Exploring links between geodynamics and climate change

2021 ◽  
Author(s):  
Mark Hoggard ◽  
Fred Richards
Keyword(s):  
Climate Change ◽  
Sea Level ◽  
Sedimentary Cover ◽  
Ice Sheet ◽  
Careful Consideration ◽  
Dynamic Topography ◽  
Low Carbon ◽  
Level Indicator ◽  
Geological Processes ◽  
Warming World

<p>Combating global climate change remains one of the greatest challenges facing humanity in the coming decades. Whilst oceanographers, ice sheet dynamicists, and atmospheric modellers all have an obvious role to play in leading efforts to tackle this problem, there remain many aspects that require careful consideration and cross-disciplinary interaction in other areas of the geosciences. In this talk, I will use selected examples to illustrate important links between geodynamics and climate change, including improving our understanding of its potential impacts and mitigation. The first concerns the role of mantle convection in influencing palaeo sea-level records and ice sheet dynamics. For example, Pliocene interglacial periods are commonly invoked as potential climatic analogues for the near-future conditions expected in our warming world, but there is considerable uncertainty over the extent to which important sea-level indicator sites have been perturbed, post-deposition, by convection-induced dynamic topography. The second link involves the growing shortage of metals that are key to the manufacture of technologies for low-carbon energy generation and storage. Tackling this shortfall requires an improvement in our ability to locate new, high-grade metal deposits, particularly those buried beneath shallow sedimentary cover. Novel geodynamical insights into the geological processes responsible for ore genesis will form a core component of narrowing the exploration search-space, and we have recently demonstrated this approach for sediment-hosted metal deposits. Through these case studies, I will show that it is primarily through developing an environment of cross-disciplinary discussion and financial support that our community is most likely to progress in understanding the potential impacts of climate change and how we may mitigate against them. Although one of the least well-studied components, the solid Earth is increasingly being recognised as a critical part of the climate system. Researchers working in topics as diverse as rock mechanics, seismology, convection modelling, and geochemistry all have a crucial role to play.</p>

Reassessing the Contribution of West Antarctica to Last Interglacial Sea Level in Light of 3D Mantle Viscosity Structure

2021 ◽  
Author(s):  
Linda Pan ◽  
Evelyn M. Powell ◽  
Konstantin Latychev ◽  
Jerry X. Mitrovica ◽  
Jessica R. Creveling ◽  
...  
Keyword(s):  
Sea Level ◽  
Complex Structure ◽  
Ice Sheet ◽  
West Antarctica ◽  
Last Interglacial ◽  
West Antarctic Ice Sheet ◽  
West Antarctic ◽  
Low Viscosity ◽  
Global Mean Sea Level ◽  
Warming World

<p>Studies of peak global mean sea level (GMSL) during the Last Interglacial (LIG; 130-116 ka) commonly cite values ranging from ~2-5 m for the maximum contribution from grounded, marine-based sectors of the West Antarctic Ice Sheet (WAIS). However, this estimate neglects viscoelastic crustal uplift and the associated meltwater flux out of marine sectors as they are exposed, a contribution considered to be small and slowly-accumulating. This assumption should be revisited, as a range of evidence indicates that West Antarctica is underlain by shallow mantle of anomalously low viscosity. By incorporating this complex structure into a gravitationally self-consistent sea-level calculation, we find that GMSL differs substantially from previous estimates. Our results indicate that these estimates thus require a reassessment of the contribution to GMSL rise from WAIS collapse, as will ice sheet models that do not account for the uplift mechanism. This conclusion has important implications for the sea level budget not only during the LIG, but also for all previous interglacials and projections of GMSL change in the future warming world.  </p>

The Climate Vulnerabilities of Global Nuclear Power

2019 ◽  
Vol 19 (4) ◽  
pp. 3-13 ◽  
Author(s):  
Sarah M. Jordaan ◽  
Afreen Siddiqi ◽  
William Kakenmaster ◽  
Alice C. Hill
Keyword(s):  
Climate Change ◽  
Sea Level Rise ◽  
Sea Level ◽  
Nuclear Power ◽  
Power Plants ◽  
Extreme Event ◽  
International Standards ◽  
Plant Design ◽  
Low Carbon ◽  
And Sea Level

Nuclear power—a source of low-carbon electricity—is exposed to increasing risks from climate change. Intensifying storms, droughts, extreme precipitation, wildfires, higher temperatures, and sea-level rise threaten supply disruptions and facility damage. Approximately 64 percent of installed capacity commenced operation between thirty and forty-eight years ago, before climate change was considered in plant design or construction. Globally, 516 million people reside within a fifty mile (80 km) radius of at least one operating nuclear power plant, and 20 million reside within a ten mile (16 km) radius, and could face health and safety risks resulting from an extreme event induced by climate change. Roughly 41 percent of nuclear power plants operate near seacoasts, making them vulnerable to increasing storm intensity and sea-level rise. Inland plants face exposure to other climate risks, such as increasingly severe wildfires and warmer water temperatures. No entity has responsibility for conducting risk assessments that adequately evaluate the climate vulnerabilities of nuclear power and the subsequent threats to international energy security, the environment, and human health. A comprehensive risk assessment by international agencies and the development of national and international standards is necessary to mitigate risks for new and existing plants.

scholarly journals Modelled response of the volume and thickness of the Antarctic ice sheet to the advance of the grounded area

2010 ◽  
Vol 51 (55) ◽  
pp. 41-48 ◽  
Author(s):  
Fuyuki Saito ◽  
Ayako Abe-Ouchi
Keyword(s):  
Climate Change ◽  
Sea Level ◽  
Volume Change ◽  
Numerical Experiments ◽  
Ice Sheet ◽  
Ice Shelf ◽  
Antarctic Ice Sheet ◽  
Ice Shelves ◽  
Ice Volume ◽  
The Antarctic

AbstractNumerical experiments are performed for the Antarctic ice sheet to study the sensitivity of the ice volume to variations in the area of grounded ice and to changes in the climate during the most recent deglaciation. The effect of the variations in the grounded area is found to be the major source of changes in the ice volume, while the effect of climate change was minor. The maximum possible contribution of the ice-volume change to sea-level rise during the deglaciation is estimated to be 36 m, which covers most values estimated in previous studies. The effect of the advance of the ice-sheet margin over those regions not connected to the major ice shelves contributes one-third of the total ice-volume change, which is comparable to the effect of the grounding of the Filchner–Ronne Ice Shelf and the contribution of the Ross and Amery Ice Shelves together.

scholarly journals Large and irreversible future decline of the Greenland ice-sheet

2020 ◽  
Author(s):  
Jonathan M. Gregory ◽  
Steven E. George ◽  
Robin S. Smith
Keyword(s):  
Climate Change ◽  
Steady State ◽  
Sea Level ◽  
General Circulation ◽  
Initial Perturbation ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Circulation Model ◽  
Intergovernmental Panel ◽  
Recent Climate

Abstract. We have studied the evolution of the Greenland ice-sheet under a range of constant climates typical of those projected for the end of the present century, using a dynamical ice-sheet model (Glimmer) coupled to an atmospheric general circulation model (FAMOUS-ice AGCM). The ice-sheet surface mass balance (SMB) is simulated by the AGCM, including its dependence on altitude within AGCM gridboxes. Over millennia under a warmer climate, the ice-sheet reaches a new steady state, whose mass is correlated with the initial perturbation in SMB, and hence with the magnitude of global climate change imposed. For the largest global warming considered (about +5 K), the contribution to global-mean sea-level rise (GMSLR) is initially 2.7 mm yr−1, and the ice-sheet is eventually practically eliminated (giving over 7 m of GMSLR). For all RCP8.5 climates, final GMSLR exceeds 4 m. If recent climate were maintained, GMSLR would reach 1.5–2.5 m. Contrary to expectation from earlier work, we find no evidence for a threshold warming that divides scenarios in which the ice-sheet suffers little reduction from those which it is mostly lost. This is because the dominant effect is reduction of area, not reduction of surface altitude, and the geographical variation of SMB must be taken into account. The final steady state is achieved by withdrawal from the coast in some places, and a tendency for increasing SMB due to enhancement of cloudiness and snowfall over the remaining ice-sheet, through the effects of topographic change on atmospheric circulation. If late twentieth-century climate is restored, the ice-sheet will not regrow to its present extent, owing to such effects, once its mass has fallen below a threshold of about 4 m of sea-level equivalent. In that case, about 2 m of GMSLR would become irreversible. In order to avoid this outcome, anthropogenic climate change must be reversed before the ice-sheet has declined to the threshold mass, which would be reached in about 600 years at the highest rate of mass-loss within the likely range of the Fifth Assessment Report of the Intergovernmental Panel on Climate Change.

scholarly journals Uncertainty quantification of the multi-centennial response of the Antarctic Ice Sheet to climate change

2018 ◽  
Author(s):  
Kevin Bulthuis ◽  
Maarten Arnst ◽  
Sainan Sun ◽  
Frank Pattyn
Keyword(s):  
Climate Change ◽  
Sea Level Rise ◽  
Sea Level ◽  
Ice Sheet ◽  
Parametric Uncertainty ◽  
Antarctic Ice Sheet ◽  
West Antarctic Ice Sheet ◽  
Sources Of Uncertainty ◽  
West Antarctic ◽  
The Antarctic

Abstract. Ice loss from the Antarctic ice sheet (AIS) is expected to become the major contributor to sea-level rise in the next centuries. Projections of the AIS response to climate change based on numerical ice-sheet models remain challenging to establish due to the complexity of physical processes involved in ice-sheet dynamics, including instability mechanisms that can destabilise marine sectors with retrograde slopes. Moreover, uncertainties in ice-sheet models limit the ability to provide accurate sea-level rise projections. Here, we apply probabilistic methods to a hybrid ice-sheet model to investigate the influence of several sources of uncertainty, namely sources of uncertainty in atmospheric forcing, basal sliding, grounding-line flux parameterisation, calving, sub-shelf melting, ice-shelf rheology and bedrock relaxation, on the continental response of the Antarctic ice sheet to climate change over the next millennium. We provide probabilistic projections of sea-level rise and grounding-line retreat and we carry out stochastic sensitivity analyses to determine the most influential sources of uncertainty. We find that all sources of uncertainty, except perhaps the bedrock relaxation times, contribute to the uncertainty in the projections. We show that the sensitivity of the projections to uncertainties increases and the contribution of the uncertainty in sub-shelf melting to the uncertainty in the projections becomes more and more dominant as the scenario gets warmer. We show that the significance of the AIS contribution to sea-level rise is controlled by marine ice-sheet instability (MISI) in marine basins, with the biggest contribution stemming from the more vulnerable West Antarctic ice sheet. We find that, irrespectively of parametric uncertainty, the strongly mitigated RCP 2.6 scenario prevents the collapse of the West Antarctic ice sheet, that in both RCP 4.5 and RCP 6.0 scenarios the occurrence of MISI in marine basins is more sensitive to parametric uncertainty and that, almost irrespectively of parametric uncertainty, RCP 8.5 triggers the collapse of the West Antarctic ice sheet.

scholarly journals Global Mean Sea Level: Indicator of Climate Change?

Science ◽  
1983 ◽  
Vol 219 (4587) ◽  
pp. 997-997 ◽  
Author(s):  
J. HANSEN ◽  
V. GORNITZ ◽  
S. LEBEDEFF ◽  
E. MOORE
Keyword(s):  
Climate Change ◽  
Sea Level ◽  
Level Indicator ◽  
Mean Sea Level ◽  
Global Mean Sea Level ◽  
Global Mean

Reconciling reconstructions and simulations of the Greenland ice sheet and its climate during the Last Interglacial period

2020 ◽  
Author(s):  
Alexander Robinson ◽  
Emilie Capron ◽  
Jorge Alvarez-Solas ◽  
Michael Bender ◽  
Heiko Goelzer ◽  
...  
Keyword(s):  
Climate Change ◽  
Sea Level ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Ice Cores ◽  
Future Climate Change ◽  
Interglacial Period ◽  
Last Interglacial ◽  
Proxy Data ◽  
Last Interglacial Period

<p>There is still no consensus concerning the evolution of the Greenland ice sheet during the Last Interglacial period (LIG, 130-115 kyr ago). Ice cores indicate that the ice sheet survived over most of the continent. Proxy data indicate temperature anomalies of up to 6-8°C. However, under these conditions, models predict almost complete deglaciation. This paradox must be resolved to be able to quantify Greenland’s sea-level contribution during the LIG as well as to understand its sensitivity to future climate change. Here we analyze the available evidence and outline strategies to reconcile modeling and data efforts for Greenland during the LIG.</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.

Global Mean Sea Level: Indicator of Climate Change?

Science ◽  
1983 ◽  
Vol 219 (4587) ◽  
pp. 997-998 ◽  
Author(s):  
R. ETKINS ◽  
E. EPSTEIN
Keyword(s):  
Climate Change ◽  
Sea Level ◽  
Level Indicator ◽  
Mean Sea Level ◽  
Global Mean Sea Level ◽  
Global Mean

scholarly journals Greenland glaciers and the 'greenhouse effect', status 1991

1992 ◽  
Vol 155 ◽  
pp. 9-13
Author(s):  
R.J Braithwaite ◽  
N Reeh ◽  
A Weidick
Keyword(s):  
Climate Change ◽  
Sea Level ◽  
Global Climate Change ◽  
Greenhouse Effect ◽  
Global Climate ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Potential Hazard ◽  
High Latitudes ◽  
Public Concern

Possible global climate change caused by increased 'greenhouse effect' continues to be a matter of international public concern. In particular, a warmer climate is expected to cause increased melting of the Greenland ice sheet, and a rise in world sea level. The Greenland ice sheet is therefore a potential hazard for low-Iying countries. Climate warming may be apparent first, and with greatest magnitude, at high latitudes so that increased melting of the Greenland ice sheet could give early warning of global climate change. For these reasons, GGU and foreign organisations are studying Greenland glaciers in connection with the 'greenhouse effect' (Fig. 1). The present review updates the note by Braithwaite (1990).

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