European Climatic Response to Millennial-Scale Changes in the Atmosphere–Ocean System during the Last Glacial Period

Pollen, foraminifer, dinocyst, and coarse lithic high-resolution analyses and δ18O measurements have been carried out for the last-glacial section of marine core MD95-2042 located near the southwestern margin of the Iberian Peninsula. The pollen data indicate a high frequency of vegetational changes on the adjacent continent during this period, suggesting a climatic variability very similar to that of the Dansgaard-Oeschger cycles recorded by the Greenland ice cores. The detailed direct correlation of the terrestrial and marine proxy data from core MD95-2042 indicates a three-phase pattern of Heinrich events in land and ocean environments. The first and last phases of the H5 and H4 events are characterized by a mild and humid climate in southwestern Europe, probably associated with the European origin of the ice-rafted detritus. The middle phase exhibits a cold and dry climate in Iberia linked with the maximum input of ice-rafted detritus. This phase seems to correspond with the Laurentide ice-sheet surges. Between the Heinrich events, several cold and dry periods on land are correlated with stades of the Dansgaard-Oeschger cycles. The impact of the Dansgaard-Oeschger stades in southwestern Europe seems to be preferentially connected to the cold winter air masses reaching this mid-latitude region.

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An ocean–ice coupled response during the last glacial: a view from a marine isotopic stage 3 record south of the Faeroe Shetland Gateway

Climate of the Past ◽

10.5194/cp-8-1997-2012 ◽

2012 ◽

Vol 8 (6) ◽

pp. 1997-2017 ◽

Cited By ~ 12

Author(s):

J. Zumaque ◽

F. Eynaud ◽

S. Zaragosi ◽

F. Marret ◽

K. M. Matsuzaki ◽

...

Keyword(s):

Climatic Variability ◽

Ice Sheets ◽

Ice Sheet ◽

Ice Cores ◽

Stable Isotope Ratio ◽

Sea Surface ◽

Marine Isotopic Stage ◽

Last Glacial ◽

Fluorescence Measurements ◽

The Last Glacial

Abstract. The rapid climatic variability characterising the Marine Isotopic Stage (MIS) 3 (~60–30 cal ka BP) provides key issues to understand the atmosphere–ocean–cryosphere dynamics. Here we investigate the response of sea-surface paleoenvironments to the MIS3 climatic variability through the study of a high resolution oceanic sedimentological archive (core MD99-2281, 60°21' N; 09°27' W; 1197 m water depth), retrieved during the MD114-IMAGES (International Marine Global Change Study) cruise from the southern part of the Faeroe Bank. This sector was under the proximal influence of European ice sheets (Fennoscandian Ice Sheet to the East, British Irish Ice Sheet to the South) during the last glacial and thus probably responded to the MIS3 pulsed climatic changes. We conducted a multi-proxy analysis of core MD99-2281, including magnetic properties, x-ray fluorescence measurements, characterisation of the coarse (>150 μm) lithic fraction (grain concentration) and the analysis of selected biogenic proxies (assemblages and stable isotope ratio of calcareous planktonic foraminifera, dinoflagellate cyst – e.g. dinocyst – assemblages). Results presented here are focussed on the dinocyst response, this proxy providing the reconstruction of past sea-surface hydrological conditions, qualitatively as well as quantitatively (e.g. transfer function sensu lato). Our study documents a very coherent and sensitive oceanic response to the MIS3 rapid climatic variability: strong fluctuations, matching those of stadial/interstadial climatic oscillations as depicted by Greenland ice cores, are recorded in the MD99-2281 archive. Proxies of terrigeneous and detritical material suggest increases in continental advection during Greenland Stadials (including Heinrich events), the latter corresponding also to southward migrations of polar waters. At the opposite, milder sea-surface conditions seem to develop during Greenland Interstadials. After 30 ka, reconstructed paleohydrological conditions evidence strong shifts in SST: this increasing variability seems consistent with the hypothesised coalescence of the British and Fennoscandian ice sheets at that time, which could have directly influenced sea-surface environments in the vicinity of core MD99-2281.

