Editing Peat (section)

==Environmental and ecological issues==
[[File:Co2.recent.ch.png|thumb|Increase, and change relative to previous year, of the atmospheric concentration of [[carbon dioxide]]]]

The distinctive ecological conditions of peat wetlands provide a habitat for distinctive fauna and flora. For example, [[whooping cranes]] nest in North American peatlands, whilst [[Siberian crane]]s nest in the West Siberian peatland. [[Palsa]] mires have a rich bird life and are an EU-red listed habitat,<ref>{{Cite journal| doi = 10.1017/S0376892904001018| volume = 31| issue = 1| pages = 30–37| last1 = Luoto| first1 = Miska| last2 = Heikkinen| first2 = Risto K.| last3 = Carter| first3 = Timothy R.| title = Loss of palsa mires in Europe and biological consequences| journal = Environmental Conservation| access-date = 2022-03-04| date = 2004| bibcode = 2004EnvCo..31...30L| s2cid = 86157282| url = https://www.cambridge.org/core/journals/environmental-conservation/article/loss-of-palsa-mires-in-europe-and-biological-consequences/C704EC2EF3CD217FF7D6E1567A92008F#}}</ref> and in Canada riparian peat banks are used as maternity sites for polar bears.<ref>{{Cite journal| volume = 83| issue = 6| pages = 860| last1 = Richardson| first1 = Evan| last2 = Stirling| first2 = Ian| last3 = Hik| first3 = David S.| title = Polar bear (Ursus maritimus) maternity denning habitat in western Hudson Bay: a bottom-up approach to resource selection functions| journal = Canadian Journal of Zoology| access-date = 2023-07-31| date = 2005| doi = 10.1139/z05-075| bibcode = 2005CaJZ...83..860R| url = https://www.academia.edu/4675165}}</ref> Natural peatlands also have many species of wild orchids and carnivorous plants. For more on biological communities, see [[wetland]], [[bog]] or [[fen]].

