A large portion of the glacial mass in Antarctic, previously thought to be relatively stable, is now understood to be destablizing. This is new research just out in Science. The abstract is pretty clear:
Growing evidence has demonstrated the importance of ice shelf buttressing on the inland grounded ice, especially if it is resting on bedrock below sea level. Much of the Southern Antarctic Peninsula satisfies this condition and also possesses a bed slope that deepens inland. Such ice sheet geometry is potentially unstable. We use satellite altimetry and gravity observations to show that a major portion of the region has, since 2009, destabilized. Ice mass loss of the marine-terminating glaciers has rapidly accelerated from close to balance in the 2000s to a sustained rate of –56 ± 8 gigatons per year, constituting a major fraction of Antarctica’s contribution to rising sea level. The widespread, simultaneous nature of the acceleration, in the absence of a persistent atmospheric forcing, points to an oceanic driving mechanism.
The paper is "Dynamic thinning of glaciers on the Southern Antarctic Peninsula" by B. Wouters, A. Martin-Español, V. Helm, T. Flament, J. M. van Wessem, S. R. M. Ligtenberg, M. R. van den Broeke, J. L. Bamber.
Here is a simulation of grounding line retreat in action from NASA:
Karl Mathiesen at the Guardian has a writeup on the research here.
The sheet’s thickness has remained stable since satellite observations began in 1992. But Professor Jonathan Bamber of Bristol university, who co-authored the study, said that around 2009 it very suddenly began to thin by an average of 42cm each year. Some areas had fallen by up to 4m.
“It hasn’t been going up, it hasn’t been going down – until 2009. Then it just seemed to pass some kind of critical threshold and went over a cliff and it’s been losing mass at a pretty much constant, rather large, rate,” said Bamber.
The estimate of ice loss by this research might be overestimated, according to Andrew Shepherd, who notes that some of the thinning of the glacier could be due to changes in snowfall amounts on tip, rather than melting from the bottom. It will be interesting to see how this works out.
Caption for the figure at the top of the post:
Fig. 2 Mass variations for the sum of basins 23 and 24, as observed by GRACE and modeled by RACMO2.3.
Basins 23 and 24 are defined in (21, 22). The faint blue dots are the monthly GRACE anomalies with 1σ error bars (20), and the thick blue line shows the anomalies with a 7-month running average applied so as to reduce noise. Cumulative SMB anomalies from RACMO2.3 are shown in red, with the light red area indicating the 1σ spread in an ensemble obtained by varying the baseline period (20). The dashed light blue line shows the estimated dynamic mass loss (GRACE minus SMB). The vertical dashed lines indicate January 2003, December 2009, and July 2010, the start and ending of the different altimetry observations. (Inset) The GRACE time series for the individual basins 23 (blue) and 24 (red), before (full lines) and after (dashed lines) applying the SMB correction.
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Greg,
This specific paper is with regards to the "Southern Antarctic Peninsula" you do understand that that PART of Antarctica is NOT the entire continent of Antarctica?
Anyone, including myself reading your title:
"New Research: Antarctic Glaciers Destabilized"
might, just might, think that ALL of Antarctica's glaciers (meaning the entire ice sheet (WAIS/EAIS)) have become destabilized.
Just, you know, sayin'
They are glaciers. They are in the Antarctic. They are destabilized.
"Americans Killed In Iraq Bomb Attack" ... all of the Americans?
"Deer Killed By Semi On Route 9" all of the deer?
This is not a thing.
Just came across this headline:
"Syria crisis: 'Children died' in US air strike"
All of the children have died! OMG!
So now the 'skeptics' are reduced to quibbling about headlines.
Next will be your alarmist punctuation and grammar.
No, they'll pick up on the conspiracy evident by Greg's misspellings. It obviously indicates a state of cognitive dissonance due to lying about AGW. Nervous fingers hit the wrong keys... (You heard it here first!)
Thanks for posting this Greg, but with all due respect, the NASA vid you posted isn't the best. It's missing the "woo" effect (per Richard Alley) that demonstrates why marine based ice sheets on bed slopes that deepen inland are so dangerous. This is from a lecture he did at Stanford in 2012, The whole thing is interesting, but I cued it up to the "woo" effect.. Maybe you would like to post it?
https://www.youtube.com/watch?v=o4oMsfa_30Q#t=37m15s
Greg, I'm having trouble posting & hope this isn't a duplicate. I cued this up to Richard Alley's description of the "woo" effect, the reason why marine-based ice sheets on bed slopes that deepen inland are so dangerous.
https://www.youtube.com/watch?v=o4oMsfa_30Q#t=37m15s
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