8.2千年事件

8.2千年事件是發生在8,200年之前，或者說公元前6,200年的全球氣溫突然下降。持續了2-4個世紀。比之前的新仙女木期的降溫要溫和，但是比之後的小冰河期降溫要猛烈得多。8.2千年事件是全新世氣候最佳期的一個意外。在這一事件中，大氣中的甲烷下降了80 ppb或者說15%^[1]。

1960年，瑞士植物學家Heinrich Zoller（德語：Heinrich Zoller）首先辨識出這一氣候事件，稱之為Misox oscillation^[2]。在挪威稱之為Finse event^[3]。 Bond等人認為8.2千年事件與1,500年氣候周期有關，稱之為「Bond event 5」^[4]。

最強的證據出自北大西洋地區；氣候的突然轉折清楚地記錄在格陵蘭的冰芯與北大西洋的沉積物中^[5]^[6]^[7]。在南極洲與南美的指示不明顯^[8]^[9]。這是全球性的變化，海平面變化尤為顯著。

8.2千年事件可能是北美的勞倫臺德冰蓋（英語：Laurentide ice sheet）最後的融水所造成，最可能是冰蓋融水湖——Ojibway冰融湖與Agassiz冰融湖突然崩潰注入了北大西洋^[10]^[11]^[12]（同類事件造成了Missoula洪水，產生了Channeled scablands與哥倫比亞河盆地）。冰融水的衝擊影響了北大西洋的溫鹽環流，降低了向北的熱量輸送，造成北大西洋降溫。降溫幅度為1-5 °C。在格陵蘭，這一事件開始於西元前6225±30年，20年內降溫3.3 °C，最冷時段持續了60年，總持續150年^[1]。印度尼西亞的古珊瑚礁鑽探取樣表明，熱帶地區降溫了3 °C^[13]。這一事件也導致了全球CO₂在三百年時間裏下降25ppm^[14]。

北非變得更為乾旱。東非經歷了5個世紀的大旱。在西亞，特別是美索不達米亞，造成了300年的乾旱寒冷，迫使當地人發展了灌溉農業、城市與階級的出現。但是這些多世紀跨度的變化難以與格陵蘭100多年的冰芯數據直接關聯起來。

最初的冰融水衝擊造成了海平面上升了0.5-4米。根據對冰蓋與冰融湖的體積的估計，造成了0.4-1.2米的海平面上升。根據現代河流三角洲之下沉積物的分析，8.2千年事件造成了冰後海平面正常上升之外的額外的2-4米升高^[15]。

[1]
Kobashi, T.; et al.. Precise timing and characterization of abrupt climate change 8200 years ago from air trapped in polar ice. Quaternary Science Reviews. 2007, 26: 1212–1222. Bibcode:2007QSRv...26.1212K. doi:10.1016/j.quascirev.2007.01.009.
[2]
Zoller, Heinrich. Pollenanalytische Untersuchungen zur Vegetationsgeschichte der insubrischen Schweiz. Denkschriften der Schweizerischen Naturforschenden Gesellschaft. 1960, 83: 45–156. ISSN 0366-970X （德語）.
[3]
Nesje, Atle; Dahl, Svein Olaf. The Greenland 8200 cal. yr BP event detected in loss-on-ignition profiles in Norwegian lacustrine sediment sequences. Journal of Quaternary Science. 2001, 16 (2): 155–166. Bibcode:2001JQS....16..155N. doi:10.1002/jqs.567.
[4]
Bond, G.; et al.. A Pervasive Millennial-Scale Cycle in North Atlantic Holocene and Glacial Climates (PDF). Science. 1997, 278 (5341): 1257–66 [2012-09-21]. Bibcode:1997Sci...278.1257B. doi:10.1126/science.278.5341.1257. （原始內容 (PDF)存檔於2008-02-27）.
[5]
Alley, R. B.; et al.. Holocene climatic instability; a prominent, widespread event 8,200 yr ago. Geology. 1997, 25 (6): 483–6 [2012-09-21]. Bibcode:1997Geo....25..483A. doi:10.1130/0091-7613(1997)025<0483:HCIAPW>2.3.CO;2. （原始內容存檔於2011-09-28）.
[6]
Alley, Richard B.; Ágústsdóttir, Anna Maria. The 8k event: cause and consequences of a major Holocene abrupt climate change. Quaternary Science Reviews. 2005, 24 (10-11): 1123–49. Bibcode:2005QSRv...24.1123A. doi:10.1016/j.quascirev.2004.12.004.
[7]
Sarmaja-Korjonen, Kaarina; Seppa, H. Abrupt and consistent responses of aquatic and terrestrial ecosystems to the 8200 cal. yr cold event: a lacustrine record from Lake Arapisto, Finland. The Holocene. 2007, 17 (4): 457–467. doi:10.1177/0959683607077020.
[8]
Burroughs, William J. [ed.]. Climate: Into the 21st Century. Cambridge: Cambridge University Press. 2003. ISBN 0-521-79202-9.
[9]
Ljung, K.; et al.. South Atlantic island record reveals a South Atlantic response to the 8.2kyr event. Climate of the Past. 2007, 4 (1): 35–45 [2012-09-21]. doi:10.5194/cp-4-35-2008. （原始內容存檔於2012-02-10）.
[10]
Ehlers, Jürgen; Gibbard, Philip L. Quaternary Glaciations – Extent and Chronology. Part II: North America. Amsterdam: Elsevier. 2004: 257–262. ISBN 0-444-51592-5.
[11]
Barber, D. C.; et al.. Forcing of the cold event 8,200 years ago by catastrophic drainage of Laurentide Lakes. Nature. 1999, 400 (6742): 344–8. Bibcode:1999Natur.400..344B. doi:10.1038/22504.
[12]
Ellison, Christopher R. W.; Chapman, Mark R.; Hall, Ian R. Surface and Deep Ocean Interactions During the Cold Climate Event 8200 Years Ago. Science. 2006, 312 (5782): 1929–32. Bibcode:2006Sci...312.1929E. PMID 16809535. doi:10.1126/science.1127213.
[13]
Fagan, Brian. The Long Summer: How Climate Changed Civilization. New York: Basic Books. 2004: 107–108. ISBN 0-465-02281-2.
[14]
Wagner, Friederike; et al.. Rapid atmospheric CO₂ changes associated with the 8,200-years-B.P. cooling event. Proc. Natl. Acad. Sci. U.S.A. 2002, 99 (19): 12011–4. Bibcode:2002PNAS...9912011W. PMC 129389 . PMID 12202744. doi:10.1073/pnas.182420699.
[15]
Hijma, Marc P.; Cohen, Kim M. Timing and magnitude of the sea-level jump preluding the 8.2 kiloyear event. Geology. March 2010, 38 (3): 275–8 [2012-09-21]. doi:10.1130/G30439.1. （原始內容存檔於2011-05-05）.

[Kobashi-1] [1]
Kobashi, T.; et al.. Precise timing and characterization of abrupt climate change 8200 years ago from air trapped in polar ice. Quaternary Science Reviews. 2007, 26: 1212–1222. Bibcode:2007QSRv...26.1212K. doi:10.1016/j.quascirev.2007.01.009.

[Zoller1960-2] [2]
Zoller, Heinrich. Pollenanalytische Untersuchungen zur Vegetationsgeschichte der insubrischen Schweiz. Denkschriften der Schweizerischen Naturforschenden Gesellschaft. 1960, 83: 45–156. ISSN 0366-970X （德語）.

[Nesje2001-3] [3]
Nesje, Atle; Dahl, Svein Olaf. The Greenland 8200 cal. yr BP event detected in loss-on-ignition profiles in Norwegian lacustrine sediment sequences. Journal of Quaternary Science. 2001, 16 (2): 155–166. Bibcode:2001JQS....16..155N. doi:10.1002/jqs.567.

[Bond1997-4] [4]
Bond, G.; et al.. A Pervasive Millennial-Scale Cycle in North Atlantic Holocene and Glacial Climates (PDF). Science. 1997, 278 (5341): 1257–66 [2012-09-21]. Bibcode:1997Sci...278.1257B. doi:10.1126/science.278.5341.1257. （原始內容 (PDF)存檔於2008-02-27）.

[5] [5]
Alley, R. B.; et al.. Holocene climatic instability; a prominent, widespread event 8,200 yr ago. Geology. 1997, 25 (6): 483–6 [2012-09-21]. Bibcode:1997Geo....25..483A. doi:10.1130/0091-7613(1997)025<0483:HCIAPW>2.3.CO;2. （原始內容存檔於2011-09-28）.

[6] [6]
Alley, Richard B.; Ágústsdóttir, Anna Maria. The 8k event: cause and consequences of a major Holocene abrupt climate change. Quaternary Science Reviews. 2005, 24 (10-11): 1123–49. Bibcode:2005QSRv...24.1123A. doi:10.1016/j.quascirev.2004.12.004.

[7] [7]
Sarmaja-Korjonen, Kaarina; Seppa, H. Abrupt and consistent responses of aquatic and terrestrial ecosystems to the 8200 cal. yr cold event: a lacustrine record from Lake Arapisto, Finland. The Holocene. 2007, 17 (4): 457–467. doi:10.1177/0959683607077020.

[8] [8]
Burroughs, William J. [ed.]. Climate: Into the 21st Century. Cambridge: Cambridge University Press. 2003. ISBN 0-521-79202-9.

[9] [9]
Ljung, K.; et al.. South Atlantic island record reveals a South Atlantic response to the 8.2kyr event. Climate of the Past. 2007, 4 (1): 35–45 [2012-09-21]. doi:10.5194/cp-4-35-2008. （原始內容存檔於2012-02-10）.

[10] [10]
Ehlers, Jürgen; Gibbard, Philip L. Quaternary Glaciations – Extent and Chronology. Part II: North America. Amsterdam: Elsevier. 2004: 257–262. ISBN 0-444-51592-5.

[11] [11]
Barber, D. C.; et al.. Forcing of the cold event 8,200 years ago by catastrophic drainage of Laurentide Lakes. Nature. 1999, 400 (6742): 344–8. Bibcode:1999Natur.400..344B. doi:10.1038/22504.

[12] [12]
Ellison, Christopher R. W.; Chapman, Mark R.; Hall, Ian R. Surface and Deep Ocean Interactions During the Cold Climate Event 8200 Years Ago. Science. 2006, 312 (5782): 1929–32. Bibcode:2006Sci...312.1929E. PMID 16809535. doi:10.1126/science.1127213.

[13] [13]
Fagan, Brian. The Long Summer: How Climate Changed Civilization. New York: Basic Books. 2004: 107–108. ISBN 0-465-02281-2.

[14] [14]
Wagner, Friederike; et al.. Rapid atmospheric CO₂ changes associated with the 8,200-years-B.P. cooling event. Proc. Natl. Acad. Sci. U.S.A. 2002, 99 (19): 12011–4. Bibcode:2002PNAS...9912011W. PMC 129389 . PMID 12202744. doi:10.1073/pnas.182420699.

[Hijma2010-15] [15]
Hijma, Marc P.; Cohen, Kim M. Timing and magnitude of the sea-level jump preluding the 8.2 kiloyear event. Geology. March 2010, 38 (3): 275–8 [2012-09-21]. doi:10.1130/G30439.1. （原始內容存檔於2011-05-05）.

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8.2千年事件

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