scholarly journals Palaeo-sea-level and palaeo-ice-sheet databases: problems, strategies, and perspectives

2016 ◽  
Vol 12 (4) ◽  
pp. 911-921 ◽  
Author(s):  
André Düsterhus ◽  
Alessio Rovere ◽  
Anders E. Carlson ◽  
Benjamin P. Horton ◽  
Volker Klemann ◽  
...  
Keyword(s):  
Sea Level ◽  
Research Question ◽  
Ice Sheet ◽  
Original Data ◽  
Sea Levels ◽  
The Earth ◽  
Geological Features ◽  
Funding Agencies ◽  
The Creation ◽  
Objective Description

Abstract. Sea-level and ice-sheet databases have driven numerous advances in understanding the Earth system. We describe the challenges and offer best strategies that can be adopted to build self-consistent and standardised databases of geological and geochemical information used to archive palaeo-sea-levels and palaeo-ice-sheets. There are three phases in the development of a database: (i) measurement, (ii) interpretation, and (iii) database creation. Measurement should include the objective description of the position and age of a sample, description of associated geological features, and quantification of uncertainties. Interpretation of the sample may have a subjective component, but it should always include uncertainties and alternative or contrasting interpretations, with any exclusion of existing interpretations requiring a full justification. During the creation of a database, an approach based on accessibility, transparency, trust, availability, continuity, completeness, and communication of content (ATTAC3) must be adopted. It is essential to consider the community that creates and benefits from a database. We conclude that funding agencies should not only consider the creation of original data in specific research-question-oriented projects, but also include the possibility of using part of the funding for IT-related and database creation tasks, which are essential to guarantee accessibility and maintenance of the collected data.

Observations of postglacial uplift at Churchill, Manitoba

1992 ◽  
Vol 29 (11) ◽  
pp. 2418-2425 ◽  
Author(s):  
A. Mark Tushingham
Keyword(s):  
Sea Level ◽  
Tide Gauge ◽  
Ice Sheet ◽  
Laurentide Ice Sheet ◽  
Glacial Isostatic Adjustment ◽  
Tide Gauge Record ◽  
Isostatic Adjustment ◽  
Absolute Gravimetry ◽  
The Earth ◽  
Level Data

Churchill, Manitoba, is located near the centre of postglacial uplift caused by the Earth's recovery from the melting of the Laurentide Ice Sheet. The value of present-day uplift at Churchill has important implications in the study of postglacial uplift in that it can aid in constraining the thickness of the ice sheet and the rheology of the Earth. The tide-gauge record at Churchill since 1940 is examined, along with nearby Holocene relative sea-level data, geodetic measurements, and recent absolute gravimetry measurements, and a present-day rate of uplift of 8–9 mm/a is estimated. Glacial isostatic adjustment models yield similar estimates for the rate of uplift at Churchill. The effects of the tide-gauge record of the diversion of the Churchill River during the mid-1970's are discussed.

Past Sea Levels, Eustasy and Deformation of the Earth

1972 ◽  
Vol 2 (1) ◽  
pp. 1-14 ◽  
Author(s):  
R. I. Walcott
Keyword(s):  
Sea Level ◽  
Late Glacial ◽  
The United States ◽  
Ground Subsidence ◽  
Postglacial Rebound ◽  
Vertical Movements ◽  
Sea Levels ◽  
Atlantic Seaboard ◽  
The Earth ◽  
Change In Mean

Vertical movements of the earth's surface related to postglacial rebound, the eustatic rise in sea level and the elastic deformation of the globe due to melting of late glacial ice sheets are calculated for simplified models of the earth. The movements of the ground are large and require a reevaluation of what is meant by eustatic sea level change. This is defined here as an ocean-wide average change in mean sea level and its measurement requires widely distributed observations weighted according to the areas of oceans they represent. Evidence of a postglacial (6000-0 years BP) relative rise in sea level comes largely from regions affected by ground subsidence related to adjacent upward postglacial rebound movements in deglaciated areas: evidence for a relative fall of sea level comes from coastlines well removed from areas of rebound and which have been affected by a rise of the continental areas through compensation for the eustatic load. It is concluded: (1) no substantial eustatic change of sea level in the past 6,000 years is required to explain postglacial sea levels: (2) in late glacial time the eustatic curve is probably more like the sea level curve of Texas and Mexico than that of the Atlantic seaboard of the United States: (3) that the information of past sea levels, when sufficiently widespread, can provide an important method of studying the deep mechanical structure of the earth.

Modelling the Antarctic Ice Sheet in the warm Mid-Pliocene

2020 ◽  
Author(s):  
James O'Neill ◽  
Tamsin Edwards ◽  
Lauren Gregoire ◽  
Niall Gandy ◽  
Aisling Dolan ◽  
...  
Keyword(s):  
Sea Level ◽  
Climate Models ◽  
Phase 1 ◽  
Ice Sheet ◽  
Latin Hypercube Design ◽  
Antarctic Ice Sheet ◽  
Sea Levels ◽  
Ocean Climate ◽  
Parameter Values ◽  
The Antarctic

<p>The Antarctic ice sheet is a deeply uncertain component of future sea level under anthropogenic climate change. To shed light on the ice sheets response to warmer climates in the past and its’ response to future warming, periods in Earth’s geological record can serve as instructive modelling targets. The mid-Pliocene warm period (3.3 – 3.0 Ma) is characterised by global mean surface temperatures ~2.7-4<sup>o</sup>C above pre-industrial, atmospheric CO<sub>2</sub> concentrations of ~400ppm and eustatic sea level rise on the order of ~10-30m above modern. The mid-Pliocene sea level record is subject to large uncertainties. The upper end of this record implies a significant contribution from Antarctica and possible collapse of regions of the ice sheet, driven by marine ice sheet instabilities.</p><p>We present a suite of BISICLES ice sheet model simulations, forced with a subset of Pliocene Modelling Intercomparison Project (PlioMIP phase 1) coupled atmosphere-ocean climate models, that represent the Pliocene Antarctic ice sheet. This ensemble captures a range of possible ice sheet model responses to a warm Pliocene-like climate under different parameter choices, sampled in a Latin hypercube design. Modelled Antarctic sea level contribution is compared to reconstructions of Pliocene sea level, to explore the extent to which available data with large uncertainties can constrain the model parameter values.</p><p>Our aim with this work is to provide insights on Antarctic contribution to sea level in the warm mid-Pliocene. We seek to characterise the role of ice-ocean, ice-atmosphere and ice-bedrock parameter uncertainty in BISICLES on the ice sheet sea level contribution range, and whether cliff instability processes are necessary in reproduce high Pliocene sea levels in this ice sheet model.</p>

Trends and projections in ice sheet mass balance

2020 ◽  
Author(s):  
Andrew Shepherd ◽  
Keyword(s):  
Mass Balance ◽  
Sea Level Rise ◽  
Sea Level ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Ice Dynamics ◽  
Surface Mass ◽  
Sea Levels ◽  
Global Sea Level

<p>In recent decades, the Antarctic and Greenland Ice Sheets have been major contributors to global sea-level rise and are expected to be so in the future. Although increases in glacier flow and surface melting have been driven by oceanic and atmospheric warming, the degree and trajectory of today’s imbalance remain uncertain. Here we compare and combine 26 individual satellite records of changes in polar ice sheet volume, flow and gravitational potential to produce a reconciled estimate of their mass balance. <strong>Since the early 1990’s, ice losses from Antarctica and Greenland have caused global sea-levels to rise by 18.4 millimetres, on average, and there has been a sixfold increase in the volume of ice loss over time. Of this total, 41 % (7.6 millimetres) originates from Antarctica and 59 % (10.8 millimetres) is from Greenland. In this presentation, we compare our reconciled estimates of Antarctic and Greenland ice sheet mass change to IPCC projection of sea level rise to assess the model skill in predicting changes in ice dynamics and surface mass balance.  </strong>Cumulative ice losses from both ice sheets have been close to the IPCC’s predicted rates for their high-end climate warming scenario, which forecast an additional 170 millimetres of global sea-level rise by 2100 when compared to their central estimate.</p>

3D glacial-isostatic adjustment models using geodynamically constrained Earth structures

2021 ◽  
Author(s):  
Meike Bagge ◽  
Volker Klemann ◽  
Bernhard Steinberger ◽  
Milena Latinović ◽  
Maik Thomas
Keyword(s):  
Solid Earth ◽  
Sea Level ◽  
Ice Sheet ◽  
Sea Level Change ◽  
Glacial Isostatic Adjustment ◽  
Level Change ◽  
Isostatic Adjustment ◽  
Mantle Viscosity ◽  
The Earth ◽  
Earth Structures

