2010-09-12 01:51:36Basic Rebuttal #10: Antarctica is Gaining Ice
Robert Way

robert_way19@hotmail...
142.162.205.242
Skeptic arguments that Antarctica is gaining ice frequently hinge on an error of omission, namely ignoring the difference between land ice and sea ice.

In glaciology and particularly with respect to Antarctic ice, not all things are created equal. Let us consider the following differences. Antarctic land ice is the ice which has accumulated over thousands of years on the Antarctica landmass itself through snowfall. This land ice therefore is actually stored ocean water that once fell as precipitation. Sea ice in Antarctica is quite different as it is generally considered to be ice which forms in salt water primarily during the winter months.

In Antarctica, sea ice grows quite extensively during winter but nearly completely melts away during the summer (Figure 1). That is where the important difference between antarctic and arctic sea ice exists. Arctic sea ice lasts all the year round, there are increases during the winter months and decreases during the summer months but an ice cover does in fact remain in the North which includes quite a bit of ice from previous years (Figure 1). Essentially Arctic sea ice is more important for the earth's energy balance because when it melts, more sunlight is absorbed by the oceans whereas Antarctic sea ice normally melts each summer leaving the earth's energy balance largely unchanged.

Figure 1: Coverage of sea ice in both the Arctic (Top) and Antarctica (Bottom) for both summer minimums and winter maximums
Source: National Snow and Ice Data Center

One must also be careful how you interpret trends in Antarctic sea ice. Currently this ice is increasing and has been for years but is this the smoking gun against climate change? Not quite. Antarctic sea ice is gaining because of many different reasons but the most accepted recent explanations are listed below:

i) Ozone levels over Antarctica have dropped causing stratospheric cooling and increasing winds which lead to more areas of open water that can be frozen (Gillet 2003, Thompson 2002, Turner 2009).

and

ii) The Southern Ocean is freshening because of increased rain, glacial run-off and snowfall. This changes the composition of the different layers in the ocean there causing less mixing between warm and cold layers and thus less melted sea ice (Zhang 2007).

All the sea ice talk aside, it is quite clear that really when it comes to Antarctic ice, sea ice is not the most important thing to measure. In Antarctica, the most important ice mass is the land ice sitting on the West Antarctic Ice Sheet and the East Antarctic Ice Sheet.

Therefore, how is Antarctic Land-ice doing?

Figure 2: Estimates of Total Antarctic Land Ice Changes and approximate sea level contributions using many different measurement techniques. Adapted from The Copenhagen Diagnosis. (CH= Chen et al. 2006, WH= Wingham et al. 2006, R= Rignot et al. 2008b, CZ= Cazenave et al. 2009 and V=Velicogna 2009)

Estimates of recent changes in Antarctic land ice (Figure 2) range from losing 100 Gt/year to over 300 Gt/year. Because 360 Gt/year represents an annual sea level rise of 1 mm/year, recent estimates indicate a contribution of between 0.27 mm/year and 0.83 mm/year coming from Antarctica. There is of course uncertainty in the estimations methods but multiple different types of measurement techniques (explained here) all show the same thing, Antarctica is losing land ice as a whole, and these losses are accelerating quickly.
2010-09-12 05:17:22You might want to look at
nealjking

nealjking@gmail...
84.151.46.1

the argument for #104.

There seems to be some overlap of material here, that should perhaps be rationalized in some way.

2010-09-12 05:55:53nice job
dana1981
Dana Nuccitelli
dana1981@yahoo...
71.137.148.215

I think it looks good.  In response to neal, I'm not sure how you avoid overlap between 'southern sea ice is increasing' and 'Antarctica is gaining ice'.  They're very similar arguments, so I don't see a problem with overlap in the rebuttals.

A couple of minor comments.  I suppose it probably is fortunate that all things are not created equal, but the start of the second paragraph is still a little odd.  I would change "Fortunately" to "However".

Toward the end, another paragraph begins "All the sea ice talk aside, it is quite clear that really when it comes to Antarctic ice, not all ice is as important as one another."

This is rather awkward, and I would change the end to read "not all types of ice are equally important."

Generally speaking I think this might be pushing the boundary between basic and intermediate, but I still think it's good.

2010-09-12 10:12:10Comment
Robert Way

robert_way19@hotmail...
142.162.205.242
I'll revise it a little, I kinda just threw it together but I agree that it is pushing the boundary... It is a hard topic to deal with because of its overlap and complexity... Any suggestions about how to lower the level?
2010-09-12 15:38:43Some suggestions
gpwayne
Graham Wayne
graham@gpwayne...
86.158.204.104

Hi Robert - I've addressed this argument many times (I study the cryrosphere a little more than other aspects of climate change), so I may be able to help. Here are some suggestions:

"The basis for the any skeptic argument that Antarctica is gaining ice hinges on the hopes that their readers will not understand the difference between land ice and sea ice. Another thing that is hoped is that Antarctic sea ice will be given the same importance as perennial Arctic sea ice. "

It seems to me you don't spend enough time hanging out with deniers - you lucky chap! I say this because the way you've framed the arguments isn't how it is put in the MSM (the Guardian and WUWT are my principle sources). Leaving aside Arctic arguments (I've never seen that issue raised), the Antarctic scepticism does not usually conflate land and sea ice. Not only that, but they actually have a genuine question to ask and we must be careful we don't appear to duck it.

There are two arguments on offer (broadly). The first is that sea ice is growing. This is the genuine question, because it is indeed growing in the southern ocean. To sceptics - to me actually - this is rather counter-intuitive. The obvious argument they make - eschewing the science as they usually do - is that if the world is getting warmer, how come there is more sea ice. Your first challenge is to explain how the higher temperatures promote sea ice formation. This could also cover the ozone hole issue and its effect on the unique Antarctic microclimate, two points I don't think you really address.

The other half of the argument concerns the ice cap. Here, claims are straightforward and wrong - that the ice cap is gaining mass (even though this was predicted through increased precipitation, it isn't happening). Our knowledge came in stages - we knew the WAIS was losing mass but the EAIS was thought to be gaining. We now believe this isn't the case, but that both are experience negative mass balance. (Eric Rignot is good on this, but you do need to account for the Wu findings regarding isostatic rebound, since the GPS corrections apply here as well as in your Greenland piece)

So - there are some suggestions about a different way of coming at this. As I finished the last para, it seemed you could also say I'd written a reasonable basic version by accident (after cutting out the sarcastic comments). Use what you can.

(PS - that graph is really scary. Not basic at all). 

2010-09-13 15:48:13Comment
Robert Way

robert_way19@hotmail...
142.162.13.137
Graham,

My thinking is the new estimate from Bamber and Riva 2010 which uses Rignot`s (2008 a and b) estimates as long as Hock et al. (2008 or 2009) estimates to make their Antarctic assessment is likely the best. I have not ever been a big fan of Grace for Antarctica and the fact that a very well renowned glaciologist like Jonathan Bamber is using Rignot`s for Antartica and Grace for most anything else is in fact good enough for me on this subject. Wu et al (2010) estimate of 60 GT of loss from the WAIS must have some serious issues with it in my opinion. That being said, for Greenland it is not terribly far off other prominent estimates and with the GPS stations around Greenland I think maybe it is more accurate there. I would actually not be shocked if Antarctic losses are actually greater than in Greenland.

I think with respect to the EAIS it is clear that even Wu`s findings show it is losing ice and that was really the only thing keeping it from being unequivocal. Overall it is a hard thing to judge but going forward I might just use a different graph from maybe Rignot`s or Bamber and cite Bambers results since he chose not to use Grace for a reason im assuming. Myself personally I like the radar interferometry mass flux sort of method but then again i`m biased as that is one of the types of remote sensing i like. Either way, I agree with some of your commentary pertaining to the article and will try to address it. Ultimately where I struggle is how to replace the complicated graphic with something easier. I dont think Rignot or Bamber actually have a very good figure for this so that would leave me with Grace, which is something im leaning away from using until this Wu et al. stuff is dealt with and understood whether it is right or not for Antarctica.

In terms of the Sea ice arguments, I did deal with the ozone one. but not the warming one. I dont know if I should or not because it might open a can of worms with the whole is antarctica warming question...

I actually do find land and sea ice get mixed up a lot and people repeatedly refer to global ice as being stable and then show a graph of sea ice globally...
2010-09-13 19:00:47The graph
nealjking

nealjking@gmail...
91.33.124.246

I think the graph is a bit daunting.

If you really think it's useful, please spell out what the message is from it. In technical articles generally, I hate it when someone says, "The results are shown in Figure 5.2," and then just moves on. As the non-expert reader, I don't know what I'm looking for, so I don't know what conclusion the author thinks is so obvious.  Walk through it, tell me what it means.

2010-09-13 19:05:01Tone
nealjking

nealjking@gmail...
91.33.124.246

"The basis for the any skeptic argument that Antarctica is gaining ice hinges on the hopes that their readers will not understand the difference between land ice and sea ice. Another thing that is hoped is that Antarctic sea ice will be given the same importance as perennial Arctic sea ice. "

Not a good idea to write under the assumption that the other side is arguing in bad faith: It makes it appear that your primary motivation is political and not technical. Stick to the high road.

2010-09-13 23:58:36Comment
Robert Way

robert_way19@hotmail...
142.162.13.137
I would disagree slightly with your last point. If someone is making the argument that Antarctica is gaining ice then it is either ignorance or bad faith and likely the second part. We have had at least 8 years of definitive showing that ice losses are occurring ... I don't think i've ever seen someone claim that antarctica was gaining ice without it being in bad faith in all honesty (and i've seen this claim quite a bit). I've never had an argument or discussion where someone says oh really I didn't know it was losing ice... Not trying to generalize but it is my experience that if the claim is being made that Antarctica is gaining ice in 2010, that it likely originated from a Goddard-esque type mouthpiece...

I really do agree with your assessment about the graph though, this one is much more complicated than the Greenland one but I don't know what graph to use because the only ones that give nice and clear graphs in their papers is the GRACE studies and they are not something i'm willing to use for Antarctica at this point because of issues arising from Wu et al. 2010 and Bamber and Riva 2010...

We shall see if I can find something a little more user friendly though..
2010-09-14 00:16:08We are writing not just against the antagonist but also for the passers by
nealjking

nealjking@gmail...
91.33.124.246

We are not just debating, but trying to convince. Usually we will not be able to convince the direct opponent; but if we do a good job at presenting the logic and also at appearing to be the reasonable party, every once in awhile we will convince someone who is honestly in doubt.

Please check the article that John highlighted on the Authors' page, for "required reading". We are not writing just to let off steam: We are trying to change minds. Letting Goddard types dominate our awareness does not help.

2010-09-14 00:19:51Comment
Robert Way

robert_way19@hotmail...
142.162.13.137
I have tried to do some revisions. let me know what you think.
2010-09-14 00:33:40
nealjking

nealjking@gmail...
91.33.124.246

Please look at:

http://www.skepticalscience.com/thread.php?t=170

and reconsider:

"The basis for the any skeptic argument that Antarctica is gaining ice hinges on the hopes that they can confuse their readers by not mentioning the difference between land ice and sea ice"


2010-09-14 21:20:38
Rob Painting
Rob
paintingskeri@vodafone.co...
118.93.208.120

Rob, we know the skeptics are arguing in bad faith, but you'll just turn off uninformed readers if you let your anger/frustration creep into your writing.

Can we just deal with the land ice issue here & provide a link to the sea ice rebuttal?. An easier to understand graph would be good too.  

Maybe the basic version could deal with the various measurement methods in a brief overview?. Whether you choose to address the GRACE estimates or not, you can guarantee one of the first skeptic arguments will be exactly that.

Oh. and keep up the good work, I for one, appreciate the work you guys and gals are putting in.  

 

  

 

2010-09-15 03:05:45
doug_bostrom

dbostrom@clearwire...
184.77.83.151

I agree w/others that the first sentence is a little too confrontational as well as too sweeping. Could be revised along the lines of:

"Skeptic arguments that Antarctica is gaining ice frequently hinge on an error of omission, namely ignoring the difference between land ice and sea ice."

Otherwise I really like this, though I'm apparently an outlier in accepting complication so take it with a grain of salt. 

Of course you do mention it but you might further emphasize or highlight  the general lack and/or stasis of perennial sea ice in the Antarctic.

2010-09-15 04:58:40comment
Robert Way

robert_way19@hotmail...
134.153.14.191
Doug,

I myself did not like the way I had worded the initial paragraph and would not have expected it to be accepted in its state that it was. But I was not going to, nor will I give 100% credibility to the argument being presented by the other side. We are not talking about climate sensitivity here or something that people who are legitimately skeptical would inquire about, we are talking about something that is

I agree with your revisions and have implemented the revision to the first sentence. I think with respect to the lack of perennial sea ice, I would like to further elaborate if I can find a way to do so after the large revisions are done. Particularly according to most people I need to simplify the issue which is fine but I would like some direction on how to do so as I cannot plot up the data for the 2nd graph as others could.

Dappledwater,

I might need some direction on how to simplify the graph. I would also like to comment that although the sea ice argument is presented elsewhere, often when people are told antarctic ice is gaining, the premise used is that sea ice is gaining, hence the bad faith in the argument. They're essentially telling that ice is gaining, just don't look at the important ice. Either way, I could link to it, but i'd like to kinda get a show of hands as to whether that is what people want or not.

Robert Way
2010-09-15 21:13:24
Rob Painting
Rob
paintingskeri@vodafone.co...
118.92.87.75

Rob,

Simplifying your graph, I can't help you with, I'm incompetent. Maybe JC?. In it's present format it's not too easily decipherable for laypeople. I just suggested focusing on the land ice, as there is a complementary argument on the sea ice & it would allow you space to deal with issues of estimating ice sheet loss. The two arguments should link to each other for the reasons you outline, two sides of the same coin, I guess you could say.

As for bad faith, how many skeptics have you run across that argue in good faith?. Me, not so many........well none actually.


 

 

2010-09-16 02:55:29
doug_bostrom

dbostrom@clearwire...
184.77.83.151

Robert, I failed to look at the map views of interannual variation of Arctic and Antarctic ice. Those perfectly address the emphasis I was thinking of.

Now if only that graph were simpler this would be a package ready to deliver. I wonder about recasting it as a stacked chart centered on zero, w/clear acknowledgment the depiction is an adaptation?

2010-09-16 03:12:54Comment
Robert Way

robert_way19@hotmail...
142.162.13.137
Doug I agree that would be a good approach, I just have not been really able to find the data. If I had the data I could easily plot it up and find some easier way to do it. I think I could take an approximation or something of the sort. You don't by any chance know of any other documents that might have a more simpler summation for a graph?
2010-09-16 03:45:30
doug_bostrom

dbostrom@clearwire...
184.77.83.151

I'm downloading the Copenhagen Diagnosis now; source data's got be somewhere at the end of a trail of cites...will let you know.

Edit: Not simple:

Figure 10. Estimates of the net mass budget of the Antarctic Ice Sheet since 1992. Dotted boxes represent estimates used by IPCC AR4 (IPCC 2007). The solid boxes are more recent estimates (CH = Chen et al. 2006; WH = Wingham et al. 2006; R = Rignot et al. 2008b; CZ = Cazenave et al. 2009; V = Velicogna 2009).

First thing that occurs is to do a chart simply displaying the mean of the values represented by the area of all the post-IPCC data sources cast against zero mass change but that's probably a pretty questionable derivation.

2010-09-16 11:19:01Interesting comment
Robert Way

robert_way19@hotmail...
142.162.13.137
Certainly for the purposes of a basic rebuttal that might be plausible but my concern is that the timespan and so on will be a little difficult to deal with. Undoubtedly it is an issue that they have themselves had trouble with otherwise they would have more clear charts. My thinking is that if I just make straight lines across the time period based upon the means that might be fine but getting the exact mean values might require a little effort. I can do a survey of the recent literature myself but then I risk excluding valuable contributions... Furthermore this method might cause confusion with respect to accelerations and depicting them. It is a hard thing to really address... I'm disappointed the glaciological community has not done more to make data readily available.
2010-09-21 21:53:01
doug_bostrom

dbostrom@clearwire...
184.77.83.151

I'm disappointed the glaciological community has not done more to make data readily available. 

Well, figure 2 is a synthesis of a mass of data published individually, in an attempt to make the big picture more available to "the rest of us." The authors probably never imagined we'd have to pander to an audience jealous of every last milligram of glucose pumped into their brains. Maybe we don't.

Failing having a better diagram, why not use the one you've provided? Does it really take a person of above average intelligence to notice practically every box is sitting below zero? I think not. 

 

 

2010-09-22 23:13:34comment
Robert Way

robert_way19@hotmail...
134.153.10.5
Sorry about the languishing. had a personal issue come up and we got hit by a hurricane this week.

Ill try to get on this soon...
2010-09-22 23:27:43Miscellaneous pedantry
James Wight

jameswight@southernphone.com...
58.105.164.221
This rebuttal is quite good but I have some proofreading suggestions.

I suggest you change “the important difference between antarctic and arctic sea ice” to “the important difference between Antarctic and Arctic sea ice”.

I’d change “is viewed as more important” to “is more important”.

“Antarctic sea ice melts anyways” should be “Antarctic sea ice melts anyway”.

“Not Quite” should be “Not quite”.

“Antarctic sea ice is gaining because of many different reasons” should be “Antarctic sea ice is growing for many different reasons”.

“The Southern Oceans are freshening” should be “The Southern Ocean is freshening”.

“Land-ice”, “Land Ice”, and “land-ice” should all probably be “land ice”. (If you prefer one of the others, then at least be consistent.)

And finally, “mm year” should either be “mm/yr” or “mm yr-1”. Since this is a basic rebuttal I’d opt for the former.
2010-09-22 23:55:00Ice shelves
James Wight

jameswight@southernphone.com...
58.105.164.221
You might also want to mention the collapse of ice shelves on the Antarctic Peninsula. Below I’ve pasted some text from a rebuttal to “Ice isn’t melting” which I’m currently working on but haven’t yet posted to the forum:

Ice shelves are thick, floating platforms of ice formed when glaciers flow from the land onto the ocean surface. In 1978, John Mercer identified the collapse of ice shelves on the Antarctic Peninsula as a warning sign of dangerous warming in West Antarctica.

Fast-forward three decades and the Antarctic Peninsula is warming rapidly. Seven ice shelves have collapsed completely, including one covering an area of over 3,000 km2. The weakening of ice shelves has also been observed along other parts of the West Antarctic coast.

Although the collapse of an ice shelf does not directly add to sea level rise, it does cause the glaciers held behind it to accelerate dramatically, dumping more land ice into the ocean and eroding the ice sheet’s stability.
2010-09-23 04:46:08Comment
Robert Way

robert_way19@hotmail...
142.162.11.53
I will get to those revisions that you mentioned later today. With respect to the Antarctic Ice Shelves I suppose you're referring to the accelerations after Larsen A and B in particular. I certainly could include that stuff but as the post is already a bit long and technical it might be something that might overreach here for this response. I might suggest that perhaps there should be a review of ice shelves in antarctica and the arctic done at some point by someone on here. Some of the iceshelves which have been lost are thousands of years old and thus speak volumes about the unprecedentedness of current warming over the last thousand years. I think there was a review article in the cryosphere last year. which looked at all the antarctic ice changes... Just trying to think... Vaughan and Cook 2009 I guess

heres the link
http://www.the-cryosphere-discuss.net/3/579/2009/tcd-3-579-2009.html

has some great images for such a post too.
One of my former professors is actually releasing a book on ice shelves soon (I think this fall) (Dr. Luke Copland, University of Ottawa)

