The middle Pleistocene transition: characteristics, mechanisms, and implications for long-term changes in atmospheric pCO2

Clark, Peter U.; Archer, David; Pollard, David; Blum, Joel D.; Rial, J. A.; Brovkin, Victor; Mix, Alan C; Pisias, Nicklas G; Roy, Martin

doi:10.1016/j.quascirev.2006.07.008

Cited by 914 publications

(839 citation statements)

References 121 publications

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“…8) is similar to that simulated in the BE and CC200 experiments. This is consistent with paleoclimate evidence of a similar southward extent of the Laurentide ice sheet in the 40-and 100-kyr worlds reviewed by Clark et al (2006). The large difference in volume for ice sheets with a similar area is explained by the fact that in the REG experiments, due to strong sliding over a broader sediment-covered area, the maximum thickness of the central part of the Laurentide ice sheet is much smaller than at the end of the long glacial cycles simulated in BE or CC200 experiments.…”

Section: The Role Of Regolithsupporting

confidence: 90%

The role of orbital forcing, carbon dioxide and regolith in 100 kyr glacial cycles

2011

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Abstract. The origin of the 100 kyr cyclicity, which dominates ice volume variations and other climate records over the past million years, remains debatable. Here, using a comprehensive Earth system model of intermediate complexity, we demonstrate that both strong 100 kyr periodicity in the ice volume variations and the timing of glacial terminations during past 800 kyr can be successfully simulated as direct, strongly nonlinear responses of the climate-cryosphere system to orbital forcing alone, if the atmospheric CO 2 concentration stays below its typical interglacial value. The existence of long glacial cycles is primarily attributed to the North American ice sheet and requires the presence of a large continental area with exposed rocks. We show that the sharp, 100 kyr peak in the power spectrum of ice volume results from the long glacial cycles being synchronized with the Earth's orbital eccentricity. Although 100 kyr cyclicity can be simulated with a constant CO 2 concentration, temporal variability in the CO 2 concentration plays an important role in the amplification of the 100 kyr cycles.

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Section: The Role Of Regolithsupporting

confidence: 90%

The role of orbital forcing, carbon dioxide and regolith in 100 kyr glacial cycles

2011

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“…However, reconstructed deep-water temperatures for the MPT are scarce [Dwyer et al, 1995;Lear et al, 2000], as are reconstructed pCO 2 values [Pearson and Palmer, 2000]. Using the deep-water data of Dwyer et al [1995], in combination to the LR04 benthic d 18 O stack [Lisiecki and Raymo, 2005], Clark et al [2006] have calculated that the increasing benthic d 18 O values across the MPT reflected a 50% ice volume increase but also a 1.4°C fall in deep-water temperatures. It is clear that to fully evaluate this hypothesis, high-resolution reconstructions of deep-water temperatures are required that span the MPT.…”

Section: Implications For the Mptmentioning

confidence: 99%

Expansion of subarctic water masses in the North Atlantic and Pacific oceans and implications for mid‐Pleistocene ice sheet growth

et al. 2008

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[1] Past surface ocean circulation changes associated with the mid-Pleistocene transition, 0.9-0.6 Ma, were reconstructed in the northern North Atlantic (ODP 983) and the northwest Pacific (ODP 882), using proxies for subarctic/subpolar water mass distributions (%C 37:4 alkenone) and sea surface temperature (U 37 K ). Both sites experienced a secular expansion of subarctic waters from $1.15 Ma, spanning both glacial and interglacial intervals. After 0.9 Ma, low %C 37:4 at Site 983 records a northward retreat of subarctic waters during interglacials in the Atlantic, while continued high glacial %C 37:4 indicate extensive subarctic waters during glacial maxima associated with the development of the larger late Pleistocene ice sheets. In contrast, a secular decline in %C 37:4 occurred at Site 882 from 0.9 to 0.5 Ma, marking a more gradual retreat of subarctic conditions in the Pacific. It is proposed that the expansion of subarctic waters between 1.15 and 0.9 Ma exerted negative feedbacks to the moisture supply to the ice sheet source regions and may account for the apparent delayed ice sheet response to atmosphere-ocean circulation changes associated with the mid-Pleistocene transition that began as early as 1.2 Ma.

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“…First, temporal changes in the radiative balance of climate are important because ice masses have high albedo and reflect incoming solar radiation (e.g., Hansen et al, 2007Hansen et al, , 2008K€ ohler et al, 2010, 2015Rohling et al, 2012;PALAEOSENS project members, 2012;Martínez-Botí et al, 2015;Friedrich et al, 2016). Second, temporal development of ice-age cycles provides critical information about the nature of long-term climate cooling over the past few million years, in response to CO 2 reduction and interactions among ice, land cover, and climate (e.g., Clark et al, 2006;K€ ohler and Bintanja, 2008;de Boer et al, 2010de Boer et al, , 2012Hansen et al, 2013). Third, variable amplitude of individual ice ages helps to determine the relationship between climate change, astronomical climate forcing cycles, and climate feedbacks on timescales of 10se100s of kiloyears (e.g., Oglesby, 1990;Imbrie et al, 1993;Raymo et al, 2006;Colleoni et al, 2011Colleoni et al, , 2016Ganopolski and Calov, 2011;Carlson and Winsor, 2012;Abe-Ouchi et al, 2013;Hatfield et al, 2016;Liakka et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Differences between the last two glacial maxima and implications for ice-sheet, δ18O, and sea-level reconstructions

Rohling

Hibbert

Williams

et al. 2017

Quaternary Science Reviews

115

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Arctic ice shelf Last Interglacial Glacioisostatic adjustment a b s t r a c t Studies of past glacial cycles yield critical information about climate and sea-level (ice-volume) variability, including the sensitivity of climate to radiative change, and impacts of crustal rebound on sealevel reconstructions for past interglacials. Here we identify significant differences between the last and penultimate glacial maxima (LGM and PGM) in terms of global volume and distribution of land ice, despite similar temperatures and radiative forcing. Our analysis challenges conventional views of relationships between global ice volume, sea level, seawater oxygen isotope values, and deep-sea temperature, and supports the potential presence of large floating Arctic ice shelves during the PGM. The existence of different glacial 'modes' calls for focussed research on the complex processes behind ice-age development. We present a glacioisostatic assessment to demonstrate how a different PGM ice-sheet configuration might affect sea-level estimates for the last interglacial. Results suggest that this may alter existing last interglacial sea-level estimates, which often use an LGM-like ice configuration, by several metres (likely upward).

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The middle Pleistocene transition: characteristics, mechanisms, and implications for long-term changes in atmospheric pCO2

Cited by 914 publications

References 121 publications

The role of orbital forcing, carbon dioxide and regolith in 100 kyr glacial cycles

The role of orbital forcing, carbon dioxide and regolith in 100 kyr glacial cycles

Expansion of subarctic water masses in the North Atlantic and Pacific oceans and implications for mid‐Pleistocene ice sheet growth

Differences between the last two glacial maxima and implications for ice-sheet, δ18O, and sea-level reconstructions

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