Antarctic Ice Shelf Vista (2009 Feb 15)

[geckzilla]

Your use of quotation marks confuses me.

Easily explained.

I essentially agree with what you said.

The first four terms are in quotes because I used them loosely and don't care to defend them.

The term "scientific documentaries" is in quotes because IMO they are really neither.

I see. Ah well, I got my opinion out there, guess one can't hope to accomplish much more in a thread. I hope I contributed even a tiny amount of insight.

Edit: I'd also like to apologize for my first post in this thread in saying that the editors chose a side. It was a hasty and incorrect little quip.

[Rocky Planet]

If one makes the assumption that the Ross Ice Shelf melted in its entirety, along with the balance of the other Ice Shelves in Antarctica, then a total of 1,183,590 sq. Km's of ice would melt. Using Rocky's figure for the total area of the oceans and dividing by the total area of the ice shelves in Antarctica would give 305 times more area. 305 x 5 = 1,525 meters of ice depth would be required to raise the level of the oceans by 5 meters. So I guess that pretty much debunks that theory!

Debunks which theory? I can't tell whether you are saying that the 5 meter figure is correct or incorrect. I say it is incorrect. However, I went back to the original APOD description before posting, and it clearly claims that the Ross Ice Shelf alone would cause a 5 meter rise.

Scientists are watching the much-larger Ross Ice Shelf, which, if it fully collapses, could cause global sea levels to rise five meters over the next few hundred years.

[starnut]

[insult removed - makc]... non-scientists who have selfish reasons for not wanting to believe that human activities are contributing to the climate change beyond what occurs naturally (solar radiation, orbital dynamics, geological activities, etc). Those selfish reasons are mostly economic and personal lifestyles, not scientific. Look up two of the leading global warming skeptics, Patrick J. Michaels

http://en.wikipedia.org/wiki/Patrick_Michaels

and Bjørn Lomborg

http://en.wikipedia.org/wiki/Bj%C3%B8rn_Lomborg

As you can see, the former is now at the conservative Cato Institute and has been funded by the fossil fuel industries, and the latter is a political science professor who has no expertise in scientific measurements and analysis.

Contrary to what you would rather believe, there are plenty of scientific evidences that the current climate change is anthropogenic! You just refuse to accept them for purely selfish reasons!

I have a selfish reason too for believing that we are responsible for the climate change, and it is to hope that we wake up and do something to stop it, or at least not make it worse, for my children and grandchildren's sake.

Gary

[jlfonz]

hmm-huh

Maybe you can explain why the planet warmed up in the middle ages?

How about explaining why a cold planet is better than a warm one?

[BMAONE23]

I'm not sure what this APOD has to do with astronomy. I've noticed that you have very few pictures of the spotless sun recently on APOD. It is probably THE environmental story due to all of its inplications.This is perhaps more topical as the peak average temp of the earth was in 1999 and it has been cooling since. 2008 witnessed the largest drop in average temp on record erasing most of the warming in this century. NASA did anounce October was the hottest on record, they were grossly mistaken or worse.

I don't know about NASA being so mistaken...I live at 37deg n and about 20 miles from the coast (good ocean influence) and I would have to agree having more than 8 days with temps being over 100 deg F in October and also having 9 days so far during the last 30 day period with temps being over 70deg F (during the Dead of Winter)

[BMAONE23]

If one makes the assumption that the Ross Ice Shelf melted in its entirety, along with the balance of the other Ice Shelves in Antarctica, then a total of 1,183,590 sq. Km's of ice would melt. Using Rocky's figure for the total area of the oceans and dividing by the total area of the ice shelves in Antarctica would give 305 times more area. 305 x 5 = 1,525 meters of ice depth would be required to raise the level of the oceans by 5 meters. So I guess that pretty much debunks that theory!

Debunks which theory? I can't tell whether you are saying that the 5 meter figure is correct or incorrect. I say it is incorrect. However, I went back to the original APOD description before posting, and it clearly claims that the Ross Ice Shelf alone would cause a 5 meter rise.

Scientists are watching the much-larger Ross Ice Shelf, which, if it fully collapses, could cause global sea levels to rise five meters over the next few hundred years.

Were your figures refering to the total area (volume) of the ocean or the total surface area of the ocean?

[Rocky Planet]

Were your figures refering to the total area (volume) of the ocean or the total surface area of the ocean?

Surface area.

[BMAONE23]

Not that it would ever get this high but these are speculated maps depicting a catastrophic ice meltdown and subsequent 100 meter mean sea level rice
http://resumbrae.com/archive/warming/100meter.html

[Rocky Planet]

Maybe you can explain why the planet warmed up in the middle ages?

Many are better qualified than I to try to answer this one, but I'll provide this link anyway since a lot has been written on the subject:

http://www.google.com/search?q=medieval+warm+period

Maybe someone can summarize, but I'm better off just letting the various authors speak for themselves.

How about explaining why a cold planet is better than a warm one?

Now that's a good question to start with. I personally like it hot, and for every organism on Earth that likes it cold there is another that likes it hot; as long as enough organisms remain alive in whatever climate exists to maintain a working ecosystem, I see no problem (except maybe for humans) no matter which way it goes. Maybe it's a matter of what else goes with the heat. According to some, high concentrations of CO2 are a problem regardless of temperature. If you like the world as it is with your favorite beach resort and lots of major cities at sea level, higher water might be objectionable. The Earth and life on Earth will survive a greater range of climates than humans will, so our problem may be saving and delivering comfort to ourselves more than the lofty stated goal of saving the planet.

---

I don't automatically buy everything the global warming crowd is selling - I just don't automatically reject it any more.

[jlfonz]

"our problem may be saving and delivering comfort to ourselves more than the lofty stated goal of saving the planet."

Comfort? Does eating food come under comfort? I live in the middle of corn. There isn't ANYTHING but pine trees growing right now. What was that guys name?---uhh Ewell Gibbons (something like that) He was famous because he said we could eat pine cones. (I'm giving away my age). We'd have to live in green houses---guess what will be inside? thats right--greenhouse gases---lol (if you're lucky) Cows will be desired for their flatulence. I'll have to dig up my list. If I remember correctly humans (all human activity including deforestation) are something like 7th on the list of CO2 producers. I think volcanoes were #1 and insects #2.

I cant wait to find out what they called global warming in the middle ages------

[jlfonz]

I had to share this with eveyone. Following a link about Greenland (and the fairytale about it's name) I came upon this website from a AGW preacher.

His statement:

**It is my opinion that those who still proclaim that "the jury is still out" or that modern-day climate change is natural, are either ignorant about the scientific evidence or are politically motivated to ignore it.**

His Name: Posted on his site---even his phone which I will not post

Scott A. Mandia
Professor - Physical Sciences
T-206 Smithtown Sciences Bldg.
S.C.C.C.
533 College Rd.
Selden, NY 11784

And besides the fairytale about the name having green in it to dupe settlers into coming it had the following statement.

**Before the year 1300, ships regularly sailed from Norway and other European countries to Greenland bringing with them timber, iron, corn, salt, and other needed items.**

I couldn't pass it up. My e-mail to him--

Dear Sir,
Even you have to know that the europeans did not bring corn with them for barter--in the 1300's.
Such a wildly blatant error casts doubt on everything else written.
I am tired of hearing the fairly tale about calling Greenland "Green" to attract settlers. Don't you think they would have moved on to New Foundland or back to Iceland if that were the case?
I apologize for the bluntness of this e-mail but I'm getting thouroughly disgusted with all of the propaganda being disguised as "progressive thinking"
You know--I learned in 2nd grade when and where corn was first introduced to the civilized world.
Signature

Sorry--but this IS relevant to this discussion. This guy is teaching in America.

[StACase]

... You know--I learned in 2nd grade when and where corn was first introduced to the civilized world ...

The definition of "Corn" varies from place to place. I Googled " Corn British Definition" and came up with:

Chiefly British Any of various cereal plants or grains, especially the principal crop cultivated in a particular region, such as wheat in England or oats in Scotland.

[casomega]

Yeah, and this years arctic ice is reported to be back at 1979 levels - yeah!! Whatever that means. I mean, we don't have 1978 levels do we!!!

http://nsidc.org/seaice/characteristics/difference.html

This site clearly shows antarctic sea ice has returned to normal, whatever that is. Besides, it melts a lot every summer, which is when this picture was taken.

These Antarctic Sea Icesheet images clearly show the difference between 2007 ice sheet minimun and that of 2008
and yesterday Feb 14,15.
There is a clear and undeniable decrease in summertime sea ice especially near the more massive West Ice Shelf. Your indicated site seems to only show summer vs winter ice averages.

And although this graph does indicate a relatively stable annual ice coverage in the south, this one indicates a gradual but significant annual decrease in the northern hemisphere, Where man has more influence due in part to a vastly larger presance of industrialized nations and human populations.

[vofl]

Hej Robert J. Nemiroff - In 15feb2009 apod you write:

Scientists are watching the much-larger Ross Ice Shelf, which, if it fully collapses, could cause global sea levels to rise five meters ...

FORGET about that sea levels to rise : Shelf ice is already floating into the ocean, so sea level has already rised. ( Archimedes law)

I think, you need to correct your mistake.

Anyway ... I am living in a country, where the northern part still is rising after last ice-age. So, to maintain sea-shores we need sea-rising!
Sea-rising might be a good thing, not a disaster ...

/ vofl - Allerød, Denmark

[Chris Peterson]

Hej Robert J. Nemiroff - In 15feb2009 apod you write:

Scientists are watching the much-larger Ross Ice Shelf, which, if it fully collapses, could cause global sea levels to rise five meters ...

FORGET about that sea levels to rise : Shelf ice is already floating into the ocean, so sea level has already rised. ( Archimedes law)

I think, you need to correct your mistake.

I think you also need to give this some more thought. The ice that is melting is freshwater. When floating freshwater ice melts into saltwater, the level rises. Archimedes' law indeed!

However, the statement as given is confusing. If the Ross Ice Shelf is lost, it may destabilize the West Antarctic Ice Sheet, which is already warming. The WAIS (the part that is above sea level) contains enough water to raise sea level by 5m. The sea level rise from the Ross Ice Shelf itself would be much smaller (but still problematic for many coastal areas).

[Redbone]

The density of freshwater is 62.4 pounds per cubic foot. The average density of seawater is 64.0 pounds per cubic foot. The difference between the two is 1.6 pounds per cubic foot. The difference between freshwater and seawater as a percentage by weight is 1.6/64 = 2.5%.

Floating freshwater ice, melting in seawater, will increase the total volume of water by 2.5% of the amount of melted freshwater.

It is generally accepted that if all of the floating icepacks melted, it would not significantly affect sea levels because a 2.5% increase of the icepacks' volume due to the density difference between fresh and salt water is simply too small to have a measurable effect.

[neufer]

If the Ross Ice Shelf is lost, it may destabilize the West Antarctic Ice Sheet, which is already warming. The WAIS (the part that is above sea level) contains enough water to raise sea level by 5m. The sea level rise from the Ross Ice Shelf itself would be much smaller (but still problematic for many coastal areas).

If the Ross Ice Shelf is lost, then the entire ecosystem that depends on dark cold water underneath an ice sheet is totally disrupted.
(Sea level rises are irrelevant for this particular situation.)

http://www.imdb.com/video/screenplay/vi300482841/
http://www.imdb.com/video/screenplay/vi367591705/

[Rocky Planet]

If the Ross Ice Shelf is lost, then the entire ecosystem that depends on dark cold water underneath an ice sheet is totally disrupted.

The collapse of Larsen B has revealed a thriving ecosystem 800 m (half a mile) below the sea. "Despite near freezing and sunless conditions, a community of clams and a thin layer of bacterial mats are flourishing in undersea sediments."

[CraigInCHinaLake]

I would suppose that the REAL issue is what is it that is causing the loss of ice in a particular area, even regionally, or globally. And I would also suppose that inspiring discussion of political/scientific discussions isn't what APOD is really about. Therefore I agree with 'verkle'; pictures of scientific phenomena are great, and may make you think, but posting 'charged' text with them isn't really within the charter for APOD is it?

If anything beyond selective data were presented we COULD have a discussion on the merits of global warming, but then APOD would still not be the right venue.

Disappointing performance by APOD to say the least. Post the pictures, leave the opinion out.

China Lake, CA

[Chris Peterson]

...posting 'charged' text with them isn't really within the charter for APOD is it?
...
Post the pictures, leave the opinion out.

It's fair to ask whether this image is really "astronomical", but that's all. There is no more "opinion" or "charged" text here than there is talking about the Big Bang, dark energy, or stellar nucleosynthesis. Like those things, global warming is well observed and understood (partly) in the context of current scientific theory- theory that is accepted as generally accurate by the majority of the scientific community. The fact that many people who have little ability to understand and interpret modern science have a problem with an idea is certainly no reason for the APOD editors to refuse to discuss it.

It is fundamental to NASA's charter to study the Earth, its climate, and its atmosphere- perhaps more fundamental than studying deep space. The the extent that APODs feature work sponsored by NASA, images like this- with good, accurate captions- are perfectly reasonable.

[Rocky Planet]

... we COULD have a discussion on the merits of global warming, but then APOD would still not be the right venue.

Compare the activity in this thread with the lack of activity in this slightly more appropriate venue (in the Café). You gotta have your discussion where the participants participate, even if it's not exactly the "right" place. IMO, it is still more productive - and interesting - to respond to a "charged" description (or to publish a "charged" description to stimulate the responses) than to waste our enthusiasm responding to the same old trolls on the same old topics. I agree that selective data is a problem, but how are we going to get around that one in less than 100,000 words? Even when APOD discussions start looking like the Wild West (in relative terms), they still stay more coherent than a lot of other fora on the web. I think we're having a good time here despite the politics - I've been characterized as everything from the poster child for climate change denial to a blind follower of the AGW lobby, yet I survive and enjoy.

[BMAONE23]

I would still to see a follow up image that presents current conditions in the area of the APOD image. I can only imagine the dramatic difference that has occurred and, if the intention of the APOD text was to mention the difference, then please show us the difference. But be certain that both the vantage point and date of the year are the same.

[neufer]

There is no more "opinion" or "charged" text here than there is talking about the Big Bang, dark energy, or stellar nucleosynthesis. Like those things, global warming is well observed and understood (partly) in the context of current scientific theory- theory that is accepted as generally accurate by the majority of the scientific community. The fact that many people who have little ability to understand and interpret modern science have a problem with an idea is certainly no reason for the APOD editors to refuse to discuss it.

It is fundamental to NASA's charter to study the Earth, its climate, and its atmosphere- perhaps more fundamental than studying deep space. The the extent that APODs feature work sponsored by NASA, images like this- with good, accurate captions- are perfectly reasonable.

APOD really shouldn't have left the impression that the Ross Ice Shelf was probably also on the verge of disintegrating:

<<Explanation: Over the past several years large chunks of the 200-meter thick Larsen B Ice-Shelf have been breaking off and disintegrating. The cause is the local high temperatures of recent years, part of a planet wide climate change called global warming...Scientists are watching the much-larger Ross Ice Shelf, which, if it fully collapses, could cause global sea levels to rise five meters over the next few hundred years.>>

Considering that the Ross Ice Shelf trend is the opposite of the Larsen B Ice-Shelf trend:


______________________________________________________________________________

[BMAONE23]

Art,
You must realize though that the charts you presented are indicators of "Sea Ice" near the Ross Sea and not indicative of "Shelf Ice" extent. The increase of Sea Ice near the ice shelf only serves to act as a buffer against the potentially erosive tidal effect. Also increased calving of the ice shelf would act to aide in the increase of sea ice in the region. Further, sea ice in the region has proven to become more and more annual rather than residual in the Ross Sea area.

[BMAONE23]

http://images.google.com/images?q=antarctic+ice+loss



The picture above shows the Ross Ice Shelf as having an area of about 473,000 square kilometers. The area of Earth's oceans is about 361,000,000 square kilometers. That makes the area of the oceans 763 times the area of the Ross Ice Shelf. If dropping the entire shelf in the drink and melting it would raise sea level 5 meters, then the amount of the Ross Ice Shelf standing above sea level must be 763x5 or about 3800 meters. The maximum thickness of the Ross Ice Shelf is less than 1000 meters, the average thickness is less than that, and most of it is already under water and so would not raise sea level if melted. So is my arithmetic wrong, or is the 5 meter claim a gross exaggeration? I've left the density of the ice out of the calculation, but it shouldn't account for the difference.

Rocky,
Try your math again. The problem is that both regions stated are in square kilometers which only refers to surface area and not volume or cubic meters.