Earth:Arctic methane emissions

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Short description: Release of methane from seas and soils in permafrost regions of the Arctic
Arctic methane concentrations in the atmosphere up to September 2020. A peak of 1988 parts per billion was reached in October 2019.

Arctic methane release is the release of methane from Arctic ocean waters as well as from soils in permafrost regions of the Arctic. While it is a long-term natural process, methane release is exacerbated by global warming. This results in a positive climate change feedback (meaning one that amplifies warming), as methane is itself a powerful greenhouse gas.[1][2] The Arctic region is one of the many natural sources of the greenhouse gas methane.[3] Global warming could potentially accelerate its release, due to both release of methane from existing stores, and from methanogenesis in rotting biomass.[4]

Large quantities of methane are stored in the Arctic in natural gas deposits and as undersea clathrates. When permafrost thaws as a consequence of warming, large amounts of organic material can become available for methanogenesis and may ultimately be released as methane. Clathrates also degrade on warming and release methane directly.[5][6][7][8]

Atmospheric methane concentrations are 8–10% higher in the Arctic than in the Antarctic atmosphere. During cold glacier epochs, this gradient decreases to practically insignificant levels.[9] Land ecosystems are considered the main sources of this asymmetry, although it has been suggested in 2007 that "the role of the Arctic Ocean is significantly underestimated."[10] Soil temperature and moisture levels have been found to be significant variables in soil methane fluxes in tundra environments.[11][12]

Sources of methane

Thawing permafrost

PMMA chambers used to measure methane and CO2 emissions in Storflaket peat bog near Abisko, northern Sweden.

Arctic sea ice decline

Main page: Physics:Arctic sea ice decline

A 2015 study concluded that Arctic sea ice decline accelerates methane emissions from the Arctic tundra, with the emissions for 2005-2010 being around 1.7 million tonnes higher than they would have been with the sea ice at 1981–1990 levels.[13] One of the researchers noted, "The expectation is that with further sea ice decline, temperatures in the Arctic will continue to rise, and so will methane emissions from northern wetlands."[14]

Clathrate breakdown

Greenland ice sheet

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. 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 4 months of the summer melt season was estimated at 990 Mg CH4. Because the Russell-Leverett Glacier is representative of similar Greenland outlet glaciers, the researchers concluded that the Greenland Ice Sheet may represent a significant global methane source.[15] A study in 2016 concluded that methane clathrates may exist below Greenland's and Antarctica's ice sheets, based on past evidence.[16]

Contributions to climate change

Main sources of global methane emissions (2008-2017) according to the Global Carbon Project[17]

Due to the relatively short lifetime of atmospheric methane, its global trends are more complex than those of carbon dioxide. NOAA annual records have been updated since 1984, and 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 a consistent acceleration in annual methane increases, 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.[18]

These trends alarm climate scientists, with some suggesting that they represent a climate change feedback increasing natural methane emissions well beyond their preindustrial levels.[19] However, there is currently no evidence connecting the Arctic to this recent acceleration.[20] In fact, a 2021 study indicated that the role of the Arctic was typically overerestimated in global methane accounting, while the role of tropical regions was consistently underestimated.[21] 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.[22]

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.[23]

Reducing methane emissions

See also: Climate change mitigationTemplate:Carbon cycle

Mitigation of methane emissions has greatest potential to preserve Arctic sea ice if it is implemented within the 2020s.[24]

Use of flares

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.[25][26][27]

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.[28]

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.[29]