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Millennial and sub-millennial scale climatic variations recorded in polar ice cores over the last glacial period

Climate of the Past Discussions ◽

10.5194/cpd-6-135-2010 ◽

2010 ◽

Vol 6 (1) ◽

pp. 135-183 ◽

Cited By ~ 6

Author(s):

E. Capron ◽

A. Landais ◽

J. Chappellaz ◽

A. Schilt ◽

D. Buiron ◽

...

Keyword(s):

Climatic Variability ◽

Ice Sheets ◽

Ice Cores ◽

Glacial Period ◽

Last Glacial Period ◽

Last Glacial ◽

Dronning Maud Land ◽

Mis 5 ◽

The Last Glacial ◽

Millennial Scale

Abstract. Since its discovery in Greenland ice cores, the millennial scale climatic variability of the last glacial period has been increasingly documented at all latitudes with studies focusing mainly on Marine Isotopic Stage 3 (MIS 3; 28–60 thousand of years before present, hereafter ka) and characterized by short Dansgaard-Oeschger (DO) events. Recent and new results obtained on the EPICA and NorthGRIP ice cores now precisely describe the rapid variations of Antarctic and Greenland temperature during MIS 5 (73.5–123 ka), a time period corresponding to relatively high sea level. The results display a succession of long DO events enabling us to highlight a sub-millennial scale climatic variability depicted by i) short-lived and abrupt warming events preceding some Greenland InterStadial (GIS) (precursor-type events) and ii) abrupt warming events at the end of some GIS (rebound-type events). The occurrence of these secondary events is suggested to be driven by the Northern Hemisphere summertime insolation at 65° N together with the internal forcing of ice sheets. Thanks to a recent NorthGRIP-EPICA Dronning Maud Land (EDML) common timescale over MIS 5, the bipolar sequence of climatic events can be established at millennial to sub-millennial timescale. This provides evidence that a linear relationship is not satisfactory in explaining the link between Antarctic warming amplitudes and the duration of their concurrent Greenland Stadial (GS) for the entire glacial period. The conceptual model for a thermal bipolar seesaw permits a reconstruction of the Antarctic response to the northern millennial and sub-millennial scale variability over MIS 5. However, we show that when ice sheets are extensive, Antarctica does not necessarily warm during the whole GS as the thermal bipolar seesaw model would predict.

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Millennial and sub-millennial scale climatic variations recorded in polar ice cores over the last glacial period

Climate of the Past ◽

10.5194/cp-6-345-2010 ◽

2010 ◽

Vol 6 (3) ◽

pp. 345-365 ◽

Cited By ~ 113

Author(s):

E. Capron ◽

A. Landais ◽

J. Chappellaz ◽

A. Schilt ◽

D. Buiron ◽

...

Keyword(s):

Climatic Variability ◽

Ice Core ◽

Ice Sheets ◽

Ice Cores ◽

Glacial Period ◽

Last Glacial Period ◽

Last Glacial ◽

Mis 5 ◽

The Last Glacial ◽

Millennial Scale

Abstract. Since its discovery in Greenland ice cores, the millennial scale climatic variability of the last glacial period has been increasingly documented at all latitudes with studies focusing mainly on Marine Isotopic Stage 3 (MIS 3; 28–60 thousand of years before present, hereafter ka) and characterized by short Dansgaard-Oeschger (DO) events. Recent and new results obtained on the EPICA and NorthGRIP ice cores now precisely describe the rapid variations of Antarctic and Greenland temperature during MIS 5 (73.5–123 ka), a time period corresponding to relatively high sea level. The results display a succession of abrupt events associated with long Greenland InterStadial phases (GIS) enabling us to highlight a sub-millennial scale climatic variability depicted by (i) short-lived and abrupt warming events preceding some GIS (precursor-type events) and (ii) abrupt warming events at the end of some GIS (rebound-type events). The occurrence of these sub-millennial scale events is suggested to be driven by the insolation at high northern latitudes together with the internal forcing of ice sheets. Thanks to a recent NorthGRIP-EPICA Dronning Maud Land (EDML) common timescale over MIS 5, the bipolar sequence of climatic events can be established at millennial to sub-millennial timescale. This shows that for extraordinary long stadial durations the accompanying Antarctic warming amplitude cannot be described by a simple linear relationship between the two as expected from the bipolar seesaw concept. We also show that when ice sheets are extensive, Antarctica does not necessarily warm during the whole GS as the thermal bipolar seesaw model would predict, questioning the Greenland ice core temperature records as a proxy for AMOC changes throughout the glacial period.

