# Quick question about global warming/sea ice etc... **URL:** \ **Category:** Factual Questions\ **Created:** [September 26, 2009, 5:59pm UTC](https://boards.straightdope.com/t/quick-question-about-global-warming-sea-ice-etc/511659 "2009-09-26T17:59:48Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Weston](https://avatars.discourse-cdn.com/v4/letter/w/8797f3/32.png) [@Weston](https://boards.straightdope.com/u/Weston)\ **Post date:** [September 26, 2009, 5:59pm UTC](https://boards.straightdope.com/t/quick-question-about-global-warming-sea-ice-etc/511659/1 "2009-09-26T17:59:48Z")
Some people say that if polar ice melts it will cause sea levels to rise. I don’t understand how this is possible. Can someone explain it please? ---
**Author:** ![jjimm](https://avatars.discourse-cdn.com/v4/letter/j/ba8739/32.png) [@jjimm](https://boards.straightdope.com/u/jjimm)\ **Post date:** [September 26, 2009, 6:03pm UTC](https://boards.straightdope.com/t/quick-question-about-global-warming-sea-ice-etc/511659/2 "2009-09-26T18:03:06Z")
It’s not about the ice that’s currently part of the frozen sea, which already has a net effect on sea levels - it’s about the ice that’s on land. A lot of the Arctic ice is on Canada, Greenland, Siberia, etc. and almost all of the Antarctic polar ice is on land, and thus doesn’t currently contribute to the sea level. If that melts and drains into the sea, it could raise sea levels significantly. ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [September 26, 2009, 6:25pm UTC](https://boards.straightdope.com/t/quick-question-about-global-warming-sea-ice-etc/511659/3 "2009-09-26T18:25:40Z")
There’s also concern that if some of the ice shelves surrounding Antarctica collapse, huge quantities of ice now being held inland by them may rapidly be dumped into the ocean. In some of the worst case scenerios, sea level rises several inches in as little as a few decades. ---
**Author:** ![Weston](https://avatars.discourse-cdn.com/v4/letter/w/8797f3/32.png) [@Weston](https://boards.straightdope.com/u/Weston)\ **Post date:** [September 26, 2009, 6:28pm UTC](https://boards.straightdope.com/t/quick-question-about-global-warming-sea-ice-etc/511659/4 "2009-09-26T18:28:02Z")
Ah, thanks very much guys. ---
**Author:** ![Polycarp](https://avatars.discourse-cdn.com/v4/letter/p/82dd89/32.png) [@Polycarp](https://boards.straightdope.com/u/Polycarp)\ **Post date:** [September 26, 2009, 6:45pm UTC](https://boards.straightdope.com/t/quick-question-about-global-warming-sea-ice-etc/511659/5 "2009-09-26T18:45:55Z")
Let’s add one more element to the equation. The Polar regions are “deserts” – arid in that they get very little precipitation; it’s just that what they get never goes away, so it builds up. This is true because the frigid air over them can hold very little moisture – what’s not there in the first place cannot fall. An ‘open’ Arctic – one with sea ice not a permanent fixture over at least large parts of the ocean area – shifts this picture. The air, while still cold, is not quite as frigid, and the air-water interface is capable of saturating the air with moisture, which then can be dumped on adjacent land as precipitation. Whether this leads to more, less, or the same amount of ice cover is not totally clear, but is definitely worth examining in light of the Beaufort Sea becoming at least seasonally open water. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [September 26, 2009, 6:48pm UTC](https://boards.straightdope.com/t/quick-question-about-global-warming-sea-ice-etc/511659/6 "2009-09-26T18:48:21Z")
It might be mentioned that the major factor in current sea level rise is not melting ice but thermal expansion of the oceans. As sea temperature rises, the water takes up more volume and thus sea level rises. While the effect of a few degrees rise is fairly small, taken over the enormous volume of the oceans it becomes significant. See [here](http://en.wikipedia.org/wiki/Current_sea_level_rise) ---
**Author:** ![Askance](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/askance/32/8281_2.png) [@Askance](https://boards.straightdope.com/u/Askance)\ **Post date:** [September 28, 2009, 1:16am UTC](https://boards.straightdope.com/t/quick-question-about-global-warming-sea-ice-etc/511659/7 "2009-09-28T01:16:57Z")
> [@Weston](#): > > Some people say that if polar ice melts it will cause sea levels to rise. No-one says that, that I am aware of, for the exact reason that has been covered already. Can you point to anywhere that claims this? [QUOTE=jjimm] A lot of the Arctic ice is on Canada, Greenland, Siberia, etc. and almost all of the Antarctic polar ice is on land, and thus doesn’t currently contribute to the sea level. If that melts and drains into the sea, it could raise sea levels significantly. [/QUOTE] Could? :dubious: