Rate of mass loss from the Greenland Ice Sheet will exceed Holocene values this century

Briner, Jason P.; Cuzzone, Joshua; Badgeley, J.; Young, Nicolás E.; Steig, Eric J.; Morlighem, Mathieu; Schlegel, Nicole‐Jeanne; Hakim, Gregory J.; Schaefer, Joerg M.; Johnson, Jesse V.; Lesnek, Alia J.; Thomas, Elizabeth K.; Allan, Estelle; Bennike, Ole; Cluett, A.; Csathó, Beáta; Vernal, Anne de; Downs, Jacob; Larour, Eric; Nowicki, S.

doi:10.1038/s41586-020-2742-6

Cited by 78 publications

(96 citation statements)

References 55 publications

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“…17). In particular, north of the KNS region between Sisimiut and Kangerlussuaq, the simulated pattern and timing of icemargin migration generally reproduces the geologic record of ice-margin change (Briner et al, 2020). In the KNS region, these same simulations generally depict an ice-margin that retreats eastwards, achieves a minimum extent, and then readvances in the late Holocene, thus sharing the broad outline of GrIS change provided by the available geological observations (Fig.…”

Section: Geologic Data-model Comparison Of Ice-margin Change In Southsupporting

confidence: 67%

“…We utilize recent paleo-simulations of southwestern GrIS change using the high-resolution Ice Sheet and Sea-level System Model (ISSM; Larour et al, 2012;Cuzzone et al, 2018Cuzzone et al, , 2019Briner et al, 2020). The model set-up has been previously described in Cuzzone et al (2019) and Briner et al (2020), but here we briefly describe model attributes. The model domain extends from the present-day coastline to the GrIS divide.…”

Section: Ice-sheet Model Simulations Of Southwestern Gris Changementioning

confidence: 99%

“…Geologic reconstructions of ice-sheet change offer an ideal target for ice-sheet modeling efforts aimed at reconstructing the geometry and ice volume of past ice sheets through model tuning (Simpson et al, 2009;Lecavalier et al, 2014). These reconstructions, however, also serve as an ideal testbed for modeling efforts aimed at evaluating the sensitivity of past ice-margin migration to climatic and oceanic influences (Briner et al, 2020). Paleo ice-sheet modeling efforts typically rely on coarse resolution meshes and simplification of ice-flow approximations to achieve computational efficiency.…”

Section: Geologic Data-model Comparison Of Ice-margin Change In Southmentioning

confidence: 99%

“…While this approach has enabled more simple models to assess the sensitivity of ice-margin response to model parameters, crude climate forcings are typically used, making it difficult to properly assess ice-margin sensitivity to climate. Here, we further explore the deglaciation history of the KNS region by comparing the geologic record of ice-sheet change to recently completed model simulations of southwestern GrIS evolution through the Holocene (Cuzzone et al, 2019;Briner et al, 2020). These https://doi.org/10.5194/cp-2020-111 Preprint.…”

Section: Geologic Data-model Comparison Of Ice-margin Change In Southmentioning

confidence: 99%

“…Holocene ice model simulations use the highest horizontal mesh resolution across our field area to date, and use a range of state-of-the-science gridded climate reconstructions as the input climate (Badgeley et al, 2020;Briner et al, 2020), thus presenting an opportunity for new insights regarding glacier history and ice-sheet modeling. Our goals in exploring the model simulations are to (a) assess the magnitude of recession inboard of the present margin, (b) compare rates of retreat and timing of ice-margin change in both the model and in the observations, and (c) explore avenues for model improvement in a known problem area for ice-sheet modeling.…”

Section: Geologic Data-model Comparison Of Ice-margin Change In Southmentioning

confidence: 99%

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Cosmogenic isotope measurements from recently deglaciated bedrock as a new tool to decipher changes in Greenland Ice Sheet size

