Reef drowning during the last deglaciation: Evidence for catastrophic sea-level rise and ice-sheet collapse

Geology ◽  
1995 ◽  
Vol 23 (1) ◽  
pp. 4 ◽  
Author(s):  
Paul Blanchon ◽  
John Shaw
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Ice Sheet ◽  
Last Deglaciation ◽  
The Last Deglaciation

The Barents-Kara Ice Sheet response to the CMIP6-PMIP4 simulations for the LGM climate

2021 ◽  
Author(s):  
Victor van Aalderen ◽  
Sylvie Charbit ◽  
Christophe Dumas ◽  
Masa Kageyama
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Continuous Model ◽  
Last Deglaciation ◽  
Future Evolution ◽  
West Antarctic ◽  
The Last Deglaciation

<p>Recent observations show an acceleration of the glacier outflow in the West Antarctic ice sheet (WAIS) since the mid-1990s and an increase in calving events. Compared to the 1979-1990 period, mass loss from WAIS has been increased by a factor six between 2009 and 2017. The reduced buttressing effect from ice-shelf breakup may favour the ice flow from outlet glaciers and in turn the sea-level rise with potential noticeable consequences on human societies. However, despite continuous model improvements, large uncertainties are still present on the representation future evolution of the WAIS. The large panel of different results in the projections of the future sea-level rise stands, in part, to our misunderstanding of the process responsible for the marine ice sheet evolution. A possible approach to better constrain these processes, is to investigate past marine ice sheets, such as the Barents-Kara ice sheet (BKIS) at the Last Glacial Maximum (LGM), which can be considered, to a certain extent, as an analogue of the WAIS. Our objective is to study the processes responsible for the collapse of the BKIS during the last deglaciation. To simulate the evolution of the BKIS, we use the GRISLI ice-sheet model (20 km x 20 km) forced by different CMIP5/PMIP3 and CMIP6/PMIP4 models. We will present the response of the ice sheet to different types of atmospheric and oceanic forcing at the LGM coming from the PMIP models. This study represents a first step before studying more in depth the respective role of each climatic field but also the role of sea level rise coming from other LGM ice sheets in triggering the retreat of the BKIS at the beginning of the last deglaciation and the impacts of the dynamical processes.</p>

scholarly journals Decadal-scale onset and termination of Antarctic ice-mass loss during the last deglaciation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Michael E. Weber ◽  
Nicholas R. Golledge ◽  
Chris J. Fogwill ◽  
Chris S. M. Turney ◽  
Zoë A. Thomas
Keyword(s):  
Mass Loss ◽  
Sea Level Rise ◽  
Sea Level ◽  
Ross Sea ◽  
Ice Sheet ◽  
Rate Of Change ◽  
Last Deglaciation ◽  
Decadal Scale ◽  
Ice Sheet Modeling ◽  
Global Sea Level

AbstractEmerging ice-sheet modeling suggests once initiated, retreat of the Antarctic Ice Sheet (AIS) can continue for centuries. Unfortunately, the short observational record cannot resolve the tipping points, rate of change, and timescale of responses. Iceberg-rafted debris data from Iceberg Alley identify eight retreat phases after the Last Glacial Maximum that each destabilized the AIS within a decade, contributing to global sea-level rise for centuries to a millennium, which subsequently re-stabilized equally rapidly. This dynamic response of the AIS is supported by (i) a West Antarctic blue ice record of ice-elevation drawdown >600 m during three such retreat events related to globally recognized deglacial meltwater pulses, (ii) step-wise retreat up to 400 km across the Ross Sea shelf, (iii) independent ice sheet modeling, and (iv) tipping point analysis. Our findings are consistent with a growing body of evidence suggesting the recent acceleration of AIS mass loss may mark the beginning of a prolonged period of ice sheet retreat and substantial global sea level rise.

scholarly journals Late glacial to early Holocene development of southern Kattegat

1969 ◽  
Vol 28 ◽  
pp. 21-24 ◽  
Author(s):  
Carina Bendixen ◽  
Jørn Bo Jensen ◽  
Ole Bennike ◽  
Lars Ole Boldreel
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Late Glacial ◽  
Last Deglaciation ◽  
Isostatic Rebound ◽  
North East ◽  
The North ◽  
Tectonically Active ◽  
The Last Deglaciation ◽  
The Øresund Region

