Editing Permafrost (section)

=== Thaw-induced ground instability ===
[[File:Permafrost coastal erosion USGS.png|thumb|Severe [[coastal erosion]] on the Arctic Ocean coast of [[Alaska]].]]
[[File:Permafrost revealed by coastal erosion (9354).jpg|thumb|Permafrost revealed by coastal erosion in Alaska.]]
As the water drains or evaporates, soil structure weakens and sometimes becomes viscous until it regains strength with decreasing moisture content. One visible sign of permafrost degradation is the [[Drunken trees|random displacement of trees from their vertical orientation]] in permafrost areas.<ref>{{Cite book|last=Huissteden|first=J. van|url=https://books.google.com/books?id=mZPHDwAAQBAJ&q=permafrost+thaw|title=Thawing Permafrost: Permafrost Carbon in a Warming Arctic|date=2020|publisher=Springer Nature|isbn=978-3-030-31379-1|page=296 }}</ref> Global warming has been increasing permafrost slope disturbances and sediment supplies to fluvial systems, resulting in exceptional increases in river sediment.<ref>{{cite journal |last1=Li |first1=Dongfeng |last2=Lu |first2=Xixi |last3=Overeem |first3=Irina |last4=Walling |first4=Desmond E. |last5=Syvitski |first5=Jaia |last6=Kettner |first6=Albert J. |last7=Bookhagen |first7=Bodo |last8=Zhou |first8=Yinjun |last9=Zhang |first9=Ting |title=Exceptional increases in fluvial sediment fluxes in a warmer and wetter High Mountain Asia |journal=Science |date=29 October 2021 |volume=374 |issue=6567 |pages=599–603 |doi=10.1126/science.abi9649 |pmid=34709922 |bibcode=2021Sci...374..599L |s2cid=240152765 }}</ref> On the other hands, disturbance of formerly hard soil increases drainage of water reservoirs in northern [[wetland]]s. This can dry them out and compromise the survival of plants and animals used to the wetland ecosystem.<ref>{{Cite journal|last1=Koven|first1=Charles D.|last2=Riley|first2=William J.|last3=Stern|first3=Alex|date=2012-10-01|title=Analysis of Permafrost Thermal Dynamics and Response to Climate Change in the CMIP5 Earth System Models|journal=Journal of Climate|volume=26|issue=6|pages=1877–1900|doi=10.1175/JCLI-D-12-00228.1|osti=1172703 |url=http://www.escholarship.org/uc/item/9cv093s8|doi-access=free}}</ref>

In high mountains, much of the structural stability can be attributed to [[glacier]]s and permafrost.<ref>{{Cite journal |last1=Huggel |first1=C. |last2=Allen |first2=S. |last3=Deline |first3=P. |title=Ice thawing, mountains falling; are alpine rock slope failures increasing? |journal=Geology Today |volume=28 |issue=3 |pages=98–104 |date=June 2012 |doi=10.1111/j.1365-2451.2012.00836.x |bibcode=2012GeolT..28...98H |s2cid=128619284 }}</ref> As climate warms, permafrost thaws, decreasing slope stability and increasing stress through buildup of [[pore-water]] pressure, which may ultimately lead to slope failure and [[rockfall]]s.<ref>{{cite book|last1=Nater|first1=P.|last2=Arenson|first2=L.U.|last3=Springman|first3=S.M.|title=Choosing geotechnical parameters for slope stability assessments in alpine permafrost soils. In 9th international conference on permafrost.|date=2008|publisher=University of Alaska|location=Fairbanks, USA|isbn=978-0-9800179-3-9|pages=1261–1266}}</ref><ref name=Arnaud>{{Cite journal|last=Temme|first=Arnaud J. A. M.|date=2015|title=Using Climber's Guidebooks to Assess Rock Fall Patterns Over Large Spatial and Decadal Temporal Scales: An Example from the Swiss Alps|journal=Geografiska Annaler: Series A, Physical Geography |volume=97|issue=4|pages=793–807|doi=10.1111/geoa.12116|bibcode=2015GeAnA..97..793T |s2cid=55361904}}</ref> Over the past century, an increasing number of alpine rock slope failure events in mountain ranges around the world have been recorded, and some have been attributed to permafrost thaw induced by climate change. The 1987 [[Val Pola landslide]] that killed 22 people in the [[Italian Alps]] is considered one such example.<ref>{{Cite journal|last1=F.|first1=Dramis|last2=M.|first2=Govi|last3=M.|first3=Guglielmin|last4=G.|first4=Mortara|date=1995-01-01|title=Mountain permafrost and slope instability in the Italian Alps: The Val Pola Landslide|journal=Permafrost and Periglacial Processes|volume=6|issue=1|doi=10.1002/ppp.3430060108 |pages=73–81|bibcode=1995PPPr....6...73D }}</ref> In 2002, massive rock and ice falls (up to 11.8&nbsp;million m<sup>3</sup>), earthquakes (up to 3.9 [[Richter scale|Richter]]), floods (up to 7.8&nbsp;million m<sup>3</sup> water), and rapid rock-ice flow to long distances (up to 7.5&nbsp;km at 60&nbsp;m/s) were attributed to slope instability in high mountain permafrost.<ref>{{cite book |doi=10.1130/REG15 |title=Catastrophic Landslides: Effects, Occurrence, and Mechanisms |series=Reviews in Engineering Geology |year=2002 |volume=15 |isbn=0-8137-4115-7 }}</ref>
[[File:Permafrost in Herschel Island 001.jpg|thumb|left|Thawing permafrost in [[Herschel Island]], Canada, 2013.]]
Permafrost thaw can also result in the formation of frozen debris lobes (FDLs), which are defined as "slow-moving landslides composed of soil, rocks, trees, and ice".<ref name="UAF FDLs 2022">{{Cite web| title = FDL: Frozen Debris Lobes | date = 7 January 2022| access-date = 7 January 2022 |series=FDLs |work=[[University of Alaska Fairbanks]]| url = https://fdlalaska.org/}}</ref> This is a notable issue in the [[Alaska]]'s southern [[Brooks Range]], where some FDLs measured over {{convert|100|metre|yards|abbr=on}} in width, {{convert|20|metre|yards|abbr=on}} in height, and {{convert|1000|metre|yards|abbr=on}} in length by 2012.<ref name="Daanen 2012">{{Cite journal | doi = 10.5194/nhess-12-1521-2012 | volume = 12 | pages = 1521–1537 | last1 = Daanen | first1 = Ronald | last2 = Grosse | first2 = Guido | last3 = Darrow | first3 = Margaret | last4 = Hamilton | first4 = T. | last5 = Jones
| first5 = Benjamin | title = Rapid movement of frozen debris-lobes: Implications for permafrost degradation and slope instability in the south-central Brooks Range, Alaska | journal = Natural Hazards and Earth System Sciences
| date = 21 May 2012| issue = 5 | bibcode = 2012NHESS..12.1521D | doi-access = free }}</ref><ref name="Darrow 2016">{{cite journal |last1=Darrow |first1=Margaret M. |last2=Gyswyt |first2=Nora L. |last3=Simpson |first3=Jocelyn M. |last4=Daanen |first4=Ronald P. |last5=Hubbard |first5=Trent D. |title=Frozen debris lobe morphology and movement: an overview of eight dynamic features, southern Brooks Range, Alaska |journal=The Cryosphere |date=12 May 2016 |volume=10 |issue=3 |pages=977–993 |doi=10.5194/tc-10-977-2016 |bibcode=2016TCry...10..977D |doi-access=free }}</ref> As of December 2021, there were 43 frozen debris lobes identified in the southern Brooks Range, where they could potentially threaten both the [[Trans Alaska Pipeline System]] (TAPS) corridor and the [[Dalton Highway]], which is the main transport link between the [[Interior Alaska]] and the [[Alaska North Slope]].<ref name="Hasemyer 2021">{{Cite web | last = Hasemyer| first = David| title = Unleashed by Warming, Underground Debris Fields Threaten to 'Crush' Alaska's Dalton Highway and the Alaska Pipeline | work = Inside Climate News | access-date = 7 January 2022| date = 20 December 2021| url = https://insideclimatenews.org/news/20122021/alaska-frozen-debris-lobes-dalton-highway-pipeline-climate-change/}}</ref>