Young

Lesnek

Cuzzone

et al. 2020

Preprint

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Abstract. During the middle to late Holocene (8.2 ka BP to present), the Greenland Ice Sheet (GrIS) was smaller than its current configuration. Determining the exact dimensions of the Holocene ice-sheet minimum and the duration that the ice margin rested inboard of its current position remains challenging. Contemporary retreat of the GrIS from its historical maximum extent in southwestern Greenland is exposing a landscape that holds clues regarding the configuration and timing of past ice-sheet minima. To quantify the duration of the time the GrIS margin was near its modern extent we develop a new technique on Greenland that utilizes in situ cosmogenic 10Be-14C-26Al in bedrock samples that have become ice free only in the last few decades by the retreating ice-sheet margin at Kangiata Nunaata Sermia (n = 12 sites; KNS), southwest Greenland. To maximize the utility of this approach, we refine the deglaciation history of the region with stand-alone 10Be measurements (n = 49) and traditional 14C ages from sedimentary deposits contained in proglacial-threshold lakes. We combine our reconstructed ice-margin history in the KNS region with additional geologic records from southwestern Greenland and recent model simulations of GrIS change, to constrain the timing of the GrIS minimum in southwest Greenland, the magnitude of Holocene inland GrIS retreat, and explore the regional climate history influencing Holocene ice-sheet behavior. Our 10Be-14C-26Al measurements reveal that 1) KNS retreated behind its modern margin just before 10 ka, but likely stabilized near the present GrIS margin for several thousand years before retreating farther inland, and 2) pre-Holocene 10Be detected in several of our sample sites is most easily explained by several thousand years of surface exposure during the Last Interglaciation. Moreover, our new results indicate that the minimum extent of the GrIS likely occurred after ~ 5 ka, and the GrIS margin may have approached its eventual historical maximum extent as early as ~ 2 ka. Recent simulations of GrIS change are able to match the geologic record of ice-sheet change in regions dominated by surface mass balance, but produce a poorer model-data fit in areas influenced by oceanic and dynamic processes. Simulations that achieve the best model-data fit suggest that inland retreat of the ice margin driven by early to middle Holocene warmth may have been mitigated by increased precipitation. Triple 10Be-14C-26Al measurements in recently deglaciated bedrock provide a new tool to help decipher the duration of smaller-than-present ice over multiple timescales. Modern retreat of the GrIS margin in southwest Greenland is revealing a bedrock landscape that was also exposed during the migration of the GrIS margin towards its Holocene minimum extent, but has yet to tap into a landscape that remained ice covered throughout the entire Holocene.

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Section: Geologic Data-model Comparison Of Ice-margin Change In Southsupporting

confidence: 67%

Section: Ice-sheet Model Simulations Of Southwestern Gris Changementioning

confidence: 99%

Section: Geologic Data-model Comparison Of Ice-margin Change In Southmentioning

confidence: 99%

Section: Geologic Data-model Comparison Of Ice-margin Change In Southmentioning

confidence: 99%

Section: Geologic Data-model Comparison Of Ice-margin Change In Southmentioning

confidence: 99%

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Cosmogenic isotope measurements from recently deglaciated bedrock as a new tool to decipher changes in Greenland Ice Sheet size

Young

Lesnek

Cuzzone

et al. 2020

Preprint

Self Cite

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The Natural Environment and Its Biodiversity in Greenland During the Present Climate Change

Johnsen

Heide-Jørgensen

2021

Biogeography in the Sub‐Arctic

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Climatic control on the retreat of the Laurentide Ice Sheet margin in easternmost Québec–Labrador (Canada) revealed by cosmogenic nuclide exposure dating

Couette

Ghienne

Lajeunesse

et al. 2023

J Quaternary Science

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The Laurentide Ice Sheet (LIS) was the largest ice sheet in the Northern Hemisphere during the last glacial cycle. The effects of its demise on global climate and sea‐level changes during the subsequent deglaciation are unequivocal. Understanding the interplay between ice sheets and long‐term or short‐term (e.g. abrupt) climatic events is therefore crucial for predicting future rates of ice sheet melting and their potential contribution to sea‐level changes. Here, we present 37 new 10Be surface exposure ages from easternmost Québec–Labrador that allow us to identify close ties between regional deglaciation history and climate. These results reveal that the LIS was disconnected from the Newfoundland Ice Cap by ~14.1 ka. Samples collected from moraine boulders indicate that this event was followed by five major stillstands and/or readvance stages of the LIS margin. Integrating our new moraine ages with those of earlier studies allows us to depict a temporal framework including events at ~12.9, ~11.5, ~10.4, ~9.3 and ~8.4–8.2 ka. These moraine ages highlight a strong sensitivity of the LIS to temperature changes in the Northern Hemisphere, as the documented continental ice margin stabilizations coincide with abrupt cooling events recorded in Greenland ice cores. These observations support the idea of a negative feedback mechanism induced by meltwater forcings into the North Atlantic Ocean which, in turn, provoked repeated cold reversals during the Younger Dryas and early Holocene.

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Rate of mass loss from the Greenland Ice Sheet will exceed Holocene values this century

Cited by 78 publications

References 55 publications

Cosmogenic isotope measurements from recently deglaciated bedrock as a new tool to decipher changes in Greenland Ice Sheet size

Cosmogenic isotope measurements from recently deglaciated bedrock as a new tool to decipher changes in Greenland Ice Sheet size

The Natural Environment and Its Biodiversity in Greenland During the Present Climate Change

Climatic control on the retreat of the Laurentide Ice Sheet margin in easternmost Québec–Labrador (Canada) revealed by cosmogenic nuclide exposure dating

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