Kettle Posted July 10, 2003 Posted July 10, 2003 Some nice person bought me a "Book of Useless Information" a while back and one of the entries caught my interest: H2O expands as it freezes and contracts as it melts, displacing the exact same amount of fluid in either state. So if the northern ice cap did melt, it would cause absolutely no rise in the level of the ocean Equipped with just a GCSE in Dual Science that was news to me (the bit about oceans - not the freezing and contracting) - is there anyone more learned in these matters that could corroborate this? Also (question #2) I remember back in the 1990s there seemed to be a group of scientists who said that a significant portion of the effects of global warming could be attributed to the fact that we are still at the tail end of the most recent Ice Age so obviously temperatures across the globe will increase until we fully emerge. They seem to have been a bit quiet of late (and everyone is once again talking about pollution) - has this theory been thrown out? Cheers
JaKiri Posted July 10, 2003 Posted July 10, 2003 It's true. There would be a slight rise in sea levels, from the melting of antarctica (it's on land), however most of the change would be from the thermal expansion of water. And we don't know about the rest of it.
Sayonara Posted July 10, 2003 Posted July 10, 2003 Yes, ice expands rather than contracting, because the bonds are less space efficient in the solid form or something... That's why ice floats in water - it's less dense.
JaKiri Posted July 10, 2003 Posted July 10, 2003 Originally posted by Sayonara³ Yes, ice expands rather than contracting, because the bonds are less space efficient in the solid form or something... That's why ice floats in water - it's less dense. Water's odd stuff, and it's quite likely that this property is the only reason life exists.
Sayonara Posted July 10, 2003 Posted July 10, 2003 Ages ago when Focus magazine was new and less crappy, I sent that in to the questions page. They printed it with a picture of an iceberg and everything \o/
Kettle Posted July 10, 2003 Author Posted July 10, 2003 Yup - I knew about the basic properties of ice (that it floats, is less dense etc) but it was the part about the oceans not, in fact, rising should the ice caps melt that took me by surprise (just never put 2 and 2 together I guess - either that or I'm a sucka for hollywood science )
JaKiri Posted July 10, 2003 Posted July 10, 2003 Originally posted by Kettle Yup - I knew about the basic properties of ice (that it floats, is less dense etc) but it was the part about the oceans not, in fact, rising should the ice caps melt that took me by surprise (just never put 2 and 2 together I guess - either that or I'm a sucka for hollywood science ) As I said, thermal expansion of water
Kettle Posted July 10, 2003 Author Posted July 10, 2003 Originally posted by Sayonara³ Ages ago when Focus magazine was new and less crappy, I sent that in to the questions page. They printed it with a picture of an iceberg and everything \o/ w00t \o/ way to go, Sayonara
Sayonara Posted July 10, 2003 Posted July 10, 2003 If the Antartic cap melted levels would rise, because the vast majority of the ice there is on a land continent. The ice at the Arctic pole is basically just floating about, so you might as well consider it to be part of the oceans.
Kettle Posted July 10, 2003 Author Posted July 10, 2003 Aha Thanks Btw - am I okay asking stuff like this? I mean, are n00bs with no grounding in science (but a huge fascination with it) welcome to post idiotic questions everywhere or are these forums for serious discussion between people with degrees in Cosmology etc? Maybe it might be worth having a forum subsection in each group devoted to Q&As - where someone can ask a question and people can suggest answers - much like you get in the back of magazines
Sayonara Posted July 10, 2003 Posted July 10, 2003 Originally posted by Kettle w00t \o/ way to go, Sayonara Go team :banana:!
JaKiri Posted July 10, 2003 Posted July 10, 2003 Originally posted by Sayonara³ If the Antartic cap melted levels would rise, because the vast majority of the ice there is on a land continent. The ice at the Arctic pole is basically just floating about, so you might as well consider it to be part of the oceans. Oi, stop giving things I said in the 2nd post in the thread as new information
Sayonara Posted July 10, 2003 Posted July 10, 2003 Originally posted by MrL_JaKiri Oi, stop giving things I said in the 2nd post in the thread as new information I think I communicated it better
Kettle Posted July 10, 2003 Author Posted July 10, 2003 It never hurts to have a few different perspectives for an explanation - makes it easier to understand and corroborates the information
rdjon Posted July 21, 2003 Posted July 21, 2003 The greenland ice sheet is on land though (and near the north pole, so is usually included in the north "Ice Sheet"). If this melted global sea levels would raise by 7m.
atinymonkey Posted July 22, 2003 Posted July 22, 2003 Um. Greenland has no icesheet. Icebergs and glaciers, but no icesheet.
rdjon Posted July 24, 2003 Posted July 24, 2003 Odd then that scientists have been observing it by satellite and have spent 7 years drilling through 3km of ice there then. Big, thick glacier at 3km BBC News
Giles Posted July 25, 2003 Posted July 25, 2003 The idea that recent changes in temperature could be attributed to the ending of an ice age has mostly been dismissed. Temperatures should be going up, but they should not be going up as fast as they have been. This is largely down to more comprehensive and accurate temperature data, but also partly down to the fact that temperature is not the only measure of the state of the climate. Global temperature averages conceal local effects, which will depend on local eco- and weather systems. Heat energy which melts ice, for example, doesn't make the air warmer at the same time. Furthermore, from recent changes in the behaviour of phenomena like el nino, it is pretty clear something is up.
atinymonkey Posted July 25, 2003 Posted July 25, 2003 Originally posted by rdjon Odd then that scientists have been observing it by satellite and have spent 7 years drilling through 3km of ice there then. Big, thick glacier at 3km BBC News Ok, I was wrong. There is an ice sheet. Quite right too. But I'm not convinced 50 billion tons of water would increase the global sea levels by 7m. Plus Greenland is actually a basin, so the increase would not be that much. However, you proved me wrong before.
daisy Posted July 25, 2003 Posted July 25, 2003 I seem to remember from dim amd distant undergrad days that we are in a "super-interglacial" period and that we are supposedly a few thousand years overdue for a new ice-age? I seem to remember something about ice-ages being separated by approx. 10,000 year interglacials...or am I wrong? Don't rush out and by your thermals just yet.
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