History of the Greenland Ice Sheet: paleoclimatic insights

Alley, Richard B.; Andrews, John T.; Brigham‐Grette, Julie; Clarke, Garry K. C.; Cuffey, Kurt M.; Fitzpatrick, Joan J.; Funder, Svend; Marshall, Shawn J.; Miller, Gifford H.; Mitrovica, J. X.; Muhs, Daniel R.; Otto‐Bliesner, Bette L.; Polyak, Leonid; White, James W. C.

doi:10.1016/j.quascirev.2010.02.007

Cited by 186 publications

(181 citation statements)

References 258 publications

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“…Unfortunately, there are no deep ice cores in northeastern Greenland. However, there are widespread marine deposits in this area from the last interglacial period, particularly during the period of peak warmth (∼ 123 ka;Funder, 1989;Mangerud and Funder, 1994;Alley et al, 2010). This indicates that seawater was present far inland following the penultimate glacial period, consistent with our model results.…”

Section: Discussionsupporting

confidence: 87%

“…In southeastern Greenland, at the Dye-3 core site, basal ice is also found to predate the Eemian (Willerslev et al, 2007). However, due to its very old age (>400 000 yr) and the lack of direct evidence of Eemian ice, an Eemian glaciation at this site remains uncertain (Alley et al, 2010). A recent study concluded moderate melting of the southern GrIS, supporting the persistence of the southern dome and probably Dye-3 (Colville et al, 2011).…”

Section: A Born and K H Nisancioglu: Melting Of Northern Greenlandmentioning

confidence: 83%

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Melting of Northern Greenland during the last interglaciation

Born

Nisancioglu

2012

The Cryosphere

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Abstract. Using simulated climate data from the comprehensive coupled climate model IPSL CM4, we simulate the Greenland ice sheet (GrIS) during the Eemian interglaciation with the three-dimensional ice sheet model SICOPOLIS. The Eemian is a period 126 000 yr before present (126 ka) with Arctic temperatures comparable to projections for the end of this century. In our simulation, the northeastern part of the GrIS is unstable and retreats significantly, despite moderate melt rates. This result is found to be robust to perturbations within a wide parameter space of key parameters of the ice sheet model, the choice of initial ice temperature, and has been reproduced with climate forcing from a second coupled climate model, the CCSM3. It is shown that the northeast GrIS is the most vulnerable. Even a small increase in melt removes many years of ice accumulation, giving a large mass imbalance and triggering the strong ice-elevation feedback. Unlike the south and west, melting in the northeast is not compensated by high accumulation. The analogy with modern warming suggests that in coming decades, positive feedbacks could increase the rate of mass loss of the northeastern GrIS, exceeding the recent observed thinning rates in the south.

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Section: Discussionsupporting

confidence: 87%

Section: A Born and K H Nisancioglu: Melting Of Northern Greenlandmentioning

confidence: 83%

Melting of Northern Greenland during the last interglaciation

Born

Nisancioglu

2012

The Cryosphere

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“…Van de Wal, 1999a;Huybrechts, 2002;Robinson et al, 2010) and paleoclimatic evidence (Fleming and Lambeck, 2004), but slightly higher than the reconstruction by Greve (2005). This low LGM ice volume is a least partly caused by the lack of ice shelf dynamics in our model, prohibiting merging of the GrIS and the Ellesmere Island section of the Laurentide Ice Sheet during the last glacial, which probably did occur in reality (England, 1999;Alley et al, 2010).…”

Section: Simulating a Full Glacial Cyclementioning

confidence: 58%

Coupling of climate models and ice sheet models by surface mass balance gradients: application to the Greenland Ice Sheet

et al. 2012

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Abstract. It is notoriously difficult to couple surface mass balance (SMB) results from climate models to the changing geometry of an ice sheet model. This problem is traditionally avoided by using only accumulation from a climate model, and parameterizing the meltwater run-off as a function of temperature, which is often related to surface elevation (H s ). In this study, we propose a new strategy to calculate SMB, to allow a direct adjustment of SMB to a change in ice sheet topography and/or a change in climate forcing. This method is based on elevational gradients in the SMB field as computed by a regional climate model. Separate linear relations are derived for ablation and accumulation, using pairs of H s and SMB within a minimum search radius. The continuously adjusting SMB forcing is consistent with climate model forcing fields, also for initially non-glaciated areas in the peripheral areas of an ice sheet. When applied to an asynchronous coupled ice sheet -climate model setup, this method circumvents traditional temperature lapse rate assumptions. Here we apply it to the Greenland Ice Sheet (GrIS). Experiments using both steady-state forcing and glacial-interglacial forcing result in realistic ice sheet reconstructions.

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“…4. There is large inter-annual variability www.the-cryosphere.net/7/599/2013/ The Cryosphere, 7, 599-614, 2013 PMM5 1961PMM5 -1990PMM5 1961PMM5 -1990PMM5 1961PMM5 -1990PMM5 1961PMM5 -1990PMM5 1996PMM5 -2008PMM5 1996PMM5 -2008PMM5 1996PMM5 -2008PMM5 1996PMM5 -2008 [ (Alley et al, 2010) in mass balance estimation based on observation (altimetry and gravimetry) over the last decade as studies are typically carried out over different periods. Relatively small differences in the study period can have significant impact on the period's mean.…”

Section: Smb Componentsmentioning

confidence: 99%

Surface mass balance model intercomparison for the Greenland ice sheet

et al. 2013

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Abstract. A number of high resolution reconstructions of the surface mass balance (SMB) of the Greenland ice sheet (GrIS) have been produced using global re-analyses data extending back to 1958. These reconstructions have been used in a variety of applications but little is known about their consistency with each other and the impact of the downscaling method on the result. Here, we compare four reconstructions for the period 1960-2008 to assess the consistency in regional, seasonal and integrated SMB components. Total SMB estimates for the GrIS are in agreement within 34 % of the four model average when a common ice sheet mask is used. When models' native land/ice/sea masks are used this spread increases to 57 %. Variation in the spread of components of SMB from their mean: runoff 42 % (29 % native masks), precipitation 20 % (24 % native masks), melt 38 % (74 % native masks), refreeze 83 % (142 % native masks) show, with the exception of refreeze, a similar level of agreement once a common mask is used. Previously noted differences in the models' estimates are partially explained by ice sheet mask differences. Regionally there is less agreement, suggesting spatially compensating errors improve the integrated estimates.Modelled SMB estimates are compared with in situ observations from the accumulation and ablation areas. Agreement is higher in the accumulation area than the ablation area suggesting relatively high uncertainty in the estimation of ablation processes. Since the mid-1990s each model estimates a decreasing annual SMB. A similar period of decreasing SMB is also estimated for the period 1960-1972. The earlier decrease is due to reduced precipitation with runoff remaining unchanged, however, the recent decrease is associated with increased precipitation, now more than compensated for by increased melt driven runoff. Additionally, in three of the four models the equilibrium line altitude has risen since the mid-1990s, reducing the accumulation area at a rate of approximately 60 000 km 2 per decade due to increased melting. Improving process representation requires further study but the use of a single accurate ice sheet mask is a logical way to reduce uncertainty among models.

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History of the Greenland Ice Sheet: paleoclimatic insights

Cited by 186 publications

References 258 publications

Melting of Northern Greenland during the last interglaciation

Melting of Northern Greenland during the last interglaciation

Coupling of climate models and ice sheet models by surface mass balance gradients: application to the Greenland Ice Sheet

Surface mass balance model intercomparison for the Greenland ice sheet

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