Aerial Photographs Reveal Late–20th-Century Dynamic Ice Loss in Northwestern Greenland
A Picture of Disappearing Ice
Global warming is accelerating the loss of ice sheet mass by melting, sublimation, and erosion of their margins. In order to provide a better context for understanding contemporary losses, a longer record of the recent past is needed. Kjær et al. (p. 569) extend the record of thinning along the northwest margin of the Greenland Ice Sheet back to the mid-1980s, by using archived aerial photographs in conjunction with a digital elevation model and comparing their results to more recent data. Northwestern Greenland has experienced two dynamic ice loss events in the past three decades. Local ice loss appears to be caused by a combination of predictable surface processes that operate over decadal time scales and ones that involve the rapid movement of ice over periods of 3 to 5 years that exhibit strong regional differences.
Abstract
Global warming is predicted to have a profound impact on the Greenland Ice Sheet and its contribution to global sea-level rise. Recent mass loss in the northwest of Greenland has been substantial. Using aerial photographs, we produced digital elevation models and extended the time record of recent observed marginal dynamic thinning back to the mid-1980s. We reveal two independent dynamic ice loss events on the northwestern Greenland Ice Sheet margin: from 1985 to 1993 and 2005 to 2010, which were separated by limited mass changes. Our results suggest that the ice mass changes in this sector were primarily caused by short-lived dynamic ice loss events rather than changes in the surface mass balance. This finding challenges predictions about the future response of the Greenland Ice Sheet to increasing global temperatures.
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References and Notes
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Published In
Science
Volume 337 | Issue 6094
3 August 2012
3 August 2012
Copyright
Copyright © 2012, American Association for the Advancement of Science.
Submission history
Received: 15 February 2012
Accepted: 22 June 2012
Published in print: 3 August 2012
Acknowledgments
This work is a part of the RinkProject, within the Centre for GeoGenetics, funded by the Danish Research Council, grant no. 272-08-0415, and the Commission for Scientific Research in Greenland. J.L.B. and R.H. were supported by funding from the ice2sea program from the European Union 7th Framework Programme, grant number 226375. J.W. was partially supported by NASA grants NNX08AF02G and NNXI0AR66G, and by NASA’s Making Earth Science Data Records for Use in Research Environments (MEaSUREs) program. M.v.d.B. acknowledges support from Utrecht University and the Netherlands Polar Program. Finally, we extend our gratitude toward the Danish National Cadastre and Survey for facilitating the erection of AirBase: a database containing registrations of aerial photographs from Greenland and their metadata. K.H.K., S.A.K., N.K.L., and E.W. wrote the majority of the main text with significant input from all authors. All authors contributed with interpretation and discussion of results. N.J.K. completed the aerial photogrammetric and validation analyses together with L.H.T., K.H.K., L.T.J., and A.F.-J. J.W. provided the GRACE data and analyses. K.K.K. handled the Geographical Information System and database management. J.B., M.v.d.B., and R.H. provided SMB and firn density data. A.A.B., L.H.T., and N.K.L. collected ice marginal data and analyzed their long-term significance.
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- Rapid ablation zone expansion amplifies north Greenland mass loss, Science Advances, 5, 9, (2019)./doi/10.1126/sciadv.aaw0123
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