# If all the ice and snow all over the planet melts; where will the new coastline be? **URL:** \ **Category:** Factual Questions\ **Created:** [August 25, 2009, 4:15pm UTC](https://boards.straightdope.com/t/if-all-the-ice-and-snow-all-over-the-planet-melts-where-will-the-new-coastline-be/507643 "2009-08-25T16:15:01Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Henrichek](https://avatars.discourse-cdn.com/v4/letter/h/5daacb/32.png) [@Henrichek](https://boards.straightdope.com/u/Henrichek)\ **Post date:** [August 25, 2009, 9:41pm UTC](https://boards.straightdope.com/t/if-all-the-ice-and-snow-all-over-the-planet-melts-where-will-the-new-coastline-be/507643/21 "2009-08-25T21:41:02Z")
> [@Quartz](#): > > Because it’ not being depressed by the weight of the ice. Land rise is happening today, most visibly in Scandinavia At the Swedish High Coast, the land has risen several hundred meters since the ice sheet receded. For that reason it is a UNESCO World Heritage site. Quite a neat phenomenon. ---
**Author:** ![Qadgop\_the\_Mercotan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/qadgop_the_mercotan/32/83_2.png) [@Qadgop\_the\_Mercotan](https://boards.straightdope.com/u/Qadgop_the_Mercotan)\ **Post date:** [August 26, 2009, 2:16am UTC](https://boards.straightdope.com/t/if-all-the-ice-and-snow-all-over-the-planet-melts-where-will-the-new-coastline-be/507643/22 "2009-08-26T02:16:15Z")
> [@Sunspace](#): > > I’d be a little distrustful of those maps. The map of the hundred-metre rise has Lake Superior underwater, yet Wikipedia [says](http://en.wikipedia.org/wiki/Lake_superior) its surface is at 180 metres above present sea level. I agree, the map’s a bit inaccurate. Lake Michigan is currently at 176.5 meters above sea level, as is Lake Huron. Lake Erie is at 174 meters, and Lake Ontario at 74 meters. A 100 meter rise would only shorten the drop at Niagara falls by about 25 meters. Even a strong storm combined with tidal surge wouldn’t cause it to rise up into Lake Erie. Though I must admit that most of Lake Superior is already underwater, **Sunspace**. 😉 ---
**Author:** ![Ruby](https://avatars.discourse-cdn.com/v4/letter/r/13edae/32.png) [@Ruby](https://boards.straightdope.com/u/Ruby)\ **Post date:** [August 26, 2009, 2:36am UTC](https://boards.straightdope.com/t/if-all-the-ice-and-snow-all-over-the-planet-melts-where-will-the-new-coastline-be/507643/23 "2009-08-26T02:36:11Z")
Indiana and Illinois are pretty much gone and some coastal areas are unaffected…go figure. ---
**Author:** ![Michael\_of\_Lucan](https://avatars.discourse-cdn.com/v4/letter/m/dbc845/32.png) [@Michael\_of\_Lucan](https://boards.straightdope.com/u/Michael_of_Lucan)\ **Post date:** [August 26, 2009, 10:14am UTC](https://boards.straightdope.com/t/if-all-the-ice-and-snow-all-over-the-planet-melts-where-will-the-new-coastline-be/507643/24 "2009-08-26T10:14:20Z")
If the 100m map is right, damp will be a serious problem in my house here in Lucan. On the positive side, “view of the sea” may be a major selling point. I wonder if the OP was looking at the short term rather than the longer term. In the short term, even with heavy global warming, it seems unlikely that I will be treading water. Sea levels will rise, and will be a major problem for coastal communities in the short term. However, it is likely to happen slowly, not in a catastrophic way - although you may not agree if you have a house on the beach. There are indications that snowfall may actually increase over parts of Antarctica, which currently has a very low precipitation level. (Indeed, it is validly described as a desert for that reason.) Precipitation will rise because global warming will create more water vapour. So, that may partially counteract increased glacier calving at the Antarctic sea boundary as ice shelves continue to disappear. The overall expectation is that Antarctic ice will continue to decrease, but the intuitive expectation of gross melting in the medium term may not be accurate. I believe increased precipitation will not reduce melting rates in Greenland, but I am open to correction. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [August 26, 2009, 2:03pm UTC](https://boards.straightdope.com/t/if-all-the-ice-and-snow-all-over-the-planet-melts-where-will-the-new-coastline-be/507643/25 "2009-08-26T14:03:26Z")
