Arctic methane emissions#Contribution to climate change

{{See also|Atmospheric methane|3=Greenhouse gas emissions}}

File:CH4.BRW.Monthly.png (formerly known as Barrow). A peak methane concentration of 1988 parts per billion was reached in October 2019.{{Cite web |last=US Department of Commerce |first=NOAA |title=Global Monitoring Laboratory - Data Visualization |url=https://gml.noaa.gov/dv/iadv/graph.php?code=BRW&program=ccgg&type=ts( |access-date=2024-08-22 |website=gml.noaa.gov |language=EN-US}}]]

File:Thermokarst_failure_of_permafrost.jpg 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.{{Cite web |title=Trends in Atmospheric Methane |url=https://gml.noaa.gov/ccgg/trends_ch4/ |access-date=14 October 2022 |website=NOAA}}

Due to the relatively short lifetime of atmospheric methane (7–12 years compared to 100s of years for CO₂{{Cite web |title=Methane {{!}} Vital Signs |url=https://climate.nasa.gov/vital-signs/methane?intent=121 |access-date=2024-07-20 |website=Climate Change: Vital Signs of the Planet |language=en}}) 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.{{Cite magazine |date=8 February 2022 |title=Scientists raise alarm over 'dangerously fast' growth in atmospheric methane |url=https://www.nature.com/articles/d41586-022-00312-2 |access-date=14 October 2022 |magazine=Nature |vauthors=Tollefson J}} However, there is currently no evidence connecting the Arctic to this recent acceleration.{{Cite journal |vauthors=Jackson RB, Saunois M, Bousquet P, Canadell JG, Poulter B, Stavert AR, Bergamaschi P, Niwa Y, Segers A, Tsuruta A |date=15 July 2020 |title=Increasing anthropogenic methane emissions arise equally from agricultural and fossil fuel sources |journal=Environmental Research Letters |volume=15 |issue=7 |page=071002 |bibcode=2020ERL....15g1002J |doi=10.1088/1748-9326/ab9ed2 |doi-access=free}} 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.{{Cite journal |vauthors=Lan X, Basu S, Schwietzke S, Bruhwiler LM, Dlugokencky EJ, Michel SE, Sherwood OA, Tans PP, Thoning K, Etiope G, Zhuang Q, Liu L, Oh Y, Miller JB, Pétron G, Vaughn BH, Crippa M |date=8 May 2021 |title=Improved Constraints on Global Methane Emissions and Sinks Using δ13C-CH4 |journal=Global Biogeochemical Cycles |volume=35 |issue=6 |pages=e2021GB007000 |bibcode=2021GBioC..3507000L |doi=10.1029/2021GB007000 |pmc=8244052 |pmid=34219915 |doi-access=free}} 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.{{Cite journal |last1=Feng |first1=Liang |last2=Palmer |first2=Paul I. |last3=Zhu |first3=Sihong |last4=Parker |first4=Robert J. |last5=Liu |first5=Yi |date=16 March 2022 |title=Tropical methane emissions explain large fraction of recent changes in global atmospheric methane growth rate |journal=Nature Communications |language=en |volume=13 |issue=1 |page=1378 |bibcode=2022NatCo..13.1378F |doi=10.1038/s41467-022-28989-z |pmc=8927109 |pmid=35297408}}

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.{{cite journal |last1=Rößger |first1=Norman |last2=Sachs |first2=Torsten |last3=Wille |first3=Christian |last4=Boike |first4=Julia |last5=Kutzbach |first5=Lars |date=27 October 2022 |title=Seasonal increase of methane emissions linked to warming in Siberian tundra |url=https://www.researchgate.net/publication/364812576 |journal=Nature Climate Change |volume=12 |issue=11 |pages=1031–1036 |bibcode=2022NatCC..12.1031R |doi=10.1038/s41558-022-01512-4 |s2cid=253192613 |access-date=21 January 2023 |doi-access=free}}

