scholarly journals Quantification of the Greenland ice sheet contribution to Last Interglacial sea-level rise

2012 ◽  
Vol 8 (4) ◽  
pp. 2731-2776 ◽  
Author(s):  
E. J. Stone ◽  
D. J. Lunt ◽  
J. D. Annan ◽  
J. C. Hargreaves
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
The Arctic ◽  
Substantial Contribution ◽  
Orbital Forcing ◽  
Last Interglacial ◽  
Ice Melt ◽  
A Value

Abstract. The Last Interglaciation (~ 130–115 thousand years ago) was a time when the Arctic climate was warmer than today (Anderson et al., 2006; Kaspar et al., 2005) and sea-level extremely likely at least 6 m higher (Kopp et al., 2009). However, there is large uncertainty in the relative contributions to this sea-level rise from the Greenland and Antarctic ice sheets and smaller icefields (Otto-Bliesner et al., 2006; Huybrechts, 2002; Letréguilly et al., 1991; Ritz et al., 1997; Cuffey and Marshall, 2000; Tarasov and Peltier, 2003; Lhomme et al., 2005; Greve, 2005; Robinson et al., 2011; Fyke et al., 2011). By performing an ensemble of 500 coupled climate – ice sheet model simulations, constrained by paleo-data, we determine probabilistically the likely contribution of Greenland ice sheet melt to Last Interglacial sea-level rise, taking into account model uncertainty. Here we show a 90% probability that Greenland ice melt contributed at least 0.6 m but less than 10% probability it exceeded 3.5 m, a value which is lower than several recent estimates (Cuffey and Marshall, 2000; Tarasov and Peltier, 2003; Lhomme et al., 2005; Robinson et al., 2011). Our combined modelling and paleo-data approach suggests that the Greenland ice sheet is less sensitive to orbital forcing than previously thought, and implicates Antarctic melt as providing a substantial contribution to Last Interglacial sea-level rise.

scholarly journals Quantification of the Greenland ice sheet contribution to Last Interglacial sea level rise

2013 ◽  
Vol 9 (2) ◽  
pp. 621-639 ◽  
Author(s):  
E. J. Stone ◽  
D. J. Lunt ◽  
J. D. Annan ◽  
J. C. Hargreaves
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Climate Model ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Ice Cores ◽  
The Arctic ◽  
Substantial Contribution ◽  
Interglacial Period ◽  
Last Interglacial

Abstract. During the Last Interglacial period (~ 130–115 thousand years ago) the Arctic climate was warmer than today, and global mean sea level was probably more than 6.6 m higher. However, there are large discrepancies in the estimated contributions to this sea level change from various sources (the Greenland and Antarctic ice sheets and smaller ice caps). Here, we determine probabilistically the likely contribution of Greenland ice sheet melt to Last Interglacial sea level rise, taking into account ice sheet model parametric uncertainty. We perform an ensemble of 500 Glimmer ice sheet model simulations forced with climatologies from the climate model HadCM3, and constrain the results with palaeodata from Greenland ice cores. Our results suggest a 90% probability that Greenland ice melt contributed at least 0.6 m, but less than 10% probability that it exceeded 3.5 m, a value which is lower than several recent estimates. Many of these previous estimates, however, did not include a full general circulation climate model that can capture atmospheric circulation and precipitation changes in response to changes in insolation forcing and orographic height. Our combined modelling and palaeodata approach suggests that the Greenland ice sheet is less sensitive to orbital forcing than previously thought, and it implicates Antarctic melt as providing a substantial contribution to Last Interglacial sea level rise. Future work should assess additional uncertainty due to inclusion of basal sliding and the direct effect of insolation on surface melt. In addition, the effect of uncertainty arising from climate model structural design should be taken into account by performing a multi-climate-model comparison.

scholarly journals Greenland ice sheet contribution to sea level rise during the last interglacial period: a modelling study driven and constrained by ice core data

2013 ◽  
Vol 9 (1) ◽  
pp. 353-366 ◽  
Author(s):  
A. Quiquet ◽  
C. Ritz ◽  
H. J. Punge ◽  
D. Salas y Mélia
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Ice Core ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Interglacial Period ◽  
Last Interglacial ◽  
Intergovernmental Panel ◽  
Orbital Configuration ◽  
Global Sea Level

Abstract. As pointed out by the forth assessment report of the Intergovernmental Panel on Climate Change, IPCC-AR4 (Meehl et al., 2007), the contribution of the two major ice sheets, Antarctica and Greenland, to global sea level rise, is a subject of key importance for the scientific community. By the end of the next century, a 3–5 °C warming is expected in Greenland. Similar temperatures in this region were reached during the last interglacial (LIG) period, 130–115 ka BP, due to a change in orbital configuration rather than to an anthropogenic forcing. Ice core evidence suggests that the Greenland ice sheet (GIS) survived this warm period, but great uncertainties remain about the total Greenland ice reduction during the LIG. Here we perform long-term simulations of the GIS using an improved ice sheet model. Both the methodologies chosen to reconstruct palaeoclimate and to calibrate the model are strongly based on proxy data. We suggest a relatively low contribution to LIG sea level rise from Greenland melting, ranging from 0.7 to 1.5 m of sea level equivalent, contrasting with previous studies. Our results suggest an important contribution of the Antarctic ice sheet to the LIG highstand.

scholarly journals Asynchronous Antarctic and Greenland ice-volume contributions to the last interglacial sea-level highstand

2020 ◽  
Author(s):  
Eelco Rohling ◽  
Fiona Hibbert
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Global Climate ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Climate Forcing ◽  
Potential Contribution ◽  
Last Interglacial ◽  
Ice Shelf

<p>Sea-level rise is among the greatest risks that arise from anthropogenic global climate change. It is receiving a lot of attention, among others in the IPCC reports, but major questions remain as to the potential contribution from the great continental ice sheets. In recent years, some modelling work has suggested that the ice-component of sea-level rise may be much faster than previously thought, but the rapidity of rise seen in these results depends on inclusion of scientifically debated mechanisms of ice-shelf decay and associated ice-sheet instability. The processes have not been active during historical times, so data are needed from previous warm periods to evaluate whether the suggested rates of sea-level rise are supported by observations or not. Also, we then need to assess which of the ice sheets was most sensitive, and why. The last interglacial (LIG; ~130,000 to ~118,000 years ago, ka) was the last time global sea level rose well above its present level, reaching a highstand of +6 to +9 m or more. Because Greenland Ice Sheet (GrIS) contributions were smaller than that, this implies substantial Antarctic Ice Sheet (AIS) contributions. However, this still leaves the timings, magnitudes, and drivers of GrIS and AIS reductions open to debate. I will discuss recently published sea-level reconstructions for the LIG highstand, which reveal that AIS and GrIS contributions were distinctly asynchronous, and that rates of rise to values above 0 m (present-day sea level) reached up to 3.5 m per century. Such high pre-anthropogenic rates of sea-level rise lend credibility to high rates inferred by ice modelling under certain ice-shelf instability parameterisations, for both the past and future. Climate forcing was distinctly asynchronous between the southern and northern hemispheres as well during the LIG, explaining the asynchronous sea-level contributions from AIS and GrIS. Today, climate forcing is synchronous between the two hemispheres, and also faster and greater than during the LIG. Therefore, LIG rates of sea-level rise should likely be considered minimum estimates for the future.</p>

scholarly journals Melting of Northern Greenland during the last interglacial

2011 ◽  
Vol 5 (6) ◽  
pp. 3517-3539 ◽  
Author(s):  
A. Born ◽  
K. H. Nisancioglu
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Last Interglacial ◽  
The South ◽  
High Accumulation ◽  
Positive Feedbacks ◽  
Geological Past

Abstract. The Greenland ice sheet (GrIS) is losing mass at an increasing rate, making it the primary contributor to global eustatic sea level rise. Large melting areas and rapid thinning at its margins has raised concerns about its stability. However, it is conceivable that these observations represent the transient adjustment of the fastest reacting parts of the ice sheet, masking slower processes that dominate the long term fate of the GrIS and its contribution to sea level rise. Studies of the geological past provide valuable information on the long term response of the GrIS to warm periods. We simulate the GrIS during the Eemian interglacial, a period 126 000 yr before present (126 ka) with Arctic temperatures comparable to projections for the end of this century. The northeastern part of the GrIS is unstable and retreats significantly, despite moderate melt rates. Unlike the south and west, strong melting in the northeast is not compensated by high accumulation, or fast ice flow. The analogy with the present warming suggests that in coming decades, positive feedbacks could increase the rate of mass loss of the northeastern GrIS, exceeding the currently observed melting in the south.

scholarly journals The future sea-level contribution of the Greenland ice sheet: a multi-model ensemble study of ISMIP6

2020 ◽  
Author(s):  
Heiko Goelzer ◽  
Sophie Nowicki ◽  
Anthony Payne ◽  
Eric Larour ◽  
Helene Seroussi ◽  
...  
Keyword(s):  
Mass Loss ◽  
Sea Level Rise ◽  
Sea Level ◽  
Model Uncertainty ◽  
Climate Model ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Global Climate Models ◽  
Climate Forcing ◽  
The Arctic