The Kattegat region is located in the wrench zone between the Fennoscandian shield and the Danish Basin that has repeatedly been tectonically active. The latest ice advances during the Quaternary in the southern part of Kattegat were from the north-east, east and south-east (Larsen et al. 2009). The last deglaciation took place at c. 18 to 17 ka BP (Lagerlund & Houmark-Nielsen 1993; Houmark-Nielsen et al. 2012) and was followed by inundation of the sea that formed a palaeo-Kattegat (Conradsen 1995) with a sea level that was relatively high because of glacio-isostatic depression. Around 17 ka BP, the ice margin retreated to the Øresund region and meltwater from the retreating ice drained into Kattegat. Over the next millennia, the region was characterised by regression because the isostatic rebound of the crust surpassed the ongoing eustatic sea-level rise, and a regional lowstand followed at the late glacial to Holocene transition (Mörner 1969; Thiede 1987; Lagerlund & Houmark-Nielsen 1993; Jensen et al. 2002a, b).

scholarly journals Cancelation of Deglacial Thermosteric Sea Level Rise by a Barosteric Effect

2020 ◽  
Vol 50 (12) ◽  
pp. 3623-3639
Author(s):  
Geoffrey Gebbie
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Steric Effect ◽  
Three Dimensional ◽  
Steric Effects ◽  
Last Deglaciation ◽  
Effect Analysis ◽  
Height Change ◽  
The Last Deglaciation ◽  
The Last Glacial

AbstractSea level rise over the last deglaciation is dominated by the mass of freshwater added to the oceans by the melting of the great ice sheets. While the steric effect of changing seawater density is secondary over the last 20 000 years, processes connected to deglacial warming, the redistribution of salt, and the pressure load of meltwater all influence sea level rise by more than a meter. Here we develop a diagnostic for steric effects that is valid when oceanic mass is changing. This diagnostic accounts for seawater compression due to the added overlying pressure of glacial meltwater, which is here defined to be a barosteric effect. Analysis of three-dimensional global seawater reconstructions of the last deglaciation indicates that thermosteric height change (1.0–1.5 m) is counteracted by barosteric (−1.9 m) and halosteric (from −0.4 to 0.0 m) effects. The total deglacial steric effect from −0.7 to −1.1 m has the opposite sign of analyses that assume that thermosteric expansion is dominant. Despite the vertical oceanic structure not being well constrained during the Last Glacial Maximum, net seawater contraction appears robust as it occurs in four reconstructions that were produced using different paleoceanographic datasets. Calculations that do not account for changes in ocean pressure give the misleading impression that steric effects enhanced deglacial sea level rise.

scholarly journals GEOCENTRIC MEAN SEA LEVEL FIELDS AT THE GERMAN NORTH SEA AND BALTIC COAST

2018 ◽  
pp. 21
Author(s):  
Jessica Kelln ◽  
Sönke Dangendorf ◽  
Jürgen Jensen ◽  
Justus Patzke ◽  
Wolfgang Niemeier ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Tide Gauge ◽  
Last Deglaciation ◽  
Mean Sea Level ◽  
Baltic Coast ◽  
Vertical Land Motion ◽  
Level Information ◽  
The Last Deglaciation ◽  
Global Mean Sea Level

Global mean sea level has risen over the 20th century (Hay et al. 2015; Dangendorf et al. 2017) and under sustained greenhouse gas emissions it is projected to further accelerate throughout the 21st century (Church et al. 2013) with large spatial variations, significantly threatening coastal communities. Locally the effects of geocentric (sometimes also referred to absolute) sea level rise can further be amplified by vertical land motion (VLM) due to natural adjustments of the solid earth to the melting of the large ice-sheets during the last deglaciation (GIA) or local anthropogenic interventions such as groundwater or gas withdrawal (e.g. Santamaría-Gómez et al. 2017). Both, the observed and projected geocentric sea level rise as well as VLM are critically important for coastal planning and engineering, since only their combined effect determines the total threat of coastal flooding at specific locations. Furthermore, due large spatial variability of sea level, information is required not only at isolated tide gauge (TG) locations but also along the coastline stretches in between.

scholarly journals An Ancient Meltwater Pulse Raised Sea Levels by 18 Meters

Eos ◽  
2021 ◽  
Vol 102 ◽  
Author(s):  
Tim Hornyak
Keyword(s):  
North America ◽  
Sea Level Rise ◽  
Sea Level ◽  
Last Deglaciation ◽  
Sea Levels ◽  
The Last Deglaciation ◽  
New Research

Meltwater pulse 1A, a period of rapid sea level rise after the last deglaciation, was powered by melting ice from North America and Scandinavia, according to new research.

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