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.{{Cite journal |last1=Walter Anthony |first1=Katey |last2=Daanen |first2=Ronald |last3=Anthony |first3=Peter |last4=Schneider von Deimling |first4=Thomas |last5=Ping |first5=Chien-Lu |last6=Chanton |first6=Jeffrey P. |last7=Grosse |first7=Guido |date=2016 |title=Methane emissions proportional to permafrost carbon thawed in Arctic lakes since the 1950s |url=https://www.nature.com/articles/ngeo2795 |journal=Nature Geoscience |language=en |volume=9 |issue=9 |pages=679–682 |bibcode=2016NatGe...9..679W |doi=10.1038/ngeo2795 |issn=1752-0908 |osti=1776496}} The 2020 heat wave may have released significant methane from carbonate deposits in Siberian permafrost.{{Cite journal |last1=Froitzheim |first1=Nikolaus |last2=Majka |first2=Jaroslaw |last3=Zastrozhnov |first3=Dmitry |date=2021 |title=Methane release from carbonate rock formations in the Siberian permafrost area during and after the 2020 heat wave |journal=Proceedings of the National Academy of Sciences |language=en |volume=118 |issue=32 |bibcode=2021PNAS..11807632F |doi=10.1073/pnas.2107632118 |issn=0027-8424 |pmc=8364203 |pmid=34341110 |doi-access=free}}

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.{{Cite journal |last1=Schuur |first1=E. a. G. |last2=McGuire |first2=A. D. |last3=Schädel |first3=C. |last4=Grosse |first4=G. |last5=Harden |first5=J. W. |last6=Hayes |first6=D. J. |last7=Hugelius |first7=G. |last8=Koven |first8=C. D. |last9=Kuhry |first9=P. |last10=Lawrence |first10=D. M. |last11=Natali |first11=S. M. |date=2015 |title=Climate change and the permafrost carbon feedback |url=https://www.nature.com/articles/nature14338 |journal=Nature |language=en |volume=520 |issue=7546 |pages=171–179 |bibcode=2015Natur.520..171S |doi=10.1038/nature14338 |issn=1476-4687 |pmid=25855454 |s2cid=4460926}} 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.{{Cite journal |last1=Dyonisius |first1=M. N. |last2=Petrenko |first2=V. V. |last3=Smith |first3=A. M. |last4=Hua |first4=Q. |last5=Yang |first5=B. |last6=Schmitt |first6=J. |last7=Beck |first7=J. |last8=Seth |first8=B. |last9=Bock |first9=M. |last10=Hmiel |first10=B. |last11=Vimont |first11=I. |date=2020-02-21 |title=Old carbon reservoirs were not important in the deglacial methane budget |journal=Science |language=en |volume=367 |issue=6480 |pages=907–910 |bibcode=2020Sci...367..907D |doi=10.1126/science.aax0504 |issn=0036-8075 |pmid=32079770 |s2cid=211230350 |doi-access=free}}

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.IPCC, 2001: [https://www.ipcc.ch/report/ar3/wg1/ 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. 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."{{cite journal |author1=N. E. Shakhova |author2=I. P. Semiletov |author3=A. N. Salyuk |author4=N. N. Bel'cheva |author5=D. A. Kosmach |year=2007 |title=Methane Anomalies in the Near-Water Atmospheric Layer above the Shelf of East Siberian Arctic Shelf |url=https://link.springer.com/article/10.1134/S1028334X07050236 |journal=Doklady Earth Sciences |volume=415 |issue=5 |pages=764–768 |bibcode=2007DokES.415..764S |doi=10.1134/S1028334X07050236 |s2cid=129047326|url-access=subscription }} Soil temperature and moisture levels are important variables in soil methane fluxes in tundra environments.{{Cite journal |last1=Torn |first1=Margaret Susan |last2=Chapin |first2=F.Stuart |date=1993 |title=Environmental and biotic controls over methane flux from Arctic tundra |url=https://linkinghub.elsevier.com/retrieve/pii/0045653593904314 |journal=Chemosphere |language=en |volume=26 |issue=1–4 |pages=357–368 |bibcode=1993Chmsp..26..357T |doi=10.1016/0045-6535(93)90431-4|url-access=subscription }}{{Cite journal |last1=Whalen |first1=S. C. |last2=Reeburgh |first2=W. S. |year=1990 |title=Consumption of atmospheric methane by tundra soils |url=http://www.escholarship.org/uc/item/8vs232b0 |url-status=live |journal=Nature |volume=346 |issue=6280 |pages=160–162 |bibcode=1990Natur.346..160W |doi=10.1038/346160a0 |s2cid=4312042 |archive-url=https://web.archive.org/web/20190724154126/https://escholarship.org/uc/item/8vs232b0 |archive-date=2019-07-24 |access-date=2019-06-28}}

{{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,{{cite news |last=Carrington |first=Damian |date=July 21, 2020 |title=First active leak of sea-bed methane discovered in Antarctica |url=https://www.theguardian.com/environment/2020/jul/22/first-active-leak-of-sea-bed-methane-discovered-in-antarctica |newspaper=The Guardian}} thus large releases of methane from these sources may arise as a result of global warming.{{cite journal |author=Zimov, Sa |author2=Schuur, Ea |author3=Chapin, Fs 3Rd |date=June 2006 |title=Climate change. Permafrost and the global carbon budget. |journal=Science |volume=312 |issue=5780 |pages=1612–3 |doi=10.1126/science.1128908 |issn=0036-8075 |pmid=16778046 |s2cid=129667039}}{{cite journal |author=Shakhova, Natalia |year=2005 |title=The distribution of methane on the Siberian Arctic shelves: Implications for the marine methane cycle |journal=Geophysical Research Letters |volume=32 |issue=9 |pages=L09601 |bibcode=2005GeoRL..32.9601S |doi=10.1029/2005GL022751 |doi-access=free}}{{Cite news |date=June 18, 2019 |title=Scientists shocked by Arctic permafrost thawing 70 years sooner than predicted |url=https://www.theguardian.com/environment/2019/jun/18/arctic-permafrost-canada-science-climate-crisis |access-date=2019-07-14 |newspaper=The Guardian |language=en-GB |issn=0261-3077 |agency=Reuters}} Other sources of methane include submarine taliks, river transport, ice complex retreat, submarine permafrost and decaying gas hydrate deposits.{{Cite journal |last1=Shakhova |first1=Natalia |last2=Semiletov |first2=Igor |year=2007 |title=Methane release and coastal environment in the East Siberian Arctic shelf |journal=Journal of Marine Systems |volume=66 |issue=1–4 |pages=227–243 |bibcode=2007JMS....66..227S |citeseerx=10.1.1.371.4677 |doi=10.1016/j.jmarsys.2006.06.006}} Permafrost contains almost twice as much carbon as the atmosphere,{{Cite journal |last=Brouillette |first=Monique |date=2021 |title=How microbes in permafrost could trigger a massive carbon bomb |journal=Nature |language=en |volume=591 |issue=7850 |pages=360–362 |bibcode=2021Natur.591..360B |doi=10.1038/d41586-021-00659-y |pmid=33731951 |s2cid=232297719 |doi-access=free}} with ~20 Gt of permafrost-associated methane trapped in methane clathrates.{{Cite journal |last=Ruppel |first=C. |date=2014 |title=Permafrost-Associated Gas Hydrate: Is It Really Approximately 1 % of the Global System? |url=http://dx.doi.org/10.1021/je500770m |journal=Journal of Chemical & Engineering Data |volume=60 |issue=2 |pages=429–436 |doi=10.1021/je500770m |issn=0021-9568|url-access=subscription }} Permafrost thaw results in the formation of thermokarst lakes in ice-rich yedoma deposits.{{Cite journal |last1=Zandt |first1=Michiel H. |last2=Liebner |first2=Susanne |last3=Welte |first3=Cornelia U. |date=2020 |title=Roles of Thermokarst Lakes in a Warming World |journal=Trends in Microbiology |volume=28 |issue=9 |pages=769–779 |doi=10.1016/j.tim.2020.04.002 |issn=0966-842X |pmid=32362540 |s2cid=218492291 |doi-access=free|hdl=2066/222234 |hdl-access=free }} Methane frozen in permafrost is slowly released as permafrost thaws.{{Citation |last=Intergovernmental Panel on Climate Change |title=IPCC, 2021: Summary for Policymakers |work=Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change |pages= |editor-last= |url=https://www.ipcc.ch/report/ar6/wg1/ |access-date= |place=Cambridge |publisher=Cambridge University Press}}

File:methanestorflaket.JPG chambers used to measure methane and CO₂ emissions in Storflaket peat bog near Abisko, northern Sweden.]]

{{excerpt|Permafrost carbon cycle#Methane emissions}}

{{excerpt|Arctic sea ice decline#Atmospheric chemistry}}

{{excerpt|Clathrate gun hypothesis|paragraphs=1}}

{{excerpt|Clathrate gun hypothesis#Current outlook|paragraphs=2-3}}

{{See also|Greenland ice sheet#Recent 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.{{cite journal|title=Molecular and biogeochemical evidence for methane cycling beneath the western margin of the Greenland Ice Sheet|year=2014|author=Markus Dieser|author2=Erik L J E Broemsen |author3=Karen A Cameron|author4=Gary M King|author5=Amanda Achberger|author6=Kyla Choquette|author7=Birgit Hagedorn|author8=Ron Sletten|author9=Karen Junge |author10=Brent C Christner |name-list-style=amp|journal=The ISME Journal |volume=8 |issue=11|doi=10.1038/ismej.2014.59 |pmid=24739624|pages=2305–2316|pmc=4992074|bibcode=2014ISMEJ...8.2305D }}