Abstract. The Greenland ice sheet is one of the largest contributors to global-mean sea-level rise today and is expected to continue to lose mass as the Arctic continues to warm. The two predominant mass loss mechanisms are increased surface meltwater runoff and mass loss associated with the retreat of marine-terminating outlet glaciers. In this paper we use a large ensemble of Greenland ice sheet models forced by output from a representative subset of CMIP5 global climate models to project ice sheet changes and sea-level rise contributions over the 21st century. The simulations are part of the Ice Sheet Model Intercomparison Project for CMIP6 (ISMIP6). We estimate the sea-level contribution together with uncertainties due to future climate forcing, ice sheet model formulations and ocean forcing for the two greenhouse gas concentration scenarios RCP8.5 and RCP2.6. The results indicate that the Greenland ice sheet will continue to lose mass in both scenarios until 2100 with contributions of 89 ± 51 mm and 31 ± 16 mm to sea-level rise for RCP8.5 and RCP2.6, respectively. The largest mass loss is expected from the southwest of Greenland, which is governed by surface mass balance changes, continuing what is already observed today. Because the contributions are calculated against a unforced control experiment, these numbers do not include any committed mass loss, i.e. mass loss that would occur over the coming century if the climate forcing remained constant. Under RCP8.5 forcing, ice sheet model uncertainty explains an ensemble spread of 40 mm, while climate model uncertainty and ocean forcing uncertainty account for a spread of 36 mm and 19 mm, respectively. Apart from those formally derived uncertainty ranges, the largest gap in our knowledge is about the physical understanding and implementation of the calving process, i.e. the interaction of the ice sheet with the ocean.

scholarly journals The future sea-level contribution of the Greenland ice sheet: a multi-model ensemble study of ISMIP6

2020 ◽  
Vol 14 (9) ◽  
pp. 3071-3096 ◽  
Author(s):  
Heiko Goelzer ◽  
Sophie Nowicki ◽  
Anthony Payne ◽  
Eric Larour ◽  
Helene Seroussi ◽  
...  
Keyword(s):  
Mass Loss ◽  
Sea Level Rise ◽  
Sea Level ◽  
Model Uncertainty ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Climate Forcing ◽  
The Arctic ◽  
Model Intercomparison ◽  
Intercomparison Project

Abstract. The Greenland ice sheet is one of the largest contributors to global mean sea-level rise today and is expected to continue to lose mass as the Arctic continues to warm. The two predominant mass loss mechanisms are increased surface meltwater run-off and mass loss associated with the retreat of marine-terminating outlet glaciers. In this paper we use a large ensemble of Greenland ice sheet models forced by output from a representative subset of the Coupled Model Intercomparison Project (CMIP5) global climate models to project ice sheet changes and sea-level rise contributions over the 21st century. The simulations are part of the Ice Sheet Model Intercomparison Project for CMIP6 (ISMIP6). We estimate the sea-level contribution together with uncertainties due to future climate forcing, ice sheet model formulations and ocean forcing for the two greenhouse gas concentration scenarios RCP8.5 and RCP2.6. The results indicate that the Greenland ice sheet will continue to lose mass in both scenarios until 2100, with contributions of 90±50 and 32±17 mm to sea-level rise for RCP8.5 and RCP2.6, respectively. The largest mass loss is expected from the south-west of Greenland, which is governed by surface mass balance changes, continuing what is already observed today. Because the contributions are calculated against an unforced control experiment, these numbers do not include any committed mass loss, i.e. mass loss that would occur over the coming century if the climate forcing remained constant. Under RCP8.5 forcing, ice sheet model uncertainty explains an ensemble spread of 40 mm, while climate model uncertainty and ocean forcing uncertainty account for a spread of 36 and 19 mm, respectively. Apart from those formally derived uncertainty ranges, the largest gap in our knowledge is about the physical understanding and implementation of the calving process, i.e. the interaction of the ice sheet with the ocean.

scholarly journals Coupled regional climate–ice-sheet simulation shows limited Greenland ice loss during the Eemian

2013 ◽  
Vol 9 (4) ◽  
pp. 1773-1788 ◽  
Author(s):  
M. M. Helsen ◽  
W. J. van de Berg ◽  
R. S. W. van de Wal ◽  
M. R. van den Broeke ◽  
J. Oerlemans
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Regional Climate ◽  
Ice Core ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Interglacial Period ◽  
Temperature Record ◽  
Last Interglacial ◽  
Central Dome