I think some folks above are misinterpreting the 100 meter map as it relates to the Great Lakes. Lake Superior is shown just as it is today: full of water and with its current shorline. So is Lake Michigan & Huron. Having Erie connect to Ontario sounds wrong at first glance, but the western 3 are correct. They also show widespread flooding up the Mississippi valley to areas presently about 200m above sea level. Perhaps there is some expectation that when the current river flow of either the St. Lawrence or the Mississippi meets teh sea a lot further inland that there will be some back-up flooding of land. ---
**Author:** ![Michael\_of\_Lucan](https://avatars.discourse-cdn.com/v4/letter/m/dbc845/32.png) [@Michael\_of\_Lucan](https://boards.straightdope.com/u/Michael_of_Lucan)\ **Post date:** [August 26, 2009, 2:24pm UTC](https://boards.straightdope.com/t/if-all-the-ice-and-snow-all-over-the-planet-melts-where-will-the-new-coastline-be/507643/26 "2009-08-26T14:24:13Z")
Do we also need to note transfer of mass from the poles to the equator? As I understand it, the earth’s spin will result in a greater bulge of water at the equator, so that sea depth should increase more at lower latitudes. The earth’s rotational speed will also change. Does that matter? I can’t estimate the changes. Any suggestions? ---
**Author:** ![wolfman](https://avatars.discourse-cdn.com/v4/letter/w/a8b319/32.png) [@wolfman](https://boards.straightdope.com/u/wolfman)\ **Post date:** [August 26, 2009, 3:12pm UTC](https://boards.straightdope.com/t/if-all-the-ice-and-snow-all-over-the-planet-melts-where-will-the-new-coastline-be/507643/27 "2009-08-26T15:12:12Z")
> [@Elendil\_s\_Heir](#): > > Yikes! Goodbye Cuba, Florida and most of the American Southeast. Most of Australia split into two islands. Hardly anything left of the U.K. :eek: Japan survives better than I would have expected though. ---
**Author:** ![Mosier](https://avatars.discourse-cdn.com/v4/letter/m/7ea924/32.png) [@Mosier](https://boards.straightdope.com/u/Mosier)\ **Post date:** [August 26, 2009, 3:55pm UTC](https://boards.straightdope.com/t/if-all-the-ice-and-snow-all-over-the-planet-melts-where-will-the-new-coastline-be/507643/28 "2009-08-26T15:55:27Z")
> [@Michael\_of\_Lucan](#): > > The earth’s rotational speed will also change. Says who? ---
**Author:** ![Daylate](https://avatars.discourse-cdn.com/v4/letter/d/9dc877/32.png) [@Daylate](https://boards.straightdope.com/u/Daylate)\ **Post date:** [August 26, 2009, 3:55pm UTC](https://boards.straightdope.com/t/if-all-the-ice-and-snow-all-over-the-planet-melts-where-will-the-new-coastline-be/507643/29 "2009-08-26T15:55:28Z")
Was watching the History Channel last night, and they had a presentation on the origin of the Great Lakes - a very interesting show, I might add. One of the things they discussed was how the land rose after the ice sheet retreated. If I remember the number correctly - it was really late at night - the land around the Lakes has risen 1,800 feet since the sheet retreated around 12,000 years ago, and is still rising. At Toronto, the annual rise is being measured at around one inch per year. ---
**Author:** ![Sunspace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunspace/32/1250_2.png) [@Sunspace](https://boards.straightdope.com/u/Sunspace)\ **Post date:** [August 26, 2009, 4:33pm UTC](https://boards.straightdope.com/t/if-all-the-ice-and-snow-all-over-the-planet-melts-where-will-the-new-coastline-be/507643/30 "2009-08-26T16:33:23Z")
> [@Daylate](#): > > At Toronto, the annual rise is being measured at around one inch per year. See? I _knew_ we were going up in the world! ---
**Author:** ![Saint\_Cad](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/saint_cad/32/18907_2.png) [@Saint\_Cad](https://boards.straightdope.com/u/Saint_Cad)\ **Post date:** [August 26, 2009, 4:43pm UTC](https://boards.straightdope.com/t/if-all-the-ice-and-snow-all-over-the-planet-melts-where-will-the-new-coastline-be/507643/31 "2009-08-26T16:43:07Z")
> [@Zsofia](#): > > I’ve seen mugs that have the modern coastline on them, and when you fill them with hot liquid it turns into the global warming coastline. Where did you get it!!! Mrs. Cad needs one very badly! ---
**Author:** ![Captain\_Awesome](https://avatars.discourse-cdn.com/v4/letter/c/a698b9/32.png) [@Captain\_Awesome](https://boards.straightdope.com/u/Captain_Awesome)\ **Post date:** [August 26, 2009, 5:11pm UTC](https://boards.straightdope.com/t/if-all-the-ice-and-snow-all-over-the-planet-melts-where-will-the-new-coastline-be/507643/32 "2009-08-26T17:11:07Z")
> [@Michael\_of\_Lucan](#): > > In brief, the land masses of the earth float on liquid rock. To be technical, the asthenosphere (upper mantle involved in tectonics and isostasy) is better described as a plastic, ductile solid rather than liquid. Magma is a volumetrically tiny proportion, something like \<1% if I recall correctly. Global warming mugs are available from the [Unemployed Philosophers’ Guild](http://www.philosophersguild.com/index.lasso?page_mode=Product_Detail&cat=mugs&skip=0&item=0224&sortby=rank%20DESC). Incidentally I’ve got mine right in front of me now, and apparently I’m hosed, along with most of the UK. ---
**Author:** ![Captain\_Awesome](https://avatars.discourse-cdn.com/v4/letter/c/a698b9/32.png) [@Captain\_Awesome](https://boards.straightdope.com/u/Captain_Awesome)\ **Post date:** [August 26, 2009, 5:20pm UTC](https://boards.straightdope.com/t/if-all-the-ice-and-snow-all-over-the-planet-melts-where-will-the-new-coastline-be/507643/33 "2009-08-26T17:20:03Z")
ETA: The instructional [video](http://www.youtube.com/watch?v=ipfVaHoakqc&feature=player_embedded), for the aforementioned mug, is worth watching too. ---
**Author:** ![Mama\_Zappa](https://avatars.discourse-cdn.com/v4/letter/m/71e660/32.png) [@Mama\_Zappa](https://boards.straightdope.com/u/Mama_Zappa)\ **Post date:** [August 26, 2009, 5:29pm UTC](https://boards.straightdope.com/t/if-all-the-ice-and-snow-all-over-the-planet-melts-where-will-the-new-coastline-be/507643/34 "2009-08-26T17:29:58Z")
> [@Saint\_Cad](#): > > Where did you get it!!! > Mrs. Cad needs one very badly! I think my son got his either at a Smithsonian museum shop, or at Union Station. Not terribly useful info if you’re not in the DC area, of course. Here’s one online source: > **[Climate Change Mug - Caution Hot](https://www.wackyplanet.com/products/climate-change-mug-caution-hot)** > > Climate change mug that reads CAUTION HOT – The Planet, Silly. Not the Coffee. Perfect eco gift for environmentalists, and anyone who loves activist caffeine. ---
**Author:** ![Michael\_of\_Lucan](https://avatars.discourse-cdn.com/v4/letter/m/dbc845/32.png) [@Michael\_of\_Lucan](https://boards.straightdope.com/u/Michael_of_Lucan)\ **Post date:** [August 26, 2009, 6:58pm UTC](https://boards.straightdope.com/t/if-all-the-ice-and-snow-all-over-the-planet-melts-where-will-the-new-coastline-be/507643/35 "2009-08-26T18:58:59Z")
> [@Mosier](#): > > Says who? Let me explain. The earth is rotating, and without gravity, stuff on it would be thrown off. However, with the effect of gravity, the rotation still makes the earth a bit more lumpy round the middle - like my belly these days. The earth’s an oblate spheroid, a flattened ball squashed down slightly at the poles, and wider at the equator. The sea is a liquid, so it has an even stronger tendency of this kind. If there were no continents, and if you could magically spread the sea out evenly over the earth, it would not stay that way. It would adjust so that it was slightly deeper over the equator than at the poles. I believe that effect would mean slightly more of the melted ice will end up at the equator. However, I’m open to correction if I’m talking horse sh#t. ---
**Author:** ![Michael\_of\_Lucan](https://avatars.discourse-cdn.com/v4/letter/m/dbc845/32.png) [@Michael\_of\_Lucan](https://boards.straightdope.com/u/Michael_of_Lucan)\ **Post date:** [August 26, 2009, 7:07pm UTC](https://boards.straightdope.com/t/if-all-the-ice-and-snow-all-over-the-planet-melts-where-will-the-new-coastline-be/507643/36 "2009-08-26T19:07:11Z")
Sorry, Mosier, left out the key point :smack: and too late to correct my last post. That means that the earth’s rotation will slow slightly. Think of what happens when a skater is spinning round. If he pulls in his arms, he spins faster. If he swings them out straight, he slows down. The effect of more mass at the equator and less at the poles would be to slow the earth’s rotation very slightly. It would be so slight that we won’t notice it, but we might have to adjust atomic clocks sooner to keep them in line with sidereal time. Quod Erat Demonstrandum. ---
**Author:** ![WarmNPrickly](https://avatars.discourse-cdn.com/v4/letter/w/d78d45/32.png) [@WarmNPrickly](https://boards.straightdope.com/u/WarmNPrickly)\ **Post date:** [August 26, 2009, 7:20pm UTC](https://boards.straightdope.com/t/if-all-the-ice-and-snow-all-over-the-planet-melts-where-will-the-new-coastline-be/507643/37 "2009-08-26T19:20:39Z")
If the melting of the glaciers is causing some land masses to rise, is the extra weight of the water causing the sea floor to sink? ---
**Author:** ![BlinkingDuck](https://avatars.discourse-cdn.com/v4/letter/b/eada6e/32.png) [@BlinkingDuck](https://boards.straightdope.com/u/BlinkingDuck)\ **Post date:** [August 26, 2009, 7:26pm UTC](https://boards.straightdope.com/t/if-all-the-ice-and-snow-all-over-the-planet-melts-where-will-the-new-coastline-be/507643/38 "2009-08-26T19:26:41Z")
> [@Elendil\_s\_Heir](#): > > Yikes! Goodbye Cuba, