Antarctic Melting

Just a quick note. There is a new paper by Velicogna and Wahr in Science today (you have to pay) which attempts to assess the overall mass balance of Antarctic ice by satellite measurements of the earth's gravity field.

Using measurements of time-variable gravity from the Gravity Recovery and Climate Experiment (GRACE) satellites we determine mass variations of the Antarctic ice sheet during 2002-2005. We find that the ice sheet mass decreased significantly, at a rate of 152 ± 80 km3/year of ice, equivalent to 0.4 ± 0.2 mm/year of global sea level rise. Most of this mass loss came from the West Antarctic Ice Sheet.
There are several cautions here. That ± 0.2mm is a 1 sigma error bar, so this is only a two-sigma result. Furthermore, it's a short time period, so we don't know how this fits into an overall trend. Finally, it's a new method, so if the referees missed a methodological problem, that will show up in time. In particular, the ice mass loss signal emerges as an offset to a sizeable correction due to post ice-age rebound which has to be estimated from ice history models. That sounds a little scary to me - I'd feel better seeing this replicated with other independent analyses.

All that said, it's certainly not in the good news column. If this result holds up, it suggests that Greenland and WAIS are contributing roughly equally to sea level rise at present.

We discussed sea level rise before in

Yep, just more news to help prove Peak Everything.  Hopefully, no under-ice volcano erupts to really send the ice surging into the sea.  The Bentley SubGlacial Trench is the deepest point on earth not under seawater at 8326 ft below sealevel.  A significant volcano here could break up the entire Western Antarctic Ice Sheet in less than 20 years.  That would be really bad news for humans.

Bob Shaw in Phx,AZ  Are Humans Smarter than Yeast?

There was a great article a few weeks ago in the New Yorker that I meant to bring up. When they did the post Katrina measurements of height above sealevel they found little to no change at first. Using GPS, they discovered that the problem was that they were using benchmarks that had also sunk over time - not only had Katrina reclaimed more land for the sea, what was thought to be as solid above sealevel land is now even or below it. Methodology matters!
Some interesting mental images there... but when you say:

"The Bentley Subglacial Trench is a vast trench in Antarctica. At 2,555 meters (8,326 ft) below sea level, it is the lowest point on the surface of the earth not covered by ocean, although it is covered by ice. It is similar in size to the nation of Mexico.  [This is huge!  Even if it was not covered by ice, a human could not go down to the very bottom because the vastly increased air pressure would overcome your lungs diaphramic muscle ability to exhale; you would need a deep sea diver's pressure suit to explore this area"

I get confused. Anglogold's Western Deep Levels in South Africa is the world's deepest mine at 12300 ft.I think,  and as far as I know no pressure suits are required to work at its lowest levels...

I think the statement about the breathing is wrong. If you could dig out the ice over the Bentley, the air  pressure would be like what scuba divers breath while 20 feet underwater.  There wouldn't be any problem breathing, though you might get the bends if you departed too quickly after a very long visit.  

I think this trench is cut off from the ocean. It is hard to tell, I could not find any maps that clearly show the topology of the Antarctic land under the ice, but if the ice were gone, the ocean would probably not rush into the Bentley, so it would stay dry. So if a volcanoe were to melt ice there, it should not destabilize anything, just make a lake. There would be no lubricated glaciers quickly sliding off of the Antarctic.

I did find this:

Hello Everett,

Thxs for responding. Yeah, on second thought, I agree with you that I blew the pressure assumption.  If the caldera was as big as Yellowstone, or similar to previous Antarctic calderas [even bigger than Yellowstone], this could potentially be filling in the trench displacing all that water.  But the big problem would be from the predicted 1500 ft or more of uplift from earthquakes, other volcanoes spouting off, and ejecta melting the main Antarctic ice sheet.  The Western Antarctic Ice Sheet [WAIS] is only good for 20ft of sea-level rise-- the other ice sheet is good for 190 ft-- REAL BIG PROBLEMS for us.

My tutorial was highly speculative-- I bet most real scientists would laugh at the whole shebang sliding off in a short twenty year timeframe-- A 1,000 year gradual process is probably much more likely.  But who knows, Nature can be very surprising.

Bob Shaw in Phx,AZ  Are  Humans Smarter than Yeast?

Somebody is confusing water with air. I seem to remember air is about .03 lb/ft3 at STP, so 8300 ft would add around 2 psi, maybe a little more with compression.
On the plus side, this ice will become a lake that will not empty into the sea.
If it was not covered by ice it would be covered by water - I assume that's the point here?
No pressure suits but they need to blow in lots of refridgerated air to keep the miners cool.  Its hot and the ground swallows up gaps.  Its a hostile environment.
Bob, seriously man...this can't happen.  Way too long.  What would be better is for you to get an online space of your own and then provide a link.  We can't have comments that long, it's not the purpose of the space.
Sorry, Go ahead and delete!  I can email to anybody interested!  I just thought I would save everybody a lot of googling time--I had over 100 hours in this essay.

Bob Shaw in Phx,AZ  Are Humans Smarter than Yeast?

Bob, nonononono!  I think the time you spent is great and the information very very very very valuable.  I just wish you'd get a blog, put it there, and then link it!  totoneila.blogspot is available!  

(I'm encouraging you...I like what you did.  It just was a blogpost (if not a book), not a comment!  That's all!)

Hey Goose,

Help, I am confused.  I posted a variation of this same post on the forum Yahoo:AlasBabylon with no problem #24085.  The moderator, the Great Scott, had no problem with its length, and he too was impressed with its content.  It is free for anybody to read if they join [also free], but I cannot make an autolink to it.  Other AB posters have included different articles that are much, much longer than mine-- no problem.  Is there a technical difference in equipment & software between these forums, or just a different social norm of netiquette culture?  Sometimes I feel like a stranger in a strange land on TOD, help me conform.  :]  Sorry to make you have to do that work, but I thought I would save everybody the gobs of research that I did.  

I just never thought I needed a personal blog as long as my articles are available in the AB archives.  I have got hundreds of them.  I have even seen some of my postings reposted on Italian websites and plagiarized elsewhere.

Clue me in, if you can.


It's just that YahooGroups are a lot different in their workings...entire posts can be distinct emails.  In here, we're trying to have conversations/discourse about a topic.  A really long comment like that completely hijacks other commenters' ability to discuss what was posted, making your comment the subject of the comment!

What I would suggest on these kinds of topics is, in the comments, post an executive summary that interests people, then link that material you want them to read posted elsewhere (again, perhaps on your blog that you're going to set up today for free over on blogger (because you should!), because work like yours is really good, and should be out there influencing the discourse!)  You could post your best work on your blog that way, and then it's outside of the AB archives so that others can hear your ideas.

Again, this is one of those "unwritten rules"'s just that one commenter running the comments usually just pisses people off, then we get emails in the TOD inbox (as we did today), then I have to do something like this.  :)

Thxs Goose,

Okey-Dokey, I will flail away at creating a blog after doing some more lurking first. See-ya Gang!

Bob Shaw in Phx,AZ  Are Humans Smarter than Yeast?

Prof. Goose;
You talked about posting links and here is a
good one about snow and ice and guess what?
It's free.
I agree with PG.  You need your own Web site or blog.  Posting a long e-mail to a mailing list or Yahoogroup is a much different thing than posting one to a blog like this.  

There are many sites that offer free Web space or blogs.  If you post your articles to your own Web site or blog, you can post links to them.  Much better than dumping War and Peace in the middle of thread here, or forcing people to join a Yahoogroup. (Many people will not sign up with Yahoo anyway, due to their privacy policy.)

Personally, I like  It offers not only blogging, but file upload for text, audio, video, and image files.  It's a bit slow to upload sometimes, but download is usually fine.  And it allows remote linking.  

Seriously, people, keep the posts to a decent size. Use links. It takes forever to scroll through some of this stuff after you've already read it three times. Let the editors post the long pieces.
Just a useful tip: using Firefox browser I use the find feature (ctrl f) and put it "[n" and thus it brings you to new posts only, which makes it so much easier to follow along!
Thanks, that is saving me so much time.
I found your lengthy tutorial on Antarctica fascinating. While it may be too long for the format and purpose of TOD, I would encourage you to continue with the good work. A blog of your own would be a great idea.

I learned may things from your post, and now am a whole lot smarter about Antarctica. Quite a wierd place - almost sounds like another planet! It's hard to picture a temperature of -129 degrees F along with hurricane-force winds. Due to its shear size, it sure seems like Antarctica has the potential for affecting a lot of things 'up here'.

Bob, seriously man...this can't happen.  Way too long.

Why was it 'bad'?   It was great content.  Compelling.   Perhaps totally wrong and other events (say a global themonuclear war or the sun becoming a red giant) would render the eventual removal of ice and water level a non-issue.

Why not copy it and make it a topic for discussion all by itself as its own bad self.    Natural disasters/crop failures/et la are now made less painful because of the release of the energy of stored sunlight.  The 'worse case' outlined in that post would effect some nations by removing them from the globe, and other nations would have to have 1/2 of their population move.  A bigger issue would be the placing underewater of all that costal buildings and production capacity.  So there IS a peak oil tie to such an event.

Thanks, Stewart for all the attention you are giving to global heating/climate change. I can't seem to  make sense of trying to mitigate peaking carbon fuels without integrating CC. Of course it would make even more sense to me if human population overshoot, habitat destruction, species die-off, and an unsustainable growth dependent economic system were factored in also. Unfortunately that would seem to undermine the quick fix scenario syndrome rather drastically, but isn't that the real reality? Of course, I could be missing some efficiency factor in the piece-meal approach.
Maybe one good point. After global sea level rise and drowning of Netherlands there would be some relatively inhabitable parts in Antarctica where stuck-up Dutch guys could displace themselves.
Oh! And maybe my grandchildren (if I ever make the breeding) could pick up bananas in Moscow. No matter, there won't be enough oil to transport them from Ecuador.

I heard somewhere, there are deep-water oil fields near Antarctic coast but no international agreement on the rights below latitude 60.  ???

Maybe it will be warm enough to grow bananas in Moscow.  ;-)

Hey, Amory Lovins grows bananas in Colorado.

How does a gravity measurement distinguish between rock and ice?  I mean, if this is a new technique, how do you separate out the possible tectonic element?  Does anybody know?
According to this BBC report this is a major problem. They are attempting to estimate rock movement from GPS recievers on rocky outcrops but admit there are not yet sufficient of these.
Yeah - this is what I was alluding to in my comment in the post. Most of the imputed ice mass loss is what is required to balance the modeled rock rebound from the last ice age. So their result is very dependent on how good the model of the ice history and resulting rock rebound is.
Geological uplift (like in Scandanavia) is a slow process going on over thousands of years since the last glacial maximum (about 20/kya). I find it very hard to believe that this is a significant variable in recent findings about the mass balance of the Antarctic ice sheets, especially in the West Antarctic penisula where most of the thinning and melting is occuring. So, I can't take this kind of factor seriously.

The real problem is that the erosion of these glaciers is occurring on a much faster rate than was anticipated by prior modelling.

Here's what the paper has to say on the subject. PGR = Post-glacial rebound.

Re: [the last two paragraphs] and "Note that our uncertainty accomodates all plausible PGR contributions, and that removing even the smallest such contribution implies an ice loss".

OK, I stand by what I said. Plausible PGR contributions? Since when has the Antarctic been subject to geological uplift in the many thousands of years since the last Glacial Maximum? -- not to mention perhaps 35 millions before that? And these results should not be "averaged over all Antarctica". What's happening in West Antarctica and what's what's happening in the Eastern Antarctica big ice sheet don't necessarily correlate at all and why would we expect that? The geology and climate considerations are completely different. Maybe it will snow more in East Antarctica and erosion in West Antarctica won't surpass that, so the ice sheets in these two regions will remain "in balance". That would make the "averaging approach valid" I suppose. As for calculating all this, that is being worked out but I haven't see any significant evidence that accelerating erosion contributing to global sea level rise from West Antarctica is being compensating by an increase in ice cover in East Antarctica.

Thanks for the quote from this Science article I haven't seen.

best, Dave

Well, but you had said "I find it very hard to believe this is a significant variable", whereas they say that "PGR effects are large and must be independently modeled and removed", and "The PGR much larger than the uncorrected GRACE trend".
There already exist airplanes like this one that fly over the Antarctic ice measuring gravity, and with radar they can distinguish rock from ice, so I am wondering why they would not see this hypothetical disappearance of ice with their much greater local resolutions?  The satellite technique (details here) is by comparison very crude (they're just measuring the varying distance between two satellites as they wing around the earth together) and can barely distinguish East and West Antarctica.    

I'd also imagine if ocean rise must now to be attributed to Antarctica (as many media reports of this story are simply stating as fact), that would imply ocean rise due to all other factors elsewhere must be less than previously thought - since the data is not that "oceans are rising faster" than expected but that the West Antarctica area is unexpectedly losing mass.

Might this not be the kind of Rorschach-staring science Michael Crichton - curse his soul - was pointing at?    

Those whose souls you curse may rise to haunt your blithe certainties--especially your beliefs turn out to be quite wrong.

You can say what you like about Chrichton, but he did his homework. Also, in the more than 800 reader reviews of STATE OF FEAR, I noted that those who seemed to have the best scientific credentials often gave the book five stars, while those who hated it were often typical chattering-class pundits who never got beyond seventh-grade algebra.

The short answer is: It can't.  The only thing it is measuring is the change in the accelleration of gravity.  The gravity is caused by a change in mass underneath the satellite.  It would be an assumption that it is the loss of ice, verses changes in the land mass.  However, given the timescale we are talking about (3 years), ice loss is probably a good bet.
This global warming thing is becoming mildly interesting.  I think we should consider begining to think about maybe one day starting to study it a little bit.  Who knows, it might be worth funding to the tune of a couple of hundred bucks.  Naaah.

Click to enlarge
I started to say, off topic, but not really. I'll make it short: today's (3/3) WSJ had an article on China building more coal-fired power plants, i.e. backing off gas powered ones because of rising prices. China's already suffering from terrible air quality. We'll do no better.

Breathe now, while it's easy. No, I'm confused, move inland -- this is a water thread, not an air thread.

Let the denial begin now!
A general question regarding the geophysics of polar melting:

The earth is spherical object spinning about an axis. It has a certain distribution of mass and hence a certain moment of inertia about its axis of rotation.

Now, If I remove a certain amount of mass (ice) from the polar regions, where the radius from the earth's surface to the axis of rotation is relatively short, and redistribute that mass further out toward equator, where the radius is much greater, will I not have increased the overall moment of inertia of the earth?

And by doing so, will not the rotational speed of the earth decrease by some slight amount, in the same way that a figure skater slows down by extending her arms?  

Has anybody calculated the magnitude of this sort of effect? What about wobble?

Speaking of wobble...check this out:

The Anomaly In The  Earth's Wobble Continues
The Polar Motion Anomaly of 2005/2006


Thanks, Les.

I didn't read all of itl yet, but from what I skimmed, it looks like pretty heavy stuff.

I can see now that there are a great many factors affecting the rotation of the earth. I had completely forgotten about the effect of the moon causing a periodic bulging. Then you have tectonic plates doing their thing, and molten gooey stuff sliding around inside.  I guess that from the standpoint of spin dynamics, the earth is more like a giant water balloon filled with viscous material that is continually slipping and sliding and being pushed and pulled by outside forces (the moon).  

So far from what I read of the article, I didn't see any mention of the possible effect of polar ice caps melting.

Chance are the mass of the water on the surface is not even the mass of the first 300 feet of rock surface below water and land coverage.  All that water though large to us, is small in over all volume of the earth.

I come at this from a background in digital mapping of the earth's surface, both dry land and water covered land. The changes that occur to maps over a set perios of time causes great head aches to those that have to keep up with it all.  

The company that maps the US southern coast is likely 3 year behind in updating total data sets, just because of last 2 seasons of hurricanes,  Not to mention ice melt too.

Fun Fun Fun for some guys, I am glad I went into full time Writing and Koi breeding and Am moving further inland.

Any One in Colorado give me a heads up.

Interesting as usual. I do think that we should all try to use the term "global meltdown" instead of the more benign "global warming." I have an idea that it might spread outside TOD into the mainstream. I think it's more dramatic, more accurate and hits home. It's an attempt to re-define our use of language and thereby hopefully redefine the agenda. I know it sounds slightly more agressive, but that's the point in my opinion. We need to be more proactive and create debate and controversy, if we to get people thinking and get things moving. How about it guys?
Have you ever read Don't Think of an Elephant, by George Lakoff?

There's an example of the kind of thing he does here.

Thanks, that was interesting. Having written so much fiction I suppose I'm kind of interested in language! I've read so many graphs, charts and stacks of numbers on TOD over the past year, that sometimes I've ended up cross-eyed. I kind of feel if these ideas are going to gain traction we've got to use words, arguments and language a lot more creatively. Thanks again.
I think the term 'global meltdown' is a very nice touch!

It is both literal (arctic ice melting) and highly evocative (nuclear reactor meltdown or total collapse of a system).  

It certainly would get much more attention that 'global warming', a term that I think many people are bored with because they associate it with those pesky whiny  environmental greenies.

Hmmm. I like the general idea, but what about "global melting" rather than "global meltdown". The former seems descriptively accurate (mountain glacier all on their last legs, Greenland, Antartica probably starting to melt), whiile the latter, with the nuclear reactor connotation, doesn't draw the write picture.

I agree with you that stories and words, anecdotes and emotions are necessary for communicating the truth to the public effectively. However, they are almost useless for determing what the truth actually is (at least about any large scale phenomenon) - for that one typically needs graphs and numbers and statistics.

Duh - "write" -> "right". In haste...
You have touched on one of the Very Most Fundamental (VMF) questions: What is truth? What is the nature of truth? How can we know it when we find it? Or, in other words, what is the nature of knowledge?

Plato believed that mathematical truth was the deepest truth, that to understand and know and explain the universe one had to first get at the underlying mathematics. Recall the Alegory of the Cave--most of us think we have notions of the truth, but all we really see is flickering shadows.

Aristotle, on the other hand, believed that there was an empirical reality more fundamental than mathematics. He was first and foremost a marine biology student, and he had been educated by his physician father in empirical methods. (e.g. Keep King Philip alive and healthy, or you die.) Plato started out as a poet, and I have noticed an affinity between poets and theoretical physicists: Both of them aim ruthlessly to eliminate the nonessential and get at the meat of the matter.

It has been said that all of us are either Platonists or Aristotelians, and there is something to that. Clearly, Stuart, you are an Aristotelian (a scientist), and though I love Plato, at heart I too am an Aristotelian.

Math describes reality.

Math itself is a language, a form of logic, a powerful way to deal with reality--but in my opinion is at bottom a tool to understand "reality" rather than the "reality" itself.

These are deep empistemological and metaphysical waters, however--far too deep for drilling:)