==== Infrastructure ====
[[File:Hjort 2018 permafrost infrastructure.png|thumb|Map of likely risk to infrastructure from permafrost thaw expected to occur by 2050.<ref name="Hjort2018" />]]
As of 2021, there are 1162 settlements located directly atop the Arctic permafrost, which host an estimated 5 million people. By 2050, permafrost layer below 42% of these settlements is expected to thaw, affecting all their inhabitants (currently 3.3&nbsp;million people).<ref>{{Cite journal |last1=Ramage |first1=Justine |last2=Jungsberg |first2=Leneisja |last3=Wang |first3=Shinan |last4=Westermann |first4=Sebastian |last5=Lantuit |first5=Hugues |last6=Heleniak |first6=Timothy |date=6 January 2021 |title=Population living on permafrost in the Arctic |journal=Population and Environment |volume=43 |issue=1 |pages=22–38 |doi=10.1007/s11111-020-00370-6|bibcode=2021PopEn..43...22R |s2cid=254938760 }}</ref> Consequently, a wide range of infrastructure in permafrost areas is threatened by the thaw.<ref name="Nelson2002">{{Cite journal|last1=Nelson|first1=F. E.|last2=Anisimov|first2=O. A.|last3=Shiklomanov|first3=N. I.|date=2002-07-01|title=Climate Change and Hazard Zonation in the Circum-Arctic Permafrost Regions|journal=Natural Hazards |volume=26|issue=3|pages=203–225|doi=10.1023/A:1015612918401|bibcode=2002NatHa..26..203N |s2cid=35672358 }}</ref><ref>{{Cite book |last1=Barry |first1=Roger Graham |title=The global cryosphere past, present and future |last2=Gan |first2=Thian-Yew |date=2021 |isbn=978-1-108-48755-9 |edition=Second revised |location=Cambridge, United Kingdom |oclc=1256406954 |publisher=Cambridge University Press}}</ref>{{rp|236}} By 2050, it's estimated that nearly 70% of global infrastructure located in the permafrost areas would be at high risk of permafrost thaw, including 30–50% of "critical" infrastructure. The associated costs could reach tens of billions of dollars by the second half of the century.<ref name="Hjort2022">{{Cite journal |last1=Hjort |first1=Jan |last2=Streletskiy |first2=Dmitry |last3=Doré |first3=Guy |last4=Wu |first4=Qingbai |last5=Bjella |first5=Kevin |last6=Luoto |first6=Miska |date=11 January 2022 |title=Impacts of permafrost degradation on infrastructure |journal=Nature Reviews Earth & Environment |volume=3 |issue=1 |pages=24–38 |doi=10.1038/s43017-021-00247-8|bibcode=2022NRvEE...3...24H |hdl=10138/344541 |s2cid=245917456 |url=http://urn.fi/urn:nbn:fi-fe2022101962575 |hdl-access=free }}</ref> Reducing [[greenhouse gas emissions]] in line with the [[Paris Agreement]] is projected to stabilize the risk after mid-century; otherwise, it'll continue to worsen.<ref name="Hjort2018" />

In [[Alaska]] alone, damages to infrastructure by the end of the century would amount to $4.6&nbsp;billion (at 2015 dollar value) if [[Representative Concentration Pathway|RCP8.5]], the high-emission [[climate change scenario]], were realized. Over half stems from the damage to buildings ($2.8&nbsp;billion), but there's also damage to roads ($700&nbsp;million), railroads ($620&nbsp;million), airports ($360&nbsp;million) and [[pipeline transport|pipelines]] ($170&nbsp;million).<ref name="Melvin2016">{{Cite journal |last1=Melvin|first1=April M.