See also


References

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  2. Christensen, Torben Røjle; Arora, Vivek K.; Gauss, Michael; Höglund-Isaksson, Lena; Parmentier, Frans-Jan W. (4 February 2019). "Christensen". Scientific Reports 9 (1): 1146. doi:10.1038/s41598-018-37719-9. PMID 30718695. 
  3. 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. Bibcode2010Sci...327..322B. https://authors.library.caltech.edu/57435/2/Bloom.SOM.pdf. Retrieved 2019-12-03. 
  4. Walter, K. M.; Chanton, J. P.; Chapin, F. S.; Schuur, E. A. G.; Zimov, S. A. (2008). "Methane production and bubble emissions from arctic lakes: Isotopic implications for source pathways and ages". Journal of Geophysical Research 113: G00A08. doi:10.1029/2007JG000569. Bibcode2008JGRG..11300A08W. https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2007JG000569. 
  5. 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. 
  6. 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. Bibcode2005GeoRL..32.9601S. 
  7. 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. Bibcode2007JMS....66..227S. https://www.sciencedirect.com/science/article/abs/pii/S0924796306001874. 
  8. Sayedi, Sayedeh Sara; Abbott, Benjamin W; Thornton, Brett F; Frederick, Jennifer M; Vonk, Jorien E; Overduin, Paul; Schädel, Christina; Schuur, Edward A G et al. (2020-12-01). "Subsea permafrost carbon stocks and climate change sensitivity estimated by expert assessment". Environmental Research Letters 15 (12): B027-08. doi:10.1088/1748-9326/abcc29. ISSN 1748-9326. Bibcode2020AGUFMB027...08S. 
  9. Climate Change 2001: The Scientific Basis (Cambridge Univ. Press, Cambridge, 2001)
  10. 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. Bibcode2007DokES.415..764S. https://link.springer.com/article/10.1134/S1028334X07050236. 
  11. Torn, M.; Chapiniii, F. (1993). "Environmental and biotic controls over methane flux from Arctic tundra". Chemosphere 26 (1–4): 357–368. doi:10.1016/0045-6535(93)90431-4. Bibcode1993Chmsp..26..357T. https://www.sciencedirect.com/science/article/abs/pii/0045653593904314. 
  12. Whalen, S. C.; Reeburgh, W. S. (1990). "Consumption of atmospheric methane by tundra soils". Nature 346 (6280): 160–162. doi:10.1038/346160a0. Bibcode1990Natur.346..160W. http://www.escholarship.org/uc/item/8vs232b0. Retrieved 2019-06-28. 
  13. Parmentier, Frans-Jan W.; Zhang, Wenxin; Mi, Yanjiao; Zhu, Xudong; van Huissteden, Jacobus; J. Hayes, Daniel; Zhuang, Qianlai; Christensen, Torben R. et al. (25 July 2015). "Rising methane emissions from northern wetlands associated with sea ice decline". Geophysical Research Letters 42 (17): 7214–7222. doi:10.1002/2015GL065013. PMID 27667870. Bibcode2015GeoRL..42.7214P. 
  14. "Melting Arctic sea ice accelerates methane emissions". 2015. https://www.sciencedaily.com/releases/2015/09/150917091306.htm. 
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  16. Alexey Portnov; Sunil Vadakkepuliyambatta; Jürgen Mienert; Alun Hubbard (2016). "Ice-sheet-driven methane storage and release in the Arctic". Nature Communications 7: 10314. doi:10.1038/ncomms10314. PMID 26739497. Bibcode2016NatCo...710314P. 
  17. Saunois, M. et al. (July 15, 2020). "The Global Methane Budget 2000–2017" (in en). Earth System Science Data (ESSD) 12 (3): 1561–1623. doi:10.5194/essd-12-1561-2020. ISSN 1866-3508. Bibcode2020ESSD...12.1561S. https://essd.copernicus.org/articles/12/1561/2020/. Retrieved 28 August 2020. 
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  19. "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. 
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  21. "Improved Constraints on Global Methane Emissions and Sinks Using δ13C-CH4". Global Biogeochemical Cycles 35 (6): e2021GB007000. 8 May 2021. doi:10.1029/2021GB007000. PMID 34219915. Bibcode2021GBioC..3507000L. 
  22. 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. Bibcode2022NatCo..13.1378F. 
  23. 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. Bibcode2022NatCC..12.1031R. https://www.researchgate.net/publication/364812576. Retrieved 21 January 2023. 
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  25. "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. 
  26. 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/. 
  27. "Home" (in en). 2021. https://www.frostmethane.com/. 
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External links