8.2千年事件

8.2千年事件是发生在8,200年之前，或者说公元前6,200年的全球气温突然下降。持续了2-4个世纪。比之前的新仙女木期的降温要温和，但是比之后的小冰河期降温要猛烈得多。8.2千年事件是全新世气候最佳期的一个意外。在这一事件中，大气中的甲烷下降了80 ppb或者说15%^[1]。

1960年，瑞士植物学家Heinrich Zoller（德语：Heinrich Zoller）首先辨识出这一气候事件，称之为Misox oscillation^[2]。在挪威称之为Finse event^[3]。 Bond等人认为8.2千年事件与1,500年气候周期有关，称之为“Bond event 5”^[4]。

最强的证据出自北大西洋地区；气候的突然转折清楚地记录在格陵兰的冰芯与北大西洋的沉积物中^[5]^[6]^[7]。在南极洲与南美的指示不明显^[8]^[9]。这是全球性的变化，海平面变化尤为显著。

8.2千年事件可能是北美的劳伦台德冰盖（英语：Laurentide ice sheet）最后的融水所造成，最可能是冰盖融水湖——Ojibway冰融湖与Agassiz冰融湖突然崩溃注入了北大西洋^[10]^[11]^[12]（同类事件造成了Missoula洪水，产生了Channeled scablands与哥伦比亚河盆地）。冰融水的冲击影响了北大西洋的温盐环流，降低了向北的热量输送，造成北大西洋降温。降温幅度为1-5 °C。在格陵兰，这一事件开始于公元前6225±30年，20年内降温3.3 °C，最冷时段持续了60年，总持续150年^[1]。印度尼西亚的古珊瑚礁钻探取样表明，热带地区降温了3 °C^[13]。这一事件也导致了全球CO₂在三百年时间里下降25ppm^[14]。

北非变得更为干旱。东非经历了5个世纪的大旱。在西亚，特别是美索不达米亚，造成了300年的干旱寒冷，迫使当地人发展了灌溉农业、城市与阶级的出现。但是这些多世纪跨度的变化难以与格陵兰100多年的冰芯数据直接关联起来。

最初的冰融水冲击造成了海平面上升了0.5-4米。根据对冰盖与冰融湖的体积的估计，造成了0.4-1.2米的海平面上升。根据现代河流三角洲之下沉积物的分析，8.2千年事件造成了冰后海平面正常上升之外的额外的2-4米升高^[15]。

参见

参考文献

[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 （德语）.
[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. （原始内容 (PDF)存档于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. （原始内容存档于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. （原始内容存档于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. （原始内容存档于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 （德语）.

[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. （原始内容 (PDF)存档于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. （原始内容存档于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. （原始内容存档于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. （原始内容存档于2011-05-05）.

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