Talk:Antarctic ice sheet
|WikiProject Glaciers||(Rated C-class, High-importance)|
|WikiProject Antarctica||(Rated Start-class, High-importance)|
The article says, "Recent satellite data reported by NASA shows evidence that the total amount of ice in Antarctica has increased in the past few decades." However that data is now about four and a half years old (from August, 2002,) so it is hardly "recent." Also, more recent data suggests that the Antarctic ice sheets are actually melting now. See "Antarctic Ice Sheet Is Melting Rapidly" and "Antarctic ice sheet losing mass, says University of Colorado study" from March, 2006. Do we have an expert who can update this? If not, I'll do it, but I thought I'd check first. -- HiEv 12:12, 7 January 2007 (UTC)
- Wikipedia doesn't need experts to update articles. Measuring the net gain or loss of ice over an entire continent is not an easy thing to do, even with satellites. The article should reflect the fact that these are individual studies, each of which is saying something slightly different. Such is science. But feel free to update the article yourself. -- BlueCanoe 01:52, 24 August 2007 (UTC)
East Antarctic Ice Sheet
Where is the article on the East Antarctic Ice Sheet? The West Antarctic Ice Sheet has its own article, and rightly so. The two "halves" of the Antarctic Ice Sheet are very different from each other with respect to geography, origin, age, stability, climate, etc. If I get time I'll start the article but anyone else should go for it! -- BlueCanoe 01:52, 24 August 2007 (UTC)
Am new to contributing here, please forgive any faux paus.
This page http://en.wikipedia.org/wiki/Ice_sheet says "Around 90% of the fresh water on the Earth's surface is held in the ice sheet" and this page http://en.wikipedia.org/wiki/Antarctic_ice_sheet says "approximately 61 percent of all fresh water on the Earth is held in the Antarctic ice sheet"
Ice Density and Ocean Levels
This article states that because the density of freshwater ice is different from saltwater, the ocean levels will still rise if the floating ice melts. However, my understanding is that the effect on ocean levels depends not on the density, but on the weight of the ice or water, and how much seawater that weight of ice displaces. My understanding is thus that it doesn't matter how dense freshwater is compared to saltwater. Is this the case? Eunsung (talk) 02:01, 22 January 2009 (UTC)
I agree with this, I believe its because of Archimedes principle of buoyancy.
the original paper says this:
1g of ice would displace 1g of salt water(0.98cm3) when the ice desolves it will add 1.0cm3 of fresh water this is the volume increase. but in my opinion this fresh water woudl then uptake salt of its own from the sea increasing its own desity to that of salt water (you wouldnt have a section of fresh water floating in salt water) However because alot of the ice is not floating but resting on a solid land mass (at least that is what i understand from this article) then it would be based on density (ice is less dense than water so therefore you would get an increase in volume..dunno by how much though)
OK i tried to explain it a bit better. however my writing skills are really bad so it might need a touch up by someone of greater skill :D. also would be handy to find out whether the density change of salt water is linear with concentration, to give an idea if there would be a volume increasePaddycolver (talk) 09:51, 23 January 2009 (UTC)
I think this whole section is in the wrong place. This is a wikpedia article on the Antarctic Ice Sheet, which means grounded ice on land not floating ice. The point about salinity is made on the page, Ice shelf. But could do with being expanded upon there along the lines of adding the academic references used here. The effect is very small. If you look at the Jenkins and Holland article, that is cited here, they mention that the extra 2.6 % due to salinity is offset a bit by the lower temperature of the ice shelves. The mass balance (changes in total amount of ice) info on the Antarctic Ice Sheet needs major updates as mentioned at the top of this discussion and it is confusing to have such a large section on an effect that is not directly relevant. Polargeo (talk) 19:11, 27 January 2009 (UTC)
Ah now I get it. The point was initially added to the page over a year ago to explain why ice that is already floating could raise sea levels when it melts. This was a misconception (due mostly to confusion spread by global warming sceptics) that the melting of floating ice is the main issue here. The real issue is the amount of ice passing over the 'grounding line' from the land into/onto the sea and how much this is balanced by precipitation (mostly snow) falling back onto the continent. The change in sea level due to salinity differences is not directly relevant to this. Polargeo (talk) 19:34, 27 January 2009 (UTC)
First paragraph states if all the ice sheet melts, it would raise sea levels by 70m, with no reference. New report using ESA's Cryosat data shows melting twice the rate as last measurement, leading to 0.43mm sea rise per year, and mentions 58m if all the ice melts. Reference BBC News 19th May 2014  If nobody has objections, I will update page with this new info shortly. Tony Spencer (talk) 14:56, 21 May 2014 (UTC)
ice density section removal
I would like to suggest removal of this paragraph based on the comments above. In doing so the similar section on the ice shelf page (where this information is better placed) should be beefed up a bit. Any thoughts. I will leave it for a while Polargeo (talk) 14:44, 28 January 2009 (UTC) Another thought. Maybe a sentence on this effect can be left in this page somewhere, with a link to the ice shelf page of course. Without having a huge discussion on the issue on this page where it is not as well placed. Polargeo (talk) 09:30, 30 January 2009 (UTC)
I actually don't think that the prominance of recent melt and warming on this page, including two images is particularly helpful. It gives the impression that this is in some way affecting the whole mass balance of the Antarctic Ice Sheet. It is not. At present changes in surface temperature are tiny and have negligable effects on the ice sheet. It sends a confusing message. There are many more important factors at work on the ice sheet at present. That big red blob in the warming image over West Antarctica represents around 1 degree over half a centuary, with average temperatures in this region somewhere between -20 and -30 degrees. Then add on the melt image which just repesents the small amount of surface melt Antarctica experiences (Mostly a mere glazing of the ice surface). This melt does not reach the base of the ice sheet, does not run off into the sea and has no direct effect on the movement or mass balance of the ice sheet. Therefore this page, whilst not being inaccurate, is simply getting confusing to the general public and needs more balance. Polargeo (talk) 13:27, 20 February 2009 (UTC)
Location, here best?
- Big Antarctic ice sheet appears doomed; Warming climate predicted to trigger collapse of Filchner-Ronne shelf by 2100 June 2nd, 2012; Vol.181 #11 (p. 5) Science News.
Suddenly talking about sea ice makes it confusing that this is distinct from the ice sheet if the reader is not familiar with the terms.