Around half of the area of northern peatlands is [[permafrost]]-affected, and this area represents around a tenth of the total permafrost area, and also a tenth (185 ± 66 Gt) of all permafrost carbon, equivalent to around half of the carbon stored in the atmosphere.<ref name="Hugelius- 2020">{{Cite journal| doi = 10.1073/pnas.1916387117| issn = 0027-8424| volume = 117| issue = 34| pages = 20438–20446| last1 = Hugelius| first1 = Gustaf| last2 = Loisel| first2 = Julie| last3 = Chadburn| first3 = Sarah| last4 = Jackson| first4 = Robert B.| last5 = Jones| first5 = Miriam| last6 = MacDonald| first6 = Glen| last7 = Marushchak| first7 = Maija| last8 = Olefeldt| first8 = David| last9 = Packalen| first9 = Maara| last10 = Siewert| first10 = Matthias B.| last11 = Treat| first11 = Claire| last12 = Turetsky| first12 = Merritt| last13 = Voigt| first13 = Carolina| last14 = Yu| first14 = Zicheng| title = Large stocks of peatland carbon and nitrogen are vulnerable to permafrost thaw| journal = Proceedings of the National Academy of Sciences| date = 2020-08-25| pmid = 32778585| pmc = 7456150| doi-access = free| bibcode = 2020PNAS..11720438H}}</ref><ref name="ReferenceA">{{Cite journal |last1=Tarnocai |first1=C. |last2=Canadell |first2=J. G. |last3=Schuur |first3=E. A. G. |last4=Kuhry |first4=P. |last5=Mazhitova |first5=G. |last6=Zimov |first6=S. |date=2009 |title=Soil organic carbon pools in the northern circumpolar permafrost region |journal=Global Biogeochemical Cycles |volume=23 |issue=2 |bibcode=2009GBioC..23.2023T |doi=10.1029/2008GB003327 |issn=1944-9224 |doi-access=free}}</ref><ref name="science.sciencemag.org">{{Cite journal |last1=Zimov |first1=Sergey A. |last2=Schuur |first2=Edward A. G. |last3=Chapin |first3=F. Stuart III |name-list-style=and |date=2006-06-16 |title=Permafrost and the Global Carbon Budget |url=https://science.sciencemag.org/content/312/5780/1612 |journal=Science |volume=312 |issue=5780 |pages=1612–1613 |doi=10.1126/science.1128908 |issn=0036-8075 |pmid=16778046 |s2cid=129667039 |access-date=2020-02-14}}</ref> Dry peat is a good insulator (with a thermal conductivity of around 0.25 Wm<sup>−1</sup>K<sup>−1</sup>) and therefore plays an important role in protecting permafrost from thaw.<ref>{{Cite journal| doi = 10.1016/j.coldregions.2007.08.002| issn = 0165-232X| volume = 52| issue = 3| pages = 408–414| last1 = Kujala| first1 = Kauko| last2 = Seppälä| first2 = Matti| last3 = Holappa| first3 = Teuvo| title = Physical properties of peat and palsa formation| journal = Cold Regions Science and Technology| access-date = 2023-07-03| date = 2008-05-01| bibcode = 2008CRST...52..408K| url = https://www.sciencedirect.com/science/article/pii/S0165232X07001644}}</ref> The insulating effect of dry peat also makes it integral to unique permafrost landforms such as [[palsa]]s and permafrost peat plateaus.<ref name="ReferenceA"/><ref name="science.sciencemag.org"/><ref>{{Cite journal| doi = 10.2307/521453| issn = 0435-3676| volume = 68| issue = 3| pages = 141–147| last = Seppälä| first = Matti| title = The Origin of Palsas| journal = Geografiska Annaler: Series A, Physical Geography| access-date = 2020-10-22| date = 1986| url = https://www.jstor.org/stable/521453| jstor = 521453}}</ref> Peatland permafrost thaw tends to result in an increase in [[methane emissions]] and a small increase in [[carbon dioxide]] uptake, meaning that it contributes to the [[permafrost carbon cycle|permafrost carbon feedback]].<ref>{{Cite journal| doi = 10.1111/j.1365-2486.2006.01267.x| issn = 1365-2486| volume = 12| issue = 12| pages = 2352–2369| last1 = Johansson| first1 = Torbjörn| last2 = Malmer| first2 = Nils| last3 = Crill| first3 = Patrick M.| last4 = Friborg| first4 = Thomas| last5 = Åkerman| first5 = Jonas H.| last6 = Mastepanov| first6 = Mikhail| last7 = Christensen| first7 = Torben R.| title = Decadal vegetation changes in a northern peatland, greenhouse gas fluxes and net radiative forcing| journal = Global Change Biology| access-date = 2021-08-11| date = 2006| bibcode = 2006GCBio..12.2352J| s2cid = 34813903| url = https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2486.2006.01267.x}}</ref><ref>{{Cite journal| doi = 10.5194/bg-7-95-2010| issn = 1726-4170| volume = 7| issue = 1| pages = 95–108| last1 = Bäckstrand| first1 = K.| last2 = Crill| first2 = P. M.| last3 = Jackowicz-Korczyñski| first3 = M.| last4 = Mastepanov| first4 = M.| last5 = Christensen| first5 = T. R.| last6 = Bastviken| first6 = D.| title = Annual carbon gas budget for a subarctic peatland, Northern Sweden| journal = Biogeosciences| access-date = 2021-08-11| date = 2010-01-11| url = https://bg.copernicus.org/articles/7/95/2010/| doi-access = free| bibcode = 2010BGeo....7...95B}}</ref><ref>{{Cite journal| doi = 10.1029/2003GL018680| issn = 1944-8007| volume = 31| issue = 4| last1 = Christensen| first1 = Torben R.| last2 = Johansson| first2 = Torbjörn| last3 = Åkerman| first3 = H. Jonas| last4 = Mastepanov| first4 = Mihail| last5 = Malmer| first5 = Nils| last6 = Friborg| first6 = Thomas| last7 = Crill| first7 = Patrick| last8 = Svensson| first8 = Bo H.| title = Thawing sub-arctic permafrost: Effects on vegetation and methane emissions| journal = Geophysical Research Letters| date = 2004| s2cid = 129023294| doi-access = free| bibcode = 2004GeoRL..31.4501C}}</ref> Under 2&nbsp;°C [[global warming]], 0.7 million km<sup>2</sup> of peatland permafrost could thaw, and with warming of +1.5 to 6&nbsp;°C a cumulative 0.7 to 3 PgC of methane could be released as a result of permafrost peatland thaw by 2100.<ref name="Hugelius- 2020"/> The forcing from these potential emissions would be approximately equivalent to 1% of projected anthropogenic emissions.

One characteristic of peat is the bioaccumulation of metals concentrated in the peat. Accumulated mercury is of significant environmental concern.<ref>{{Cite journal|author1=Mitchell, Carla P. J. |author2=Branfireun, Brian A. |author3=Kolka, Randall K. |name-list-style=amp |year=2008|title=Spatial Characteristics of Net Methylmercury Production Hot Spots in Peatlands|journal=Environmental Science and Technology|publisher=American Chemical Society|volume=42|number=4|pages=1010–1016|url=http://www.nrs.fs.fed.us/pubs/jrnl/2008/nrs_2008_mitchell_001.pdf|archive-url=https://web.archive.org/web/20081031163040/http://www.nrs.fs.fed.us/pubs/jrnl/2008/nrs_2008_mitchell_001.pdf|archive-date=31 October 2008|url-status=live|doi=10.1021/es0704986|pmid=18351065 |bibcode=2008EnST...42.1010M}}</ref>

===Peat drainage===
Large areas of organic wetland (peat) soils are currently drained for agriculture, forestry and peat extraction (i.e. through canals<ref>{{Cite web|url=http://www.borneonaturefoundation.org/en/saving-the-rainforest/canal-blocking/|title=Peatland drainage through canals|access-date=2020-11-23|archive-date=2020-11-28|archive-url=https://web.archive.org/web/20201128231248/http://www.borneonaturefoundation.org/en/saving-the-rainforest/canal-blocking/|url-status=dead}}</ref>). This process is taking place all over the world. This not only destroys the habitat of many species but also heavily fuels climate change.<ref>{{Cite web|url=https://www.iucn.org/resources/issues-briefs/peatlands-and-climate-change|title=Peatlands and climate change|date=2017-11-06|website=IUCN|language=en|access-date=2020-01-23}}</ref> As a result of peat drainage, the organic carbon—which built over thousands of years and is normally underwater—is suddenly exposed to the air. It decomposes and turns into [[carbon dioxide]] ({{CO2}}), which is released into the atmosphere.<ref>[https://qualitywatertreatment.com/pages/saving-peatlands-their-carbon-nature Content from Wetlands.org], Wetlands International | Peatlands and CO<sub>2</sub> Emissions</ref> The global {{CO2}} emissions from drained peatlands have increased from 1,058 Mton in 1990 to 1,298 Mton in 2008 (a 20% increase). This increase has particularly taken place in developing countries, of which [[Indonesia]], [[Malaysia]] and [[Papua New Guinea]] are the fastest-growing top emitters. This estimate excludes [[emissions from peat fires]] (conservative estimates amount to at least 4,000 Mton/{{CO2}}-eq./yr for south-east Asia). With 174 Mton/{{CO2}}-eq./yr, the EU is after Indonesia (500 Mton) and before Russia (161 Mton), the world's second-largest emitter of drainage-related peatland {{CO2}} (excl. extracted peat and fires). Total {{CO2}} emissions from the worldwide 500,000&nbsp;km<sup>2</sup> of degraded peatland may exceed 2.0 Gtons (including emissions from peat fires), which is almost 6% of all global carbon emissions.<ref>[http://www.wetlands.org/peatco2 Wetlands.org]{{dead link|date=December 2017 |bot=InternetArchiveBot |fix-attempted=yes }}, The Global Peat CO2 Picture, Wetlands International and Greifswald University, 2010</ref>{{Obsolete source|reason=This source is old and needs update |date=November 2023}}

==={{anchor|Fires|Peat Fires}} Peat fires===
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{{See also|Slash and burn|Stubble burning|Arctic methane release}}
[[File:TOMS indonesia smog lrg.jpg|thumb|Smoke and ozone pollution from [[Indonesia]]n fires, 1997]]
Peat can be a major fire hazard and is not extinguished by light rain.<ref>{{Cite journal |last1=Lin |first1=Shaorun |last2=Cheung |first2=Yau Kuen |last3=Xiao |first3=Yang |last4=Huang |first4=Xinyan |date=2020-07-20 |title=Can rain suppress smoldering peat fire? |url=http://www.sciencedirect.com/science/article/pii/S0048969720319811 |journal=Science of the Total Environment |language=en |volume=727 |page=138468 |bibcode=2020ScTEn.72738468L |doi=10.1016/j.scitotenv.2020.138468 |issn=0048-9697 |pmid=32334212 |s2cid=216146063 |hdl=10397/89496|hdl-access=free }}</ref> Peat fires may burn for great lengths of time, or [[Smouldering|smoulder]] underground and reignite after winter if an oxygen source is present.

Peat has a high carbon content and can burn under low moisture conditions. Once ignited by the presence of a heat source (e.g., a [[wildfire]] penetrating the subsurface), it smoulders. These smouldering fires can burn undetected for very long periods of time (months, years, and even centuries) propagating in a creeping fashion through the underground peat layer.

Despite the damage that the burning of raw peat can cause, bogs are naturally subject to wildfires and depend on the wildfires to keep woody competition from lowering the water table and shading out many bog plants. Several families of plants including the carnivorous ''[[Sarracenia]]'' (trumpet pitcher), [[Dionaea (plant)|''Dionaea'']] (Venus flytrap), ''[[Utricularia]]'' (bladderworts) and non-carnivorous plants such as the [[Lilium pyrophilum|sandhills lily]], [[Ctenium aromaticum|toothache grass]] and many species of orchid are now threatened and in some cases endangered from the combined forces of human drainage, negligence and absence of fire.<ref>{{cite web|url=http://www.pitcherplant.org/|title=Meadowview Biological Research Station – Preserving and Restoring Pitcher Plant Bogs|author=Michael Kevin Smith|access-date=25 October 2015}}</ref><ref>{{cite web|url=http://www.unc.edu/news/archives/may03/lilly050903.html|title=New lily species found in eastern N.C. Sandhills|access-date=25 October 2015}}</ref><ref>[http://www.dmr.state.ms.us/Coastal-Ecology/preserves/plants/grasses-sedges-rushes/toothache-grass/toothache-grass.htm toothache-grass] ''www.dmr.state.ms.us''{{dead link|date=March 2018 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

The recent burning of peat bogs in Indonesia, with their large and deep growths containing more than {{Convert|50|e9t|e9ST e9LT|abbr=off}} of carbon, has contributed to increases in world [[carbon dioxide]] levels.<ref>{{Cite web|url=https://www.scientificamerican.com/article/vast-peat-fires-threaten-health-and-boost-global-warming/|title=Vast Peat Fires Threaten Health and Boost Global Warming|last=Lim|first=XiaoZhi|website=Scientific American|language=en|access-date=2019-08-16}}</ref> Peat deposits in Southeast Asia could be destroyed by 2040.<ref>{{cite news| url=http://news.bbc.co.uk/2/hi/science/nature/4208564.stm | work=BBC News | title=Asian peat fires add to warming | date=2005-09-03 | access-date=2010-05-22}}</ref><ref>{{cite book |author=Joel S. Levine |title=Wildland fires and the environment: a global synthesis |url=https://books.google.com/books?id=NLSPnDrb0LsC |access-date=9 May 2011 |date= 1999 |publisher=UNEP/Earthprint |isbn=978-92-807-1742-6 }} [http://asd-www.larc.nasa.gov/biomass_burn/wildland.html web link] {{webarchive|url=https://web.archive.org/web/20050902225846/http://asd-www.larc.nasa.gov/biomass_burn/wildland.html |date=2005-09-02 }}</ref>

It is estimated that in 1997, [[1997 Southeast Asian haze|peat and forest fires in Indonesia]] released between {{Convert|0.81 and 2.57|Gt|e9ST e9LT|abbr=off}} of carbon; equivalent to 13–40 percent of the amount released by global fossil fuel burning, and greater than the carbon uptake of the world's biosphere. These fires may be responsible for the acceleration in the increase in carbon dioxide levels since 1998.<ref>Cat Lazaroff, [http://www.ens-newswire.com/ens/nov2002/2002-11-08-06.asp Indonesian Wildfires Accelerated Global Warming] {{Webarchive|url=https://web.archive.org/web/20190908133919/http://www.ens-newswire.com/ens/nov2002/2002-11-08-06.asp |date=2019-09-08 }}, Environment News Service</ref><ref>Fred Pearce [https://www.newscientist.com/article/dn6613-massive-peat-burn-is-speeding-climate-change/ Massive peat burn is speeding climate change], New Scientist, 6 November 2004</ref> More than 100 peat fires in [[Kalimantan]] and East [[Sumatra]] have continued to burn since 1997; each year, these peat fires ignite new forest fires above the ground.

In North America, peat fires can occur during severe droughts throughout their occurrence, from boreal forests in Canada to swamps and fens in the subtropical southern Florida [[Everglades]].<ref>{{cite web |title=Florida Everglades |url=http://sofia.usgs.gov/publications/circular/1182/ |publisher=U.S. Geological Survey |access-date=11 June 2013 |date=15 January 2013 |archive-date=26 June 2008 |archive-url=https://web.archive.org/web/20080626081529/http://sofia.usgs.gov/publications/circular/1182/|url-status=dead}}</ref> Once a fire has burnt through the area, hollows in the peat are burnt out, and hummocks are desiccated but can contribute to ''Sphagnum'' recolonization.<ref>{{Cite journal |first1=Nicole |last1=Fenton |first2=Nicolas |last2=Lecomte |first3=Sonia |last3=Légaré |name-list-style=amp |first4=Yves |last4=Bergeron |title=Paludification in black spruce (''Picea mariana'') forests of eastern Canada: Potential factors and management implications |journal=Forest Ecology and Management |volume=213 |issue=1–3 |year=2005 |pages=151–159 |doi=10.1016/j.foreco.2005.03.017 |bibcode=2005ForEM.213..151F }}</ref>

In the summer of 2010, an unusually high [[2010 Northern Hemisphere summer heat wave|heat wave]] of up to {{cvt|40|C}} ignited large deposits of peat in Central Russia, [[2010 Russian wildfires|burning thousands of houses]] and covering the capital of Moscow with a toxic [[smog|smoke blanket]]. The situation remained critical until the end of August 2010.<ref>{{Cite news |url=https://www.bbc.co.uk/news/world-europe-10762921 |title=Fog from peat fires blankets Moscow amid heat wave |work=BBC |date=26 July 2010 }}</ref><ref>{{Cite news |url=http://seattletimes.nwsource.com/html/nationworld/2012486819_apeurussiafires.html |title=Russia begins to localize fires, others rage |agency=Associated Press |date= 30 July 2010}}</ref>

In June 2019, despite some [[Wildfire#Prevention|forest fire prevention methods]] being put in place, peat fires<ref>{{Cite web|url=https://www.usatoday.com/story/news/weather/2019/07/23/arctic-fires-shown-satellite-concerning-scientists/1793530001/|title=Thanks to climate change, parts of the Arctic are on fire. Scientists are concerned|first=Morgan|last=Hines|website=USA Today}}</ref> in the Arctic emitted {{Convert|50|Mt|e6ST e6LT|abbr=off}} of CO<sub>2</sub>, which is equal to Sweden's total annual emissions.<ref>{{Cite web|url=http://www.theguardian.com/world/2019/jul/26/unprecedented-more-than-100-wildfires-burning-in-the-arctic-in-worst-ever-season|title='Unprecedented': more than 100 Arctic wildfires burn in worst ever season|date=July 26, 2019|website=The Guardian}}</ref> The peat fires are linked to climate change, as they are much more likely to occur nowadays due to this effect.<ref>{{Cite web|url=http://www.bbc.com/future/story/20190822-why-is-the-arctic-on-fire|title=Why the Arctic is smouldering|last=Cormier|first=Zoe|website=bbc.com|date=27 August 2019 |language=en|access-date=2019-08-28}}</ref><ref>{{Cite journal|last1=Turetsky|first1=Merritt R.|last2=Benscoter|first2=Brian|last3=Page|first3=Susan|last4=Rein|first4=Guillermo|last5=van der Werf|first5=Guido R.|last6=Watts|first6=Adam|date=2014-12-23|title=Global vulnerability of peatlands to fire and carbon loss|url=https://www.nature.com/articles/ngeo2325.epdf|journal=Nature Geoscience|language=en|volume=8|issue=1|pages=11–14|doi=10.1038/ngeo2325|issn=1752-0894|hdl=10044/1/21250|hdl-access=free}}</ref>[[File:Peat haggs at start of Allt Lagan a' Bhainne tributary on Eilrig - geograph.org.uk - 1420692.jpg|thumb|Peat hags in the Scottish Highlands]]

=== Erosion: Peat hags ===
Peat "hags" are a form of erosion that occur at the sides of gullies that cut into the peat; they sometimes also occur in isolation.<ref name="YPP">[http://www.yppartnership.org.uk/restoration/peat-hags/ ''Peat Hags''] {{Webarchive|url=https://web.archive.org/web/20160712032305/http://www.yppartnership.org.uk/restoration/peat-hags/|date=2016-07-12}} at www.yppartnership.org.uk, website of the Yorkshire Peat Partnership. Accessed 9 July 2016.</ref> Hags may result when flowing water cuts downwards into the peat and when fire or [[overgrazing]] exposes the peat surface. Once the peat is exposed in these ways, it is prone to further erosion by wind, water and livestock. The result is overhanging vegetation and peat. Hags are too steep and unstable for vegetation to establish itself, so they continue to erode unless restorative action is taken.<ref name="YPP"/>