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Last glacial fire regime variability in western France inferred from microcharcoal preserved in core MD04-2845, Bay of Biscay

Quaternary Research ◽

10.1016/j.yqres.2009.01.007 ◽

2009 ◽

Vol 71 (3) ◽

pp. 385-396 ◽

Cited By ~ 25

Author(s):

Anne-Laure Daniau ◽

Maria Fernanda Sánchez Goñi ◽

Josette Duprat

Keyword(s):

Western Europe ◽

Fire Regime ◽

Climatic Variability ◽

Bay Of Biscay ◽

Glacial Period ◽

Last Glacial Period ◽

Last Glacial ◽

Heinrich Events ◽

Neogloboquadrina Pachyderma ◽

The Last Glacial

AbstractHigh resolution multiproxy analysis (microcharcoal, pollen, organic carbon, Neogloboquadrina pachyderma (s), ice rafted debris) of the deep-sea record MD04-2845 (Bay of Biscay) provides new insights for understanding mechanisms of fire regime variability of the last glacial period in western France. Fire regime of western France closely follows Dansgaard–Oeschger climatic variability and presents the same pattern than that of southwestern Iberia, namely low fire regime associated with open vegetation during stadials including Heinrich events, and high fire regime associated with open forest during interstadials. This supports a regional climatic control on fire regime for western Europe through fuel availability for the last glacial period. Additionally, each of Heinrich events 6, 5 and 4 is characterised by three episodes of fire regime, with a high regime bracketed by lower fire regime episodes, related to vegetational succession and complex environmental condition changes.

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Influence of ablation-related processes in the built-up of simulated Northern Hemisphere ice sheets during the last glacial cycle

The Cryosphere Discussions ◽

10.5194/tcd-6-4897-2012 ◽

2012 ◽

Vol 6 (6) ◽

pp. 4897-4938 ◽

Cited By ~ 1

Author(s):

S. Charbit ◽

C. Dumas ◽

M. Kageyama ◽

D. M. Roche ◽

C. Ritz

Keyword(s):

Northern Hemisphere ◽

Ice Sheets ◽

Ice Sheet ◽

Glacial Cycle ◽

Satisfactory Description ◽

Last Glacial ◽

Transient Simulations ◽

Main Driver ◽

The Impact ◽

The Last Glacial

Abstract. Since the original formulation of the positive-degree-day (PDD) method, different PDD calibrations have been proposed in the literature in response to the increasing number of observations. Although these formulations provide a satisfactory description of the present-day Greenland geometry, they have not all been tested for paleo ice sheets. Using the climate-ice sheet model CLIMBER-GRISLI coupled with different PDD models, we evaluate how the parameterization of the ablation may affect the evolution of Northern Hemisphere ice sheets in the transient simulations of the last glacial cycle. Results from fully coupled simulations are compared to time-slice experiments carried out at different key periods of the last glacial period. We find large differences in the simulated ice sheets according to the chosen PDD model. These differences occur as soon as the onset of glaciation, therefore affecting the subsequent evolution of the ice system. To further investigate how the PDD method controls this evolution, special attention is given to the role of each PDD parameter. We show that glacial inception is critically dependent on the representation of the impact of the temperature variability from the daily to the inter-annual time scale, whose effect is modulated by the refreezing scheme. Finally, an additional set of sensitivity experiments has been carried out to assess the relative importance of melt processes with respect to initial ice sheet configuration in the construction and the evolution of past Northern Hemisphere ice sheets. Our analysis reveals that the impacts of the initial ice sheet condition may range from quite negligible to explaining about half of the LGM ice volume depending on the representation of stochastic temperature variations which remain the main driver of the evolution of the ice system.