|last2=Larsen|first2=Peter|last3=Boehlert|first3=Brent |last4=Neumann|first4=James E.|last5=Chinowsky|first5=Paul|last6=Espinet|first6=Xavier|last7=Martinich|first7=Jeremy|last8=Baumann |first8=Matthew S.|last9=Rennels|first9=Lisa|last10=Bothner|first10=Alexandra|last11=Nicolsky|first11=Dmitry J.|last12=Marchenko |first12=Sergey S. |date=26 December 2016 |title=Climate change damages to Alaska public infrastructure and the economics of proactive adaptation |journal=Proceedings of the National Academy of Sciences |volume=114 |issue=2 |pages=E122–E131 |doi=10.1073/pnas.1611056113 |pmid=28028223 |pmc=5240706 |doi-access=free }}</ref> Similar estimates were done for RCP4.5, a less intense scenario which leads to around {{convert|2.5|C-change|F-change}} by 2100, a level of warming similar to the current projections.<ref name="CAT">{{cite web |url=https://climateactiontracker.org/global/cat-thermometer/ |title=The CAT Thermometer |access-date=25 April 2023}}</ref> In that case, total damages from permafrost thaw are reduced to $3&nbsp;billion, while damages to roads and railroads are lessened by approximately two-thirds (from $700 and $620&nbsp;million to $190 and $220&nbsp;million) and damages to pipelines are reduced more than ten-fold, from $170&nbsp;million to $16&nbsp;million. Unlike the other costs stemming from climate change in Alaska, such as damages from increased [[precipitation]] and flooding, [[climate change adaptation]] is not a viable way to reduce damages from permafrost thaw, as it would cost more than the damage incurred under either scenario.<ref name="Melvin2016" />

In Canada, [[Northwest Territories]] have a population of only 45,000 people in 33 communities, yet permafrost thaw is expected to cost them $1.3&nbsp;billion over 75 years, or around $51&nbsp;million a year. In 2006, the cost of adapting [[Inuvialuit]] homes to permafrost thaw was estimated at $208/m<sup>2</sup> if they were built at pile foundations, and $1,000/m<sup>2</sup> if they didn't. At the time, the average area of a residential building in the territory was around 100&nbsp;m<sup>2</sup>. Thaw-induced damage is also unlikely to be covered by [[home insurance]], and to address this reality, territorial government currently funds Contributing Assistance for Repairs and Enhancements (CARE) and Securing Assistance for Emergencies (SAFE) programs, which provide long- and short-term forgivable loans to help homeowners adapt. It is possible that in the future, mandatory relocation would instead take place as the cheaper option. However, it would effectively tear the local [[Inuit]] away from their ancestral homelands. Right now, their average personal income is only half that of the median NWT resident, meaning that adaptation costs are already disproportionate for them.<ref>{{Cite web|url=https://www.thearcticinstitute.org/reducing-individual-costs-permafrost-thaw-damage-canada-arctic/ |last=Tsui|first=Emily |title=Reducing Individual Costs of Permafrost Thaw Damage in Canada's Arctic |date=March 4, 2021|website=The Arctic Institute}}</ref>

By 2022, up to 80% of buildings in some Northern Russia cities had already experienced damage.<ref name="Hjort2022" /> By 2050, the damage to residential infrastructure may reach $15&nbsp;billion, while total public infrastructure damages could amount to 132&nbsp;billion.<ref>{{cite journal |last1=Melnikov |first1=Vladimir |last2=Osipov |first2=Victor |last3=Brouchkov |first3=Anatoly V. |last4=Falaleeva |first4=Arina A. |last5=Badina |first5=Svetlana V. |last6=Zheleznyak |first6=Mikhail N. |last7=Sadurtdinov |first7=Marat R. |last8=Ostrakov |first8=Nikolay A. |last9=Drozdov |first9=Dmitry S. |last10=Osokin |first10=Alexei B. |last11=Sergeev |first11=Dmitry O. |last12=Dubrovin |first12=Vladimir A. |last13=Fedorov  |first13=Roman Yu. |date=24 January 2022 |title=Climate warming and permafrost thaw in the Russian Arctic: potential economic impacts on public infrastructure by 2050 |journal=Natural Hazards |volume=112 |issue=1 |pages=231–251 |doi=10.1007/s11069-021-05179-6|bibcode=2022NatHa.112..231M |s2cid=246211747 }}</ref> This includes [[oil and gas]] extraction facilities, of which 45% are believed to be at risk.<ref name="Hjort2018">{{Cite journal |last1=Hjort |first1=Jan |last2=Karjalainen |first2=Olli |last3=Aalto |first3=Juha |last4=Westermann |first4=Sebastian |last5=Romanovsky |first5=Vladimir E. |last6=Nelson |first6=Frederick E. |last7=Etzelmüller |first7=Bernd |last8=Luoto |first8=Miska |date=11 December 2018 |title=Degrading permafrost puts Arctic infrastructure at risk by mid-century |journal=Nature Communications |volume=9 |issue=1 |page=5147 |doi=10.1038/s41467-018-07557-4 |pmid=30538247 |pmc=6289964 |bibcode=2018NatCo...9.5147H }}</ref>
[[File:Ran 2022 QTP Permafrost damages 2050.png|thumb|left|Detailed map of Qinghai–Tibet Plateau infrastructure at risk from permafrost thaw under the SSP2-4.5 scenario.<ref name="Ran2022" />]]
Outside of the Arctic, [[Qinghai–Tibet Plateau]] (sometimes known as "the Third Pole"), also has an extensive permafrost area. It is warming at twice the global average rate, and 40% of it is already considered "warm" permafrost, making it particularly unstable. Qinghai–Tibet Plateau has a population of over 10 million people – double the population of permafrost regions in the Arctic – and over 1&nbsp;million m<sup>2</sup> of buildings are located in its permafrost area, as well as 2,631&nbsp;km of [[power line]]s, and 580&nbsp;km of railways.<ref name="Ran2022" /> There are also 9,389&nbsp;km of roads, and around 30% are already sustaining damage from permafrost thaw.<ref name="Hjort2022" /> Estimates suggest that under the scenario most similar to today, [[Shared Socioeconomic Pathways|SSP2-4.5]], around 60% of the current infrastructure would be at high risk by 2090 and simply maintaining it would cost $6.31&nbsp;billion, with adaptation reducing these costs by 20.9% at most. Holding the global warming to {{convert|2|C-change|F-change}} would reduce these costs to $5.65&nbsp;billion, and fulfilling the optimistic [[Paris Agreement]] target of {{convert|1.5|C-change|F-change}} would save a further $1.32&nbsp;billion. In particular, fewer than 20% of railways would be at high risk by 2100 under {{convert|1.5|C-change|F-change}}, yet this increases to 60% at {{convert|2|C-change|F-change}}, while under SSP5-8.5, this level of risk is met by mid-century.<ref name="Ran2022">{{Cite journal |last1=Ran |first1=Youhua |last2=Cheng |first2=Guodong |last3=Dong |first3=Yuanhong |last4=Hjort |first4=Jan |last5=Lovecraft |first5=Amy Lauren |last6=Kang |first6=Shichang |last7=Tan |first7=Meibao |last8=Li |first8=Xin |date=13 October 2022 |title=Permafrost degradation increases risk and large future costs of infrastructure on the Third Pole |journal=Communications Earth & Environment |volume=3 |issue=1 |page=238 |doi=10.1038/s43247-022-00568-6 |bibcode=2022ComEE...3..238R |s2cid=252849121 }}</ref>