A study in 2016 concluded that methane clathrates may exist below Greenland's and Antarctica's ice sheets, based on past evidence.{{Cite journal|title=Ice-sheet-driven methane storage and release in the Arctic |year=2016 |journal=Nature Communications |volume=7 |page=10314 |author=Alexey Portnov|author2=Sunil Vadakkepuliyambatta|author3=Jürgen Mienert |author4=Alun Hubbard |name-list-style=amp |doi=10.1038/ncomms10314 |pmid=26739497 |pmc=4729839 |bibcode=2016NatCo...710314P}}

{{See also|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%).{{Cite book |last=United Nations Environment Programme and Climate and Clean Air Coalition |title=Global Methane Assessment: Benefits and Costs of Mitigating Methane Emissions. |publisher=Nairobi: United Nations Environment Programme. |year=2021 |isbn=9789280738544 |location=Nairobi}} 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.

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.{{Cite journal |last1=Sun |first1=Tianyi |last2=Ocko |first2=Ilissa B |last3=Hamburg |first3=Steven P |date=2022-03-15 |title=The value of early methane mitigation in preserving Arctic summer sea ice |journal=Environmental Research Letters |language=en |volume=17 |issue=4 |pages=044001 |bibcode=2022ERL....17d4001S |doi=10.1088/1748-9326/ac4f10 |issn=1748-9326 |s2cid=247472086 |doi-access=free}}

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.{{Cite web |title=Frost Methane Labs: Design of Smart Micro-Flare Fleet to Mitigate Distributed Methane Emissions |url=https://arpa-e.energy.gov/technologies/projects/design-smart-micro-flare-fleet-mitigate-distributed-methane-emissions |access-date=2022-07-24 |website=ARPA-E}}{{Cite web |last=Herman |first=Ari |date=2019-08-26 |title=A Startup to Save All Startups: Mitigating Arctic Methane Release |url=https://ariherman.com/2019/08/26/a-startup-to-save-all-startups/ |access-date=2022-07-24 |website=The LegoBox Travelogue |language=en}}{{Cite web |date=2021 |title=Home |url=https://www.frostmethane.com/ |access-date=2022-07-24 |website=Frost Methane Labs |language=en}}

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.{{Cite journal |last1=Stolaroff |first1=Joshuah K. |last2=Bhattacharyya |first2=Subarna |last3=Smith |first3=Clara A. |last4=Bourcier |first4=William L. |last5=Cameron-Smith |first5=Philip J. |last6=Aines |first6=Roger D. |date=2012-06-19 |title=Review of Methane Mitigation Technologies with Application to Rapid Release of Methane from the Arctic |url=https://pubs.acs.org/doi/10.1021/es204686w |journal=Environmental Science & Technology |language=en |volume=46 |issue=12 |pages=6455–6469 |doi=10.1021/es204686w |pmid=22594483 |bibcode=2012EnST...46.6455S |osti=1773262 |issn=0013-936X}}

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.{{Cite web |title=How to reduce emissions of black carbon and methane in the Arctic |url=https://www.arctic-council.org/news/how-to-reduce-emissions-of-black-carbon-and-methane-in-the-arctic/ |access-date=2022-07-24 |website=Arctic Council |language=en}}

{{Portal|Global warming|Ecology|Environment}}

• {{annotated link|Arctic dipole anomaly}}
• {{annotated link|Climate change in Antarctica}}
• {{annotated link|Effects of climate change}}
• {{annotated link|Global Carbon Project}}
• {{annotated link|Global Methane Initiative}}
• {{annotated link|Peat}}

{{reflist|30em}}

• [https://web.archive.org/web/20190814091633/https://www.nationalgeographic.com/environment/2019/08/arctic-permafrost-is-thawing-it-could-speed-up-climate-change-feature/ Arctic permafrost is thawing fast. That affects us all.] National Geographic, 2019
• [http://www.bbc.com/future/story/20190822-why-is-the-arctic-on-fire?ocid=fbfut Why the Arctic is smouldering], BBC Future, by Zoe Cormier, 2019

{{Arctic topics}}

{{climate change}}

{{Periglacial environment}}

{{DEFAULTSORT:Arctic Methane Release}}

Category:Arctic Ocean

Category:Climate change feedbacks

Category:Effects of climate change

Category:Environment of the Arctic

Category:Methane

Category:Permafrost

Category:Greenhouse gas emissions