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N2O Measurements on Air Extracted from Antarctic Ice Cores (Abstract)

Annals of Glaciology ◽

10.3189/s0260305500004699 ◽

1988 ◽

Vol 10 ◽

pp. 222-222

Author(s):

D. Zardini ◽

D. Raynaud ◽

D. Scharffe ◽

W. Seiler

Keyword(s):

Last Glacial Maximum ◽

Ice Cores ◽

Experimental Tests ◽

Glacial Maximum ◽

Recent Period ◽

Air Samples ◽

Last Glacial ◽

Original Procedure ◽

The Last Glacial Maximum ◽

The Last Glacial

A method has been developed for measuring N2O concentrations in the air extracted from the bubbles contained in ice cores. The air extraction is performed by cutting the ice into very small pieces with a rotating knife, in a controlled atmosphere. The N2O concentrations are measured by gas chromatography. The complete original procedure will be discussed, and the results of the different experimental tests given, with a discussion of the uncertainties.This method has been used to perform about 40 measurements on Antarctic ice samples. Ten air samples from the D57 core date approximately from the beginning of the seventeenth and twentieth centuries. The others were taken from the Dome C core and date from the Holocene and the period around the Last Glacial Maximum. The D57 results are in agreement with those of Pearman and others (1986), leading to a similar pre-industrial N2O level (270-290 ppb volume). Furthermore, our Dome C results suggest that during the Last Glacial Maximum atmospheric N2O content was not drastically different from the recent period.

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Sensitivity of simulated oxygen isotopes in ice cores and speleothems to Last Glacial Maximum surface conditions

10.5194/egusphere-egu21-2305 ◽

2021 ◽

Author(s):

André Paul ◽

Alexandre Cauquoin ◽

Stefan Mulitza ◽

Thejna Tharammal ◽

Martin Werner

Keyword(s):

Last Glacial Maximum ◽

General Circulation ◽

Ice Cores ◽

General Circulation Models ◽

Glacial Maximum ◽

Sea Surface ◽

Surface Conditions ◽

Last Glacial ◽

The Impact ◽

Mean Square Errors

In simulations of the climate during the Last Glacial Maximum (LGM), we employ two different isotope-enabled atmospheric general circulation models (NCAR iCAM3 and MPI ECHAM6-wiso) and use simulated (by coupled climate models) as well as reconstructed (from a new global climatology of the ocean surface duing the LGM, GLOMAP) surface conditions.The resulting atmospheric fields reflect the more pronounced structure and gradients in the reconstructions, for example, the precipitation is more depleted in oxygen-18 in the high latitudes and more enriched in low latitudes, especially in the tropical convective regions over the maritime continent in the equatorial Pacific and Indian Oceans and over the equatorial Atlantic Ocean. Furthermore, at the sites of ice cores and speleothems, the model-data fit improves in terms of the coefficients of determination and root-mean square errors.In additional sensitivity experiments, we also use the climatologies by Annan and Hargreaves (2013) and Tierney et al. (2020) and consider the impact of changes in reconstructed sea-ice extent and the global-mean sea-surface temperature.Our findings imply that the correct simulation or reconstruction of patterns and gradients in sea-surface conditions are crucial for a successful comparison to oxygen-isotope data from ice cores and speleothems.

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Methane in the climate system -- from the last glacial to the future

10.5194/egusphere-egu21-12440 ◽

2021 ◽

Author(s):

Thomas Kleinen ◽

Sergey Gromov ◽

Benedikt Steil ◽

Victor Brovkin

Keyword(s):

