Stokes, C.R., Margold, M., Clark, C.D. orcid.org/0000-0002-1021-6679 et al. (1 more author) (2016) Ice stream activity scaled to ice sheet volume during Laurentide Ice Sheet deglaciation. Nature, 530 (7590). pp. 322-326. ISSN 0028-0836
Abstract
The contribution of the Greenland and West Antarctic ice sheets to sea level has increased in recent decades, largely owing to the thinning and retreat of outlet glaciers and ice streams1, 2, 3, 4. This dynamic loss is a serious concern, with some modelling studies suggesting that the collapse of a major ice sheet could be imminent5, 6 or potentially underway7 in West Antarctica, but others predicting a more limited response8. A major problem is that observations used to initialize and calibrate models typically span only a few decades, and, at the ice-sheet scale, it is unclear how the entire drainage network of ice streams evolves over longer timescales. This represents one of the largest sources of uncertainty when predicting the contributions of ice sheets to sea-level rise8, 9, 10. A key question is whether ice streams might increase and sustain rates of mass loss over centuries or millennia, beyond those expected for a given ocean–climate forcing5, 6, 7, 8, 9, 10. Here we reconstruct the activity of 117 ice streams that operated at various times during deglaciation of the Laurentide Ice Sheet (from about 22,000 to 7,000 years ago) and show that as they activated and deactivated in different locations, their overall number decreased, they occupied a progressively smaller percentage of the ice sheet perimeter and their total discharge decreased. The underlying geology and topography clearly influenced ice stream activity, but—at the ice-sheet scale—their drainage network adjusted and was linked to changes in ice sheet volume. It is unclear whether these findings can be directly translated to modern ice sheets. However, contrary to the view that sees ice streams as unstable entities that can accelerate ice-sheet deglaciation, we conclude that ice streams exerted progressively less influence on ice sheet mass balance during the retreat of the Laurentide Ice Sheet.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2016 Nature Publishing Group. This is an author produced version of a paper subsequently published in Nature. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | Palaeoclimate; Cryospheric science; Climate-change impacts |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Social Sciences (Sheffield) > Department of Geography (Sheffield) |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 10 Aug 2016 11:15 |
Last Modified: | 05 Nov 2017 05:39 |
Published Version: | http://dx.doi.org/10.1038/nature16947 |
Status: | Published |
Publisher: | Nature Publishing Group |
Refereed: | Yes |
Identification Number: | 10.1038/nature16947 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:102275 |