Abstract. During the last interglacial period (Eemian, 130–115 kyr BP) eustatic global sea level likely peaked at > 6 m above the present-day level, but estimates of the contribution of the Greenland Ice Sheet vary widely. Here we use an asynchronously two-way-coupled regional climate–ice-sheet model, which includes physically realistic feedbacks between the changing ice sheet topography and climate forcing. Our simulation results in a contribution from the Greenland Ice Sheet to the Eemian sea level highstand between 1.2 and 3.5 m, with a most likely value of 2.1 m. Simulated Eemian ice loss in Greenland is dominated by the rapid retreat of the southwestern margin; two-thirds of the ice loss occurred south of 70° N. The southern dome survived the Eemian and remained connected to the central dome. Large-scale ice sheet retreat is prevented in areas with high accumulation. Our results broadly agree with ice-core-inferred elevation changes and marine records, but it does not match with the ice-core-derived temperature record from northern Greenland. During maximum Eemian summertime insolation, Greenland mass loss contributed ~ 0.5 m kyr−1 to sea level rise, 24% of the reconstructed total rate of sea level rise. Next to that, a difference of > 3 m remains between our maximum estimate of the Greenland contribution and the reconstructed minimum value of the global eustatic Eemian highstand. Hence, the Antarctic Ice Sheet must also have contributed significantly to this sea level highstand.

scholarly journals Sea-level trends across The Bahamas constrain peak last interglacial ice melt

2021 ◽  
Vol 118 (33) ◽  
pp. e2026839118
Author(s):  
Blake Dyer ◽  
Jacqueline Austermann ◽  
William J. D’Andrea ◽  
Roger C. Creel ◽  
Michael R. Sandstrom ◽  
...  
Keyword(s):  
Sea Level ◽  
Age Determination ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Last Interglacial ◽  
The Bahamas ◽  
West Antarctic Ice Sheet ◽  
Ice Melt ◽  
West Antarctic ◽  
Level Data

During the last interglacial (LIG) period, global mean sea level (GMSL) was higher than at present, likely driven by greater high-latitude insolation. Past sea-level estimates require elevation measurements and age determination of marine sediments that formed at or near sea level, and those elevations must be corrected for glacial isostatic adjustment (GIA). However, this GIA correction is subject to uncertainties in the GIA model inputs, namely, Earth’s rheology and past ice history, which reduces precision and accuracy in estimates of past GMSL. To better constrain the GIA process, we compare our data and existing LIG sea-level data across the Bahamian archipelago with a suite of 576 GIA model predictions. We calculated weights for each GIA model based on how well the model fits spatial trends in the regional sea-level data and then used the weighted GIA corrections to revise estimates of GMSL during the LIG. During the LIG, we find a 95% probability that global sea level peaked at least 1.2 m higher than today, and it is very unlikely (5% probability) to have exceeded 5.3 m. Estimates increase by up to 30% (decrease by up to 20%) for portions of melt that originate from the Greenland ice sheet (West Antarctic ice sheet). Altogether, this work suggests that LIG GMSL may be lower than previously assumed.

scholarly journals Contribution of Greenland ice sheet melting to sea level rise during the last interglacial period: an approach combining ice sheet modelling and proxy data

2012 ◽  
Vol 8 (4) ◽  
pp. 3345-3377
Author(s):  
A. Quiquet ◽  
C. Ritz ◽  
H. J. Punge ◽  
D. Salas y Mélia
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Interglacial Period ◽  
Last Interglacial ◽  
Proxy Data ◽  
Intergovernmental Panel ◽  
Period Range ◽  
Ice Sheet Modelling

Abstract. In the context of global warming, the contribution of the two major ice sheets, Antarctica and Greenland, to global sea level rise is a subject of key importance for the scientific community (4th assessment report of the Intergovernmental Panel on climate change, IPCC-AR4, Meehl et al., 2007). By the end of the next century, a 3–5 °C warm up is expected in Greenland. Similar temperatures in this region were reached during the last interglacial (LIG) period due to a change in orbital configuration rather than to anthropogenic forcing. Ice core evidence suggests that the Greenland Ice Sheet (GIS) has survived this warm period but great uncertainties remain about the total Greenland ice reduction during the LIG and its sea level rise contribution. In order to improve our confidence in future state projections, we first intend to reconstruct the past states of the GIS using ice sheet modelling, and confront the simulations with paleo data. The chosen methodoly of paleoclimate reconstruction is strongly based on proxy data. Proxy data are also used to constrain the ice sheet model during the calibration phase. Our estimates of Greenland melting contribution to sea level rise during the LIG period range from 0.65 to 1.5 m of sea level equivalent.

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