Radiative Forcing ◽

Ice Cores ◽

Future Climate ◽

Climate System ◽

Max Planck ◽

Atmospheric Concentration ◽

Methane Cycling ◽

Last Glacial ◽

The Future ◽

The Last Glacial

Between the last glacial maximum (LGM) and preindustrial times (PI), the atmospheric concentration of CH4, as shown by reconstructions from ice cores, roughly doubled. It then doubled again from PI to the present. Ice cores, however, cannot tell us how that development will continue in the future, and ice cores also cannot shed light on the causes of the rise in methane, as well as the rapid fluctuations during periods such as the Bolling-Allerod and Younger Dryas.We use a methane-enabled version of MPI-ESM, the Max Planck Institute for Meteorology Earth System Model, to investigate changes in methane cycling in a transient ESM experiment from the LGM to the present, continuing onwards into the future for the next millennium. The model is driven by prescribed orbit, greenhouse gases and ice sheets, with all other changes to the climate system determined internally. Methane cycling is modelled by modules representing the atmospheric transport and sink of methane, as well as terrestrial sources and sinks from soils, termites, and fires. Thus, the full natural methane cycle &#8211; with the exception of geological and animal emissions &#8211; is represented in the model. For historical and future climate, anthropogenic emissions of methane are considered, too.We show that the methane increase since the LGM is largely driven by source changes, with LGM emissions substantially reduced in comparison to the early Holocene and preindustrial states due to lower temperature, CO2, and soil carbon. Depending on the future climate scenario, these dependencies then lead to further increases in CH4, with a further doubling of atmospheric CH4 easily possible if one of the higher radiative forcing scenarios is followed. Furthermore, the future increases in CH4 will persist for a long time, as CH4 only decreases when the climate system cools again.

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Vostok, Antarctica, Ice Core: The Dust Record Over The Last Climatic Cycle (∼160 ka) (Abstract)

Annals of Glaciology ◽

10.3189/s0260305500006625 ◽

1988 ◽

Vol 11 ◽

pp. 204-204

Author(s):

L. Mounier ◽

J. R. Petit ◽

J. Jouzel ◽

C. Lorius ◽

Ye. S. Korotkevich ◽

...

Keyword(s):

Total Concentration ◽

Ice Core ◽

Ice Cores ◽

Optical Microscope ◽

Ice Age ◽

Maximum Temperature ◽

Temperature Changes ◽

Last Glacial ◽

Chemical Measurements ◽

The Last Glacial

The 2083 m Vostok Antarctic ice core provides a unique opportunity for access to many paleoclimatic and paleo-environmental proxy data. This core, which has been dated by using a glaciological model, fully covers the last glacial-interglacial cycle, and goes back to the ice age which preceded the last interglaciai (−160 ka B P ).A continuous deuterium record is now available and we have interpreted it in terms of local temperature changes. This record is dominated by the large 100 ka glacial-inter-glacial oscillation, with a maximum temperature amplitude of about 11°C; the long Last Glacial period is very well documented and it is confirmed that the warmest part of the Last Interglaciai period was about 2°C warmer than the Holocene. Comparison with the ice-volume marine record shows that the Vostok climate record is of relatively large geographical significance, which makes it possible to establish, over the last 160 ka, the link between worldwide climatic changes and the Vostok dust record that we present here.This dust content corresponds to the non-soluble microparticles. It was obtained on a discontinuous basis (1 sample = about ∼10 m). Due to the very low concentration of some samples (down to 20 x 10−9gg−1) and cracks in the ice from the first 1000 m depth, we used stringent decontamination procedures. Size distribution and total concentration were measured, using a Coulter counter and an optical microscope; the results were tested against chemical measurements (aluminium concentration). In previous studies, it has been shown that the main proportion of insoluble microparticles is of terrigenous origin and represents the small-sized (radius <2 μm) dust produced on the continents.The Vostok record displays an increase in dust concentration of up to 20 times during the coldest climatic periods, coupled with the presence of larger particles. It confirms, on a much longer time-scale, a characteristic previously noted in Antarctic and Greenland ice cores over the Last Glacial Maximum. This large increase is attributed to a greater areal extent of global tropical aridity during the cold periods, coupled with higher efficiency of atmospheric circulation in respect of dust production and transport. Beyond this, the relationship between the dust input and the successive stages during the Last Glacial is now very well documented and will be discussed with a view to correlating the Vostok climatic record with other marine and terrestrial paleodata.

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