Esa's Cryosat mission sees Antarctic ice losses double since 2010

[RaenorShine]

Just heard this on BBC radio news ......

http://www.bbc.co.uk/news/science-environment-27465050

Antarctica is now losing about 160 billion tonnes of ice a year to the ocean - twice as much as when the continent was last surveyed.

The new assessment comes from Europe's Cryosat satellite, which has a radar instrument specifically designed to measure the shape of the ice sheet.

The melt loss from the White Continent is sufficient to push up global sea levels by around 0.43mm per year.

Scientists report the data in the journal Geophysical Research Letters.http://onlinelibrary.wiley.com/doi/10.1002/2014GL060111/abstract

Anyone getting Climate Bad News Fatigue yet? ;p

[Buddy]

Anyone getting Climate Bad News Fatigue yet? ;p

If they are.....they are going to be REALLY tired the next 100 years....

[AbruptSLR]

RaenorShine,

Thanks for the link, but I am afraid that Buddy is right, for example, when you consider that:
(1) 2010-2011 was one of the strongest recent La Nina conditions, which considerably slowed down the ice mass loss from the PIG and the Thwaites Glacier, so the Esa Cryosat report covers an atypically slow ice mass loss period; and (2) the background fluctuations (variable snowfall, bed rebound, etc) readily masked the acceleration of the ice mass loss when the loss was small; but now that the ice mass loss from the AIS has grown, this mask is now removed.

Therefore, you can expect the SLR contribution from the WAIS to grow rapidly as we are now in an El Nino year, and as we are now beginning the positive phase of the IPO/PDO cycles during which El Nino events are much more frequent (and probably more intense) than normal.

Best,
ASLR

[RaenorShine]

My note on the end was tongue in cheek and meant as a joke about the number of such studies coming out recently.  I agree it is only going to get worse.

In reality I think we are at a tipping point (well a tipping decade) where the changes we have made to the atmosphere actually start to impact our world and be noticed by all.  Things are starting to move beyond numbers, and into actual physical impacts.  The question then becomes what can we do about it (We know the answer to this one), and also is it too late?

Looking at the graphic in the BBC news article the majority of loss is in the same areas as the Glacier Study last week.  It's another pointer from actual measurements (not computer models) that things are changing.

As you've pointed out in many of your posts, the large risk isn't of a gradual increase in flow, (although that it alarming), it's in a large collapse event which has the potential to increase sea level rapidly over a short period of time.

[AbruptSLR]

To facilitate discussion on the topic that RaenorShine raised, I post the following citation, link and abstract for the original paper:

Malcolm McMillan, Andrew Shepherd, Aud Sundal, Kate Briggs, Alan Muir, Andrew Ridout, Anna Hogg and Duncan Wingham, (2014), "Increased ice losses from Antarctica detected by CryoSat-2",  Geophysical Research Letters DOI: 10.1002/2014GL060111

http://onlinelibrary.wiley.com/doi/10.1002/2014GL060111/abstract


Abstract: "We use 3 years of Cryosat-2 radar altimeter data to develop the first comprehensive assessment of Antarctic ice sheet elevation change. This new dataset provides near-continuous (96%) coverage of the entire continent, extending to within 215 kilometres of the South Pole and leading to a fivefold increase in the sampling of coastal regions where the vast majority of all ice losses occur. Between 2010 and 2013, West Antarctica, East Antarctica, and the Antarctic Peninsula changed in mass by −134 ± 27, −3 ± 36, and −23 ± 18 Gt yr−1 respectively. In West Antarctica, signals of imbalance are present in areas that were poorly surveyed by past missions, contributing additional losses that bring altimeter observations closer to estimates based on other geodetic techniques. However, the average rate of ice thinning in West Antarctica has also continued to rise, and mass losses from this sector are now 31% greater than over the period 2005–2011."

[nukefix]

What is the scientific basis for claiming that La Nina directly affects ice stream dynamics in the Amundsen sector?

[AbruptSLR]

nukefix,

I am not at my main computer to provide specific references, but in at least two different posts I provided references to scientific peer-reviewed papers that measured the warm CDW into the ASE during the last major La Nina (2010-11) that clearly showed that during La Nina's the volume of warm CDW flowing into the ASE is reduced.  The physical basis for this has is related to the effect that a La Nina has on the SAM, which in-turn effect the location of the ABSL (the Amundsen Bellinghausen Sea Low).  During La Nina the ABSL is on average moved more westward closer to 140W, while during El Nino's the ABSL is on average moved more eastward closer to about 115W.  As in the Southern Hemisphere low pressure systems rotate clockwise, so that during an El Nino the clockwise winds centered on 115W blow more warm CDW into the ASE at about 105W than on average, Similarly, when the ABSL is more westward during a La Nina less warm CDW is blown into the ASE than average (as over the course of the year the ABSL migrates back and forth from the Bellinghausen to the Amundsen Seas.

Best,
ASLR

[nukefix]

I'd be interested in seeing the study and whether they have sufficient statistics over several El Nino/La Nina events to claim causality.

[AbruptSLR]

nukefix,

The paper that I was mostly referring to is as follows:

Dutrieux P, Rydt JD, Jenkins A, Holland PR, Ha HK, Lee SH, Steig EJ, Ding Q, Abrahamsen EP, Schroder M: Strong sensitivity of Pine Island ice-shelf melting to climatic variability, Science, 343 (6167), 174-178, (2014)
http://www.sciencemag.org/content/343/6167/174

However, if you are actually interested in this topic then you might also want to review the following:

Steig EJ, Ding Q, Battisti DS, Jenkins A: Tropical forcing of circumpolar deep water inflow and outlet glacier thinning in the Amundsen Sea Embayment, West Antarctica. Annals of Glaciology, 53, 19-28 (2012).
http://www.atmos.washington.edu/~qinghua/pdf/19.pdf

Ding Q, Steig EJ, Battisti DS, Wallace JM: Influence of the tropics on the Southern Annular Mode. Journal of Climate, 25, 6330-63 (2012).
http://www.atmos.washington.edu/~qinghua/pdf/21.pdf

Bertler, N.A., Naish, T.T., Mayewski, P.A. and Barrett, P.J., (2006), "Opposing oceanic and atmospheric ENSO influences on the Ross Sea Region, Antarctica", Advances in Geosciences, 6, pp 83-88, SRef-ID: 1680-7359/adgeo/2006-6-83

Best,
ASLR

[nukefix]

Interesting, but still speculative I guess. I'd imagine that El Nino might also change the SMB. In any case it's great that Cryosat can produce such a map every year so that our understanding of these effects can improve.