2010-10-26 12:56:38Comment
Robert Way

robert_way19@hotmail...
134.153.163.105
Any thoughts on this piece again..
2010-10-31 14:25:58
Andy S

skucea@telus...
66.183.162.8

Robert,  I'll chime in on a subject I don't know much about, if only to get the ball rolling again. I found the article, well written, interesting and instructive but...

Like others here, I thought Fig2 was too complicated. It was made for the Copenhagen Diagnosis specifically to show how the rate of ice loss has generally increased in more recent measurements (solid boxes) compared to AR4 measurements (dotted boxes). Also, the meaning of the boxes themselves is not that obvious (at least to me): I guess that the height of the boxes represents uncertainty and the width represents the time period over which the rate was measured (ie, not an uncertainty). I'd have to go back to the original references to find out. I see you have added some additional boxes to the figure, as well. The global sea level change line (0.5 mm/yr) is useful for a general discussion of consequences of the ice mass loss but is a confusing distraction on this particular topic (well, it was for me at first).

I suppose you could simply replace the figure with a sentence or two, for example : Multiple measurements made since 1990,  using several different methods, show that the Antarctic Ice Cap is losing mass and that rate of loss is increasing. However, I've got a preference for showing rather than telling, so I would prefer to use a figure. Here are a couple of ideas. The first is the Copenhagen Diagnosis figure that I have simplified and annotated. The second is a figure from here, that was mentioned by Peter Hogarth in the comments on the How do we measure Antarctic ice changes? article.

 

 

 Neither is a perfect solution, I admit. Good graphics are important but they are hard to prepare.

2010-11-03 02:14:08Comment
Robert Way

robert_way19@hotmail...
134.153.163.105
I like your graphics
2010-11-09 13:06:39
Andy S

skucea@telus...
66.183.191.80
You are welcome to use them, of course, and I'd be happy to make any further modifications. The graphics are already loaded on the SkSc site. Just right click on them to get the URL.
2010-11-09 13:07:20
Andy S

skucea@telus...
66.183.191.80
Forgot!
2010-11-09 14:26:11Comment
Robert Way

robert_way19@hotmail...
134.153.163.105
Thanks. I wonder should I do the Wu et al. 2010 post first.. hmm
2010-11-10 04:24:05
Riccardo

riccardoreitano@tiscali...
192.84.150.209
Looks good. In the last paragraph  it would probaby be better not to talk in terms of sea level rise but of mass loss.
2010-11-11 09:21:55Comment
Robert Way

robert_way19@hotmail...
134.153.163.105
Updated
2010-11-18 09:21:01Any Thoughts?
Robert Way

robert_way19@hotmail...
134.153.163.105
any thoughts?
2010-11-25 03:39:58Seems to be languishing a bit.
Robert Way

robert_way19@hotmail...
134.153.14.252
Any ideas? Languishing...
2010-11-25 04:08:02
Anne-Marie Blackburn
Anne-Marie Blackburn
bioluminescence@hotmail.co...
80.42.211.107
Sorry, haven't been around - leaks, starting courses and falling behind, infections... But this looks ready to go.
2010-11-25 05:04:27question
Robert Way

robert_way19@hotmail...
134.153.163.105
Did a recent study disprove any of the Antarctic sea ice stuff?
2010-11-29 13:00:01Published
John Cook

john@skepticalscience...
124.185.20.155
Now the top 10 arguments have all basic rebuttals. Kudos and back slaps all around, people! :-)