DOI: 10.1016/j.quascirev.2015.04.015
Scopus记录号: 2-s2.0-84928898826
论文题名: The role of CO<inf>2</inf> decline for the onset of Northern Hemisphere glaciation
作者: Willeit M. ; Ganopolski A. ; Calov R. ; Robinson A. ; Maslin M.
刊名: Quaternary Science Reviews
ISSN: 2773791
出版年: 2015
卷: 119 起始页码: 22
结束页码: 34
语种: 英语
英文关键词: Carbon dioxide
; Earth system modelling
; Ice sheets
; Northern hemishpere glaciation
; Paleoclimatology
; Pliocene-Pleistocene transition
Scopus关键词: Atmospheric temperature
; Carbon dioxide
; Glacial geology
; Glaciers
; Incident solar radiation
; Inverse problems
; Oceanography
; Orbits
; Repair
; Sea level
; Solar radiation
; Surface waters
; Earth systems
; Ice sheet
; Northern hemishpere glaciation
; Paleoclimatology
; Pleistocene
; Ice
; benthos
; carbon dioxide
; climate change
; concentration (composition)
; cyclicity
; glaciation
; ice sheet
; insolation
; Northern Hemisphere
; orbital forcing
; paleoclimate
; Pliocene-Pleistocene boundary
; reconstruction
; sea level change
; sea surface temperature
; Arctic
; Eurasia
; Greenland
; North America
英文摘要: The Pliocene-Pleistocene Transition (PPT), from around 3.2 to 2.5 million years ago (Ma), represented a major shift in the climate system and was characterized by a gradual cooling trend and the appearance of large continental ice sheets over northern Eurasia and North America. Paleo evidence indicates that the PPT was accompanied and possibly caused by a decrease in atmospheric CO2 , but the temporal resolution of CO2 reconstructions is low for this period of time and uncertainties remain large. Therefore, instead of applying existent CO2 reconstructions we solved an 'inverse' problem by finding a schematic CO2 concentration scenario that allows us to simulate the temporal evolution of key climate characteristics in agreement with paleoclimate records. To this end, we performed an ensemble of transient simulations with an Earth system model of intermediate complexity from which we derived a best guess transient CO2 scenario for the interval from 3.2 to 2.4Ma that gives the best fit between the simulated and reconstructed benthic δ18O and global sea surface temperature evolution. Our data-constrained CO2 scenarios are consistent with recent CO2 reconstructions and suggest a gradual CO2 decline from 375-425 to 275-300ppm, between 3.2 and 2.4Ma. In addition to a gradual decline, the best fit to paleoclimate data requires the existence of pronounced CO2 variability coherent with the 41-kyr (1 kyr = 1000 years) obliquity cycle. In our simulations the long-term CO2 decline is accompanied by a relatively abrupt intensification of Northern Hemisphere glaciation at around 2.7Ma. This is the result of a threshold behaviour of the ice sheets response to gradual CO2 decrease and orbital forcing. The simulated Northern Hemisphere ice sheets during the early Pleistocene glacial cycles reach a maximum volume equivalent to a sea level drop of about 40m. Both ice volume and benthic δ18O are dominated by 41-kyr cyclicity. Our simulations suggest that before 2.7Ma Greenland was ice free during summer insolation maxima and only partly ice covered during periods of minimum summer insolation. A fully glaciated Greenland comparable to its present-day ice volume is modelled only during glacial maxima after 2.7Ma and more continuously after 2.5Ma. © 2015. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/59924
Appears in Collections: 过去全球变化的重建
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作者单位: Potsdam Institute for Climate Impact Research, Potsdam, Germany; Complutense University of Madrid, Madrid, Spain; Geosciences Institute, UCM-CSIC, Madrid, Spain; Department of Geography, University College London, London, United Kingdom
Recommended Citation:
Willeit M.,Ganopolski A.,Calov R.,et al. The role of CO<inf>2</inf> decline for the onset of Northern Hemisphere glaciation[J]. Quaternary Science Reviews,2015-01-01,119