<p>The interaction between ice sheets and the solid Earth plays an important role for ice-sheet stability and sea-level change and hence for global climate models. Glacial-isostatic adjustment (GIA) models enable simulation of the solid Earth response due to variations in ice-sheet and ocean loading and prediction of the relative sea-level change. Because the viscoelastic response of the solid Earth depends on both ice-sheet distribution and the Earth’s rheology, independent constraints for the Earth structure in GIA models are beneficial. Seismic tomography models facilitate insights into the Earth’s interior, revealing lateral variability of the mantle viscosity that allows studying its relevance in GIA modeling. Especially, in regions of low mantle viscosity, the predicted surface deformations generated with such 3D GIA models differ considerably from those generated by traditional GIA models with radially symmetric structures. But also, the conversion from seismic velocity variations to viscosity is affected by a set of uncertainties. Here, we apply geodynamically constrained 3D Earth structures. We analyze the impact of conversion parameters (reduction factor in Arrhenius law and radial viscosity profile) on relative sea-level predictions. Furthermore, we focus on exemplary low-viscosity regions like the Cascadian subduction zone and southern Patagonia, which coincide with significant ice-mass changes.</p>

scholarly journals A new sea-level record for the Neogene/Quaternary boundary reveals transition to a more stable East Antarctic Ice Sheet

2020 ◽  
Vol 117 (49) ◽  
pp. 30980-30987
Author(s):  
Kim A. Jakob ◽  
Paul A. Wilson ◽  
Jörg Pross ◽  
Thomas H. G. Ezard ◽  
Jens Fiebig ◽  
...  
Keyword(s):  
Sea Level ◽  
Northern Hemisphere ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Deep Ocean ◽  
Antarctic Ice Sheet ◽  
Sea Levels ◽  
Ice Volume ◽  
Warming World ◽  
East Antarctic Ice Sheet

Sea-level rise resulting from the instability of polar continental ice sheets represents a major socioeconomic hazard arising from anthropogenic warming, but the response of the largest component of Earth’s cryosphere, the East Antarctic Ice Sheet (EAIS), to global warming is poorly understood. Here we present a detailed record of North Atlantic deep-ocean temperature, global sea-level, and ice-volume change for ∼2.75 to 2.4 Ma ago, when atmospheric partial pressure of carbon dioxide (pCO2) ranged from present-day (>400 parts per million volume, ppmv) to preindustrial (<280 ppmv) values. Our data reveal clear glacial–interglacial cycles in global ice volume and sea level largely driven by the growth and decay of ice sheets in the Northern Hemisphere. Yet, sea-level values during Marine Isotope Stage (MIS) 101 (∼2.55 Ma) also signal substantial melting of the EAIS, and peak sea levels during MIS G7 (∼2.75 Ma) and, perhaps, MIS G1 (∼2.63 Ma) are also suggestive of EAIS instability. During the succeeding glacial–interglacial cycles (MIS 100 to 95), sea levels were distinctly lower than before, strongly suggesting a link between greater stability of the EAIS and increased land-ice volumes in the Northern Hemisphere. We propose that lower sea levels driven by ice-sheet growth in the Northern Hemisphere decreased EAIS susceptibility to ocean melting. Our findings have implications for future EAIS vulnerability to a rapidly warming world.

scholarly journals Resilience in the Face of Sea Level Rise: An Architectural Response to Rising Sea Levels in Wellington, New Zealand

2021 ◽  
Author(s):  
◽  
Michael Barrington Hatch
Keyword(s):  
Climate Change ◽  
Sea Level Rise ◽  
Sea Level ◽  
Global Climate ◽  
Research Question ◽  
Capital City ◽  
Direct Result ◽  
Sea Levels ◽  
Coastal City ◽  
The Face

<p>Climate change is widely regarded as the leading global issue of the 21st century. There is now a general international agreement, supported by an overwhelming amount of scientific evidence, that the global climate is changing at an accelerated rate and that human-driven emissions of greenhouse gases into the atmosphere is the main factor driving this trend. Arguably the most devastating impact of climate change on the human civilisation will be a rapidly increasing rise in global sea levels, which are currently rising at an unprecedented rate, placing hundreds of millions of people at serious risk of inundation in coastal communities across the globe. In the case of New Zealand’s capital city, Wellington, over ten percent of the city’s residents are at risk of displacement by the end of this century. This thesis aims to find a solution to resident displacement in the coastal city, addressing the question, How can a resilient residential dwelling be designed for the coastal city, in response to the encroaching pressures of climate change driven sea level rise? This research question and its subsequent design aims have been achieved through a highly iterative design process resulting the development of a connected network of amphibious dwelling solutions which provide the residents of the selected focus community of Kilbirnie, a coastal suburb in Wellington city, with the capacity to accommodate, adapt and thrive in the face of sea inundation. Hereby ensuring the social sustainability of the coastal community, currently at serious risk of displacement as a direct result of climate change driven sea level rise.</p>

scholarly journals Resilience in the Face of Sea Level Rise: An Architectural Response to Rising Sea Levels in Wellington, New Zealand

2021 ◽  
Author(s):  
◽  
Michael Barrington Hatch
Keyword(s):  
Climate Change ◽  
Sea Level Rise ◽  
Sea Level ◽  
Global Climate ◽  
Research Question ◽  
Capital City ◽  
Direct Result ◽  
Sea Levels ◽  
Coastal City ◽  
The Face

<p>Climate change is widely regarded as the leading global issue of the 21st century. There is now a general international agreement, supported by an overwhelming amount of scientific evidence, that the global climate is changing at an accelerated rate and that human-driven emissions of greenhouse gases into the atmosphere is the main factor driving this trend. Arguably the most devastating impact of climate change on the human civilisation will be a rapidly increasing rise in global sea levels, which are currently rising at an unprecedented rate, placing hundreds of millions of people at serious risk of inundation in coastal communities across the globe. In the case of New Zealand’s capital city, Wellington, over ten percent of the city’s residents are at risk of displacement by the end of this century. This thesis aims to find a solution to resident displacement in the coastal city, addressing the question, How can a resilient residential dwelling be designed for the coastal city, in response to the encroaching pressures of climate change driven sea level rise? This research question and its subsequent design aims have been achieved through a highly iterative design process resulting the development of a connected network of amphibious dwelling solutions which provide the residents of the selected focus community of Kilbirnie, a coastal suburb in Wellington city, with the capacity to accommodate, adapt and thrive in the face of sea inundation. Hereby ensuring the social sustainability of the coastal community, currently at serious risk of displacement as a direct result of climate change driven sea level rise.</p>

scholarly journals Dynamic response of Antarctic Peninsula Ice Sheet to collapse of Larsen C and George VI ice shelves

2018 ◽  
Author(s):  
Clemens Schannwell ◽  
Stephen Cornford ◽  
David Pollard ◽  
Nicholas Edward Barrand
Keyword(s):  
Dynamic Response ◽  
Sea Level ◽  
Antarctic Peninsula ◽  
Ice Sheet ◽  
Ice Shelf ◽  
Ice Shelves ◽  
Sea Levels ◽  
The Past ◽  
Speed Up ◽  
Global Sea Level

Abstract. Ice shelf break-up and disintegration events over the past several decades have led to speed-up, thinning, and retreat of upstream tributary glaciers and increases to rates of global sea-level rise. The southward progression of these episodes indicates a climatic cause, and in turn suggests that the larger Larsen C and George VI ice shelves may undergo similar collapse in future. However, the extent to which removal of Larsen C and George VI ice shelves will affect upstream tributary glaciers and add to global sea levels is unknown. Here we apply numerical ice-sheet models of varying complexity to show that the centennial sea-level commitment of Larsen C embayment glaciers following immediate shelf collapse is low (

scholarly journals Dynamic response of Antarctic Peninsula Ice Sheet to potential collapse of Larsen C and George VI ice shelves

2018 ◽  
Vol 12 (7) ◽  
pp. 2307-2326 ◽  
Author(s):  
Clemens Schannwell ◽  
Stephen Cornford ◽  
David Pollard ◽  
Nicholas E. Barrand
Keyword(s):  
Sea Level ◽  
Antarctic Peninsula ◽  
Ice Sheet ◽  
Ice Shelf ◽  
Ice Shelves ◽  
Sea Levels ◽  
The Past ◽  
Large Size ◽  
Speed Up ◽  
Global Sea Level

Abstract. Ice shelf break-up and disintegration events over the past 5 decades have led to speed-up, thinning, and retreat of upstream tributary glaciers and increases to rates of global sea-level rise. The southward progression of these episodes indicates a climatic cause and in turn suggests that the larger Larsen C and George VI ice shelves may undergo a similar collapse in the future. However, the extent to which removal of the Larsen C and George VI ice shelves will affect upstream tributary glaciers and add to global sea levels is unknown. Here we apply numerical ice-sheet models of varying complexity to show that the centennial sea-level commitment of Larsen C embayment glaciers following immediate shelf collapse is low (<2.5 mm to 2100, <4.2 mm to 2300). Despite its large size, Larsen C does not provide strong buttressing forces to upstream basins and its collapse does not result in large additional discharge from its tributary glaciers in any of our model scenarios. In contrast, the response of inland glaciers to a collapse of the George VI Ice Shelf may add up to 8 mm to global sea levels by 2100 and 22 mm by 2300 due in part to the mechanism of marine ice sheet instability. Our results demonstrate the varying and relative importance to sea level of the large Antarctic Peninsula ice shelves considered to present a risk of collapse.

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