Rapid ecosystem response to abrupt climate changes during the last glacial period in western Europe, 40–16 ka

Geology ◽  
2008 ◽  
Vol 36 (5) ◽  
pp. 407 ◽  
Author(s):  
Barbara Wohlfarth ◽  
Daniel Veres ◽  
Linda Ampel ◽  
Terri Lacourse ◽  
Maarten Blaauw ◽  
...  
Keyword(s):  
Western Europe ◽  
Climate Changes ◽  
Glacial Period ◽  
Ecosystem Response ◽  
Last Glacial Period ◽  
Last Glacial ◽  
The Last Glacial

scholarly journals Oceanic forcing of the Eurasian Ice Sheet on millennial time scales during the Last Glacial Period

2018 ◽  
Author(s):  
Jorge Alvarez-Solas ◽  
Rubén Banderas ◽  
Alexander Robinson ◽  
Marisa Montoya
Keyword(s):  
Time Scales ◽  
North Atlantic ◽  
Climate Changes ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Glacial Period ◽  
Last Glacial Period ◽  
Last Glacial ◽  
The Last Glacial ◽  
Millennial Scale

Abstract. The last glacial period (LGP; ca.110–10 ka BP) was marked by the existence of two types of abrupt climatic changes, Dansgaard-Oeschger (DO) and Heinrich (H) events. Although the mechanisms behind these are not fully understood, it is generally accepted that the presence of ice sheets played an important role in their occurrence. While an important effort has been made to investigate the dynamics and evolution of the Laurentide Ice Sheet (LIS) during this period, the Eurasian Ice Sheet (EIS) has not received much attention, in particular from a modeling perspective. However, meltwater discharge from this and other ice sheets surrounding the Nordic Seas is often implied as a potential cause of ocean instabilities that lead to glacial abrupt climate changes. Thus, a better understanding of its variations during the LGP is important to understand its role in glacial abrupt climate changes. Here we investigate the response of the EIS to millennial-scale climate variability during the LGP. We use a hybrid, three-dimensional, thermomechanical ice-sheet model that includes ice shelves and ice streams. The model is forced offline through a novel perturbative approach that includes the effect of both atmospheric and oceanic variations and provides a more realistic treatment of millennial-scale climatic variability than conventional methods. Our results show that the EIS responds with enhanced ice discharge in phase with interstadial warming in the North Atlantic when forced with surface ocean temperatures. Conversely, when subsurface ocean temperatures are used, enhanced ice discharge occurs both during stadials and at the beginning of the interstadials. Separating the atmospheric and oceanic effects demonstrates the major role of the ocean in controlling the dynamics of the EIS on millennial time scales. While the atmospheric forcing alone is only able to produce modest iceberg discharges, warming of the ocean leads to higher rates of iceberg discharges as a result of relatively strong basal melting at the margins of the ice sheet. Together with previous work, our results provide a consistent explanation for the response of the LIS and the EIS to glacial abrupt climate changes, and highlight the need for stronger constraints on the local North Atlantic behavior in order to improve our understanding of the ice sheet's glacial dynamics.

scholarly journals The ACER pollen and charcoal database: a global resource to document vegetation and fire response to abrupt climate changes during the last glacial period

2017 ◽  
Author(s):  
Maria Fernanda Sánchez Goñi ◽  
Stéphanie Desprat ◽  
Anne-Laure Daniau ◽  
Franck C. Bassinot ◽  
Josué M. Polanco-Martínez ◽  
...  
Keyword(s):  
Climate Changes ◽  
Radiometric Dating ◽  
Glacial Period ◽  
Last Glacial Period ◽  
Global Database ◽  
Last Glacial ◽  
Additional Information ◽  
Common Control ◽  
Event Stratigraphy ◽  
The Last Glacial

Abstract. Quaternary records provide an opportunity to examine the nature of the vegetation and fire responses to rapid past climate changes comparable in velocity and magnitude to those expected in the 21st century. The best documented examples of rapid climate change in the past are the warming events associated with the Dansgaard-Oeschger (D-O) cycles during the last glacial period, which were sufficiently large to have had a potential feedback through changes in albedo and greenhouse gas emissions on climate. Previous reconstructions of vegetation and fire changes during the D-O cycles used independently constructed age models, making it difficult to compare the changes between different sites and regions. Here we present the ACER (Abrupt Climate Changes and Environmental Responses) global database which includes 93 pollen records from the last glacial period (73–15 ka) with a temporal resolution better than 1,000 years, 32 of which also provide charcoal records. A harmonized and consistent chronology based on radiometric dating (14C, 234U/230Th, OSL, 40Ar/39Ar dated tephra layers) has been constructed for 86 of these records, although in some cases additional information was derived using common control points based on event stratigraphy. The ACER database compiles metadata including geospatial and dating information, pollen and charcoal counts and pollen percentages of the characteristic biomes, and is archived in Microsoft AccessTM at doi:10.1594/PANGAEA.870867.

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

2009 ◽  
Vol 71 (3) ◽  
pp. 385-396 ◽  
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.

scholarly journals The ACER pollen and charcoal database: a global resource to document vegetation and fire response to abrupt climate changes during the last glacial period

2017 ◽  
Vol 9 (2) ◽  
pp. 679-695 ◽  
Author(s):  
María Fernanda Sánchez Goñi ◽  
Stéphanie Desprat ◽  
Anne-Laure Daniau ◽  
Frank C. Bassinot ◽  
Josué M. Polanco-Martínez ◽  
...  
Keyword(s):  
Climate Changes ◽  
Radiometric Dating ◽  
Glacial Period ◽  
Last Glacial Period ◽  
Global Database ◽  
Last Glacial ◽  
Additional Information ◽  
Common Control ◽  
Event Stratigraphy ◽  
The Last Glacial

Abstract. Quaternary records provide an opportunity to examine the nature of the vegetation and fire responses to rapid past climate changes comparable in velocity and magnitude to those expected in the 21st-century. The best documented examples of rapid climate change in the past are the warming events associated with the Dansgaard–Oeschger (D–O) cycles during the last glacial period, which were sufficiently large to have had a potential feedback through changes in albedo and greenhouse gas emissions on climate. Previous reconstructions of vegetation and fire changes during the D–O cycles used independently constructed age models, making it difficult to compare the changes between different sites and regions. Here, we present the ACER (Abrupt Climate Changes and Environmental Responses) global database, which includes 93 pollen records from the last glacial period (73–15 ka) with a temporal resolution better than 1000 years, 32 of which also provide charcoal records. A harmonized and consistent chronology based on radiometric dating (14C, 234U∕230Th, optically stimulated luminescence (OSL), 40Ar∕39Ar-dated tephra layers) has been constructed for 86 of these records, although in some cases additional information was derived using common control points based on event stratigraphy. The ACER database compiles metadata including geospatial and dating information, pollen and charcoal counts, and pollen percentages of the characteristic biomes and is archived in Microsoft AccessTM at https://doi.org/10.1594/PANGAEA.870867.

Synchronous timing of abrupt climate changes during the last glacial period

Science ◽  
2020 ◽  
Vol 369 (6506) ◽  
pp. 963-969
Author(s):  
Ellen C. Corrick ◽  
Russell N. Drysdale ◽  
John C. Hellstrom ◽  
Emilie Capron ◽  
Sune Olander Rasmussen ◽  
...  
Keyword(s):  
Climate Changes ◽  
Ice Core ◽  
South American ◽  
Glacial Period ◽  
Last Glacial Period ◽  
Independent Evidence ◽  
Last Glacial ◽  
Mediterranean Regions ◽  
Regional Synchrony ◽  
The Last Glacial

Abrupt climate changes during the last glacial period have been detected in a global array of palaeoclimate records, but our understanding of their absolute timing and regional synchrony is incomplete. Our compilation of 63 published, independently dated speleothem records shows that abrupt warmings in Greenland were associated with synchronous climate changes across the Asian Monsoon, South American Monsoon, and European-Mediterranean regions that occurred within decades. Together with the demonstration of bipolar synchrony in atmospheric response, this provides independent evidence of synchronous high-latitude–to-tropical coupling of climate changes during these abrupt warmings. Our results provide a globally coherent framework with which to validate model simulations of abrupt climate change and to constrain ice-core chronologies.

Improving age models for abrupt climate changes during the last glacial by pattern recognition

2020 ◽  
Author(s):  
Mark Turner ◽  
Sandy Harrison
Keyword(s):  
Pattern Recognition ◽  
Goodness Of Fit ◽  
Climate Changes ◽  
Global Climate ◽  
Glacial Period ◽  
Last Glacial Period ◽  
Last Glacial ◽  
Global Climate Changes ◽  
Pollen Records ◽  
The Last Glacial

<p>Quaternary records provide an opportunity to examine how regional climates and vegetation reflect global climate changes comparable in magnitude and velocity to those expected during the 21st century.  The Dansgaard-Oeschger (D-O) cycles of the last glacial period provide the best documented examples of such rapid climate warmings (Greenland interstadials, GIs). However, the age models of pollen records that document regional responses to D-O events are, in general, poorly constrained beyond the radiocarbon timescale. Here we use a pattern-recognition approach, based on matching oscillations in palaeoclimate records to a template of D-O events seen in the Greenland record, to provide better constrained age models. We create a series of templates of Greenland Interstadials (GIs) and compare these to a normalised and detrended time series from a target record using a sliding window and measuring goodness-of-fit using Euclidian distance. We show that this approach can identify D-O events in well-dated records, including reproducing the Greenland record itself. We then apply this approach to the less well-constrained pollen records from the last glacial period from southern Europe. The re-aligned age models permit a more robust comparison of the reconstructed vegetation and climate changes through time and across sites, allowing for regional differences in the response to individual GIs to be identified.</p>

scholarly journals Were last glacial climate events simultaneous between Greenland and western Europe?

2008 ◽  
Vol 4 (5) ◽  
pp. 1203-1217 ◽  
Author(s):  
M. Blaauw ◽  
B. Wohlfarth ◽  
J. A. Christen ◽  
L. Ampel ◽  
D. Veres ◽  
...  
Keyword(s):  
Western Europe ◽  
Ice Cores ◽  
Glacial Period ◽  
Last Glacial Period ◽  
Climate Fluctuations ◽  
Last Glacial ◽  
Ice Cap ◽  
Climate Events ◽  
Glacial Climate ◽  
The Last Glacial

Abstract. During the last glacial period, several large abrupt climate fluctuations took place on the Greenland ice cap and elsewhere. Often these Dansgaard/Oeschger events are assumed to have been synchronous, and then used as tie-points to link chronologies between the proxy archives. However, if temporally separate events are lumped into one illusionary event, climatic interpretations of the tuned events will obviously be flawed. Here, we compare Dansgaard/Oeschger-type events in a well-dated record from south-eastern France with those in Greenland ice cores. Instead of assuming simultaneous climate events between both archives, we keep their age models independent. Even these well-dated archives possess large chronological uncertainties, that prevent us from inferring synchronous climate events at decadal to multi-centennial time scales. If possible, tuning of proxy archives should be avoided.

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