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Runaway ice loss in Antarctica

Date:
November 30, 2015
Source:
Victoria University of Wellington
Summary:
By studying rocks at different elevations beside the East Antarctic Ice Sheet, scientists have concluded that a period of rapid glacier thinning occurred in the recent geological past, and persisted for several centuries.
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Aerial view of Mackay Glacier, which drains part of the massive East Antarctic Ice Sheet into the Ross Sea. The colours highlight the speed of ice flow; blue marks areas of slow flow, while red areas are fast flowing.
Credit: Image courtesy of Victoria University of Wellington

By studying rocks at different elevations beside the East Antarctic Ice Sheet (EAIS), a New Zealand-led team concluded that a period of rapid glacier thinning occurred in the recent geological past, and persisted for several centuries.

Satellite observations show that parts of the Antarctic ice sheet are currently thinning in response to a warming ocean. Of particular concern is the potential for 'marine ice sheet instability', where an initial retreat of ice margins into deepening valleys could lead to continued, unstable ice loss.

The new research, led by Postdoctoral Research Fellow Dr Richard Jones, indicates that the processes leading to instability can be initiated by just minor climate warming.

"The finding is very important for predicting Antarctica's future contribution to sea level change," says Dr Jones. "Particularly when considering that the EAIS contains enough vulnerable ice to raise sea level by tens of metres.

"It might only require a small amount of climate variation to initiate runaway ice loss, and it could continue for centuries to millennia."

While this process has been posited for many years, the study presents the first directly recorded evidence that it has taken place in the past, providing new insight into the future behaviour of rapidly changing parts of Antarctica today.

A major strength of the study was combining numerical modelling experiments that simulate glacier retreat with geological data recording past ice surface lowering.

"Most research has previously focused on the West Antarctic Ice Sheet, which makes these observations from East Antarctica all the more significant," says Dr Jones.

The field work and data collection conducted as part of this study were captured in a video and can be viewed at https://vimeo.com/80447422.


Story Source:

Materials provided by Victoria University of Wellington. Note: Content may be edited for style and length.


Journal Reference:

  1. R. S. Jones, A. N. Mackintosh, K. P. Norton, N. R. Golledge, C. J. Fogwill, P. W. Kubik, M. Christl, S. L. Greenwood. Rapid Holocene thinning of an East Antarctic outlet glacier driven by marine ice sheet instability. Nature Communications, 2015; 6: 8910 DOI: 10.1038/ncomms9910

Cite This Page:

Victoria University of Wellington. "Runaway ice loss in Antarctica." ScienceDaily. ScienceDaily, 30 November 2015. <www.sciencedaily.com/releases/2015/11/151130084631.htm>.
Victoria University of Wellington. (2015, November 30). Runaway ice loss in Antarctica. ScienceDaily. Retrieved May 23, 2017 from www.sciencedaily.com/releases/2015/11/151130084631.htm
Victoria University of Wellington. "Runaway ice loss in Antarctica." ScienceDaily. www.sciencedaily.com/releases/2015/11/151130084631.htm (accessed May 23, 2017).

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