The influence of lateral Earth structure on glacial isostatic adjustment in Greenland

Milne, Glenn A.; Latychev, Konstantin; Schaeffer, A. J.; Crowley, John W.; Lecavalier, Benoit; Audette, Alexandre

doi:10.1093/gji/ggy189

Cited by 31 publications

(56 citation statements)

References 62 publications

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“…Low viscosity mantle will also enhance the strength of the stabilising effect of GIA on grounding line dynamics, highlighting the importance of considering such feedbacks when modelling the future evolution of the Antarctic Ice Sheet. A number of studies have successfully incorporated 3-D Earth structure into GIA models beneath modern ice sheets 56,143,144 , and it is now apparent that coupled modelling and inclusion of 3-D Earth structure should both be considered when modelling solid Earth-cryosphere feedbacks 15 . Such models are being developed 87 but further interdisciplinary work, combining modelling and observational approaches, is needed to calibrate such models and better understand controls on the evolution of the Antarctic Ice Sheet.…”

Section: Discussionmentioning

confidence: 99%

Solid Earth change and the evolution of the Antarctic Ice Sheet

et al. 2019

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Recent studies suggest that Antarctica has the potential to contribute up to ~15 m of sea-level rise over the next few centuries. The evolution of the Antarctic Ice Sheet is driven by a combination of climate forcing and non-climatic feedbacks. In this review we focus on feedbacks between the Antarctic Ice Sheet and the solid Earth, and the role of these feedbacks in shaping the response of the ice sheet to past and future climate changes. The growth and decay of the Antarctic Ice Sheet reshapes the solid Earth via isostasy and erosion. In turn, the shape of the bed exerts a fundamental control on ice dynamics as well as the position of the grounding line—the location where ice starts to float. A complicating issue is the fact that Antarctica is situated on a region of the Earth that displays large spatial variations in rheological properties. These properties affect the timescale and strength of feedbacks between ice-sheet change and solid Earth deformation, and hence must be accounted for when considering the future evolution of the ice sheet.

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Section: Discussionmentioning

confidence: 99%

Solid Earth change and the evolution of the Antarctic Ice Sheet

et al. 2019

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“…The modeled uplift rates and associated uncertainties from Milne et al (2018) are shown in Figure S4. These solutions account for part of the uncertainty associated with the lateral Earth structure and do not account for that associated with the deglaciation history.…”

Section: Gia and Residual Uplift Ratesmentioning

confidence: 99%

“…existing GIA models constrained by paleo RSL data generally do not fit the uplift rates corrected for the elastic loading effects (Khan et al, 2016;Milne et al, 2018;Simpson et al, 2011;.…”

mentioning

confidence: 99%

Decadal to Centennial Timescale Mantle Viscosity Inferred From Modern Crustal Uplift Rates in Greenland

Adhikari

Milne

Khan

et al. 2021

Geophysical Research Letters

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There are 57 permanent Global Navigation Satellite System (GNSS) stations placed on the bedrock along the periphery of the Greenland Ice Sheet (GrIS). This network of GNSS stations-known as GNET (Bevis et al., 2012;Khan et al., 2016)-provides point measurements of 3-D bedrock motion. Some of these stations have been in operation since 1995, providing a valuable data set for probing causal relationships between ice load and solid-Earth deformation over a range of timescales. Interannual, seasonal, or shorter timescale GNET signals are interpreted as an elastic response of the solid Earth to short-period surface mass changes in Greenland, including fluctuations in mass transport through outlet glaciers and atmospheric pressure variability (e.g., Adhikari et al., 2017;Bevis et al., 2012;Zhang et al., 2019). The bedrock uplift as measured by GNET is also shown to track the apparent acceleration of ice mass change that is ongoing in Greenland (Bevis et al., 2019). Geophysical interpretation of secular trends in vertical bedrock motion-henceforth termed "uplift rates"-is ambiguous (e.g., Khan et al., 2016;Milne et al., 2018;Simpson et al., 2011;. We seek to reduce this ambiguity through improved quantification of the relative contributions of contemporary and past load changes to the measured uplift rates, especially those associated with the emergence of Greenland from the Little Ice Age (LIA).

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“…The response of the elastic lithosphere happens instantaneously, while the response time of the viscous mantle lies between decades and tens of millennia, depending on both, the viscosity of the mantle and the wavelength of the change in load. While the Lingle-Clark model is not considering local changes to viscosity or lithosphere thickness (Milne et al, 2018;Mordret, 2018;Khan et al, 2016) and approximates the earth as a half space, the relatively small spatial extent of the simulation region allows for such an approximation.…”

Section: Earth Deformation Modelmentioning

confidence: 99%

“…In addition, the response time and strength of the bedrock to changes in ice load is determined by the mantle viscosity ν, Wahr et al, 2001;Peltier and Drummong, 2008;Larour et al, 2019;Huybrechts, 1996, 1998;Milne et al, 2018;Fleming and Lambeck, 2004;Lecavalier et al, 2014;Lambeck et al, 2014;Lau et al, 2016). Ice retreat itself is affected by the temperature anomaly, here varied between 1.5 K and 3.0 K global warming (note the arctic amplification of 150 % leading to higher local temperature anomalies).…”

Section: Choice Of Model Parametersmentioning

confidence: 99%

Dynamic regimes of the Greenland Ice Sheet emerging from interacting melt-elevation and glacial isostatic adjustment feedbacks

Zeitz

Haacker

Donges

et al. 2021

Preprint

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Abstract. The stability of the Greenland Ice Sheet under global warming is governed by a number of dynamic processes and interacting feedback mechanisms in the ice sheet, atmosphere and solid Earth. Here we study the long-term effects due to the interplay of the competing melt-elevation and glacial isostatic adjustment (GIA) feedbacks for different temperature step forcing experiments with a coupled ice-sheet and solid-Earth model. Our model results show that for warming levels above 2 °C, Greenland could become essentially ice-free on the long-term, mainly as a result of surface melting and acceleration of ice flow. These ice losses can be mitigated, however, in some cases with strong GIA feedback even promoting the partial recovery of the Greenland ice volume. We further explore the full-factorial parameter space determining the relative strengths of the two feedbacks: Our findings suggest distinct dynamic regimes of the Greenland Ice Sheets on the route to destabilization under global warming – from recovery, via quasi-periodic oscillations in ice volume to ice-sheet collapse. In the recovery regime, the initial ice loss due to warming is essentially reversed within 50,000 years and the ice volume stabilizes at 61–93 % of the present-day volume. For certain combinations of temperature increase, atmospheric lapse rate and mantle viscosity, the interaction of the GIA feedback and the melt-elevation feedback leads to self-sustained, long-term oscillations in ice-sheet volume with oscillation periods of tens to hundreds of thousands of years and oscillation amplitudes between 15–70 % of present-day ice volume. This oscillatory regime reveals a possible mode of internal climatic variability in the Earth system on time scales on the order of 100,000 years that may be excited by or synchronized with orbital forcing or interact with glacial cycles and other slow modes of variability. Our findings are not meant as scenario-based near-term projections of ice losses but rather providing insight into of the feedback loops governing the "deep future" and, thus, long-term resilience of the Greenland Ice Sheet.

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The influence of lateral Earth structure on glacial isostatic adjustment in Greenland

Cited by 31 publications

References 62 publications

Solid Earth change and the evolution of the Antarctic Ice Sheet

Solid Earth change and the evolution of the Antarctic Ice Sheet

Decadal to Centennial Timescale Mantle Viscosity Inferred From Modern Crustal Uplift Rates in Greenland

Dynamic regimes of the Greenland Ice Sheet emerging from interacting melt-elevation and glacial isostatic adjustment feedbacks

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