L.; Cameron-Smith, Philip J.; Aines, Roger D. (2012-06-19). "Review of Methane Mitigation Technologies with Application to Rapid Release of Methane from the Arctic" (in en). Environmental Science & Technology 46 (12): 6455–6469. doi:10.1021/es204686w. ISSN 0013-936X. PMID 22594483. Bibcode: 2012EnST...46.6455S. https://pubs.acs.org/doi/10.1021/es204686w. 
  39. ↑ "How to reduce emissions of black carbon and methane in the Arctic" (in en). https://www.arctic-council.org/news/how-to-reduce-emissions-of-black-carbon-and-methane-in-the-arctic/. 



Retrieved from "https://handwiki.org/wiki/index.php?title=Earth:Arctic_methane_emissions&oldid=4179467"