Ändra sökning
RefereraExporteraLänk till posten
Permanent länk

Direktlänk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
GIS-based Maps and Area Estimates of Northern Hemisphere Permafrost Extent during the Last Glacial Maximum
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi. Lund University, Sweden.
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi.
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi.
Visa övriga samt affilieringar
Antal upphovsmän: 52016 (Engelska)Ingår i: Permafrost and Periglacial Processes, ISSN 1045-6740, E-ISSN 1099-1530, Vol. 27, nr 1, s. 6-16Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

This study presents GIS-based estimates of permafrost extent in the northern circumpolar region during the Last Glacial Maximum (LGM), based on a review of previously published maps and compilations of field evidence in the form of ice-wedge pseudomorphs and relict sand wedges. We focus on field evidence localities in areas thought to have been located along the past southern border of permafrost. We present different reconstructions of permafrost extent, with areal estimates of exposed sea shelf, ice sheets and glaciers, to assess areas of minimum, likely and maximum permafrost extents. The GIS-based mapping of these empirical reconstructions allows us to estimate the likely area of northern permafrost during the LGM as 34.5 million km(2) (which includes 4.7 million km(2) of permafrost on exposed coastal sea shelves). The minimum estimate is 32.7 million km(2) and the maximum estimate is 35.3 million km(2). The extent of LGM permafrost is estimated to have been between c. 9.1 to 11.7 million km(2) larger than its current extent on land (23.6 million km(2)). However, 2.4 million km(2) of the lost land area currently remains as subsea permafrost on the submerged coastal shelves. The LGM permafrost extent in the northern circumpolar region during the LGM was therefore about 33 percent larger than at present. The net loss of northern permafrost since the LGM is due to its disappearance in large parts of Eurasia, which is not compensated for by gains in North America in areas formerly covered by the Laurentide ice sheet.

Ort, förlag, år, upplaga, sidor
2016. Vol. 27, nr 1, s. 6-16
Nyckelord [en]
LGM, Permafrost, GIS, Area, Paleoenvironment
Nationell ämneskategori
Geovetenskap och miljövetenskap
Forskningsämne
naturgeografi
Identifikatorer
URN: urn:nbn:se:su:diva-129104DOI: 10.1002/ppp.1851ISI: 000371830000002OAI: oai:DiVA.org:su-129104DiVA, id: diva2:921044
Tillgänglig från: 2016-04-19 Skapad: 2016-04-14 Senast uppdaterad: 2022-02-23Bibliografiskt granskad
Ingår i avhandling
1. Northern Permafrost Region Soil Carbon Dynamics since the Last Glacial Maximum: a terrestrial component in the glacial to interglacial carbon cycle
Öppna denna publikation i ny flik eller fönster >>Northern Permafrost Region Soil Carbon Dynamics since the Last Glacial Maximum: a terrestrial component in the glacial to interglacial carbon cycle
2020 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

At the Last Glacial Maximum (LGM), after ~100,000 years of relatively cold temperatures and progressively lower atmospheric carbon dioxide (CO2) concentrations, CO2 levels reached ~180 ppm, which is less than half of what we see today in a much warmer world (~400 ppm). Although much of this increase since the LGM is due to human-induced emissions, about 100 ppm of this increase can be attributed to natural variations seen over glacial to interglacial cycles. The sources for this natural CO2 rise remain unclear despite considerable efforts to constrain its origin. This thesis attempts to describe and quantify the role of soil carbon in this context, with emphasis on the permafrost hypothesis, which states that a shift from glacial to interglacial conditions released permafrost soil carbon to the atmosphere during the deglaciation. We present empirical estimates of the change in the Northern permafrost area between the LGM and present, and the associated soil carbon stock changes. We also partition these soil carbon stock changes at millennial intervals to capture not only the size but the timing of change. We find that the soil carbon stocks north of the Tropics decreased after the LGM to reach a minimum around 10,000 years ago, after which stocks increased to more than compensate for past losses. This may present part of a solution to untangle the marine and atmospheric 13C record, where the marine records suggest that the terrestrial carbon stock has grown since the LGM, while the atmospheric record also indicates terrestrial losses. To estimate the mineral soil carbon stocks, we have relied on vegetation reconstructions. Some of these reconstructions were created with a novel data-driven machine learning approach. This method may facilitate robust vegetation reconstruction when evidence of past conditions is readily available. Results in this thesis highlight the importance of permafrost, loess deposits and peatlands when considering the soil carbon cycle over long time scales.

Ort, förlag, år, upplaga, sidor
Stockholm: Department of Physical Geography, Stockholm University, 2020. s. 50
Serie
Dissertations in Physical Geography, ISSN 2003-2358 ; 6
Nyckelord
Soil organic carbon, Permafrost, Peat, Loess, Vegetation, Biome reconstruction, Last Glacial Maximum, Deglaciation, Glacial-interglacial cycle, Carbon cycle
Nationell ämneskategori
Naturgeografi
Forskningsämne
naturgeografi
Identifikatorer
urn:nbn:se:su:diva-183520 (URN)978-91-7911-234-9 (ISBN)978-91-7911-235-6 (ISBN)
Disputation
2020-09-18, De Geersalen, Geovetenskapens hus, Svante Arrhenius väg 14, digitally via conference (Zoom), public link https://stockholmuniversity.zoom.us/j/62786621027, Stockholm, 13:00 (Engelska)
Opponent
Handledare
Forskningsfinansiär
Vetenskapsrådet, 1359211
Anmärkning

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript.

Tillgänglig från: 2020-08-26 Skapad: 2020-07-20 Senast uppdaterad: 2022-02-26Bibliografiskt granskad

Open Access i DiVA

Fulltext saknas i DiVA

Övriga länkar

Förlagets fulltext

Person

Lindgren, AmelieHugelius, GustafKuhry, Peter

Sök vidare i DiVA

Av författaren/redaktören
Lindgren, AmelieHugelius, GustafKuhry, Peter
Av organisationen
Institutionen för naturgeografi
I samma tidskrift
Permafrost and Periglacial Processes
Geovetenskap och miljövetenskap

Sök vidare utanför DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetricpoäng

doi
urn-nbn
Totalt: 125 träffar
RefereraExporteraLänk till posten
Permanent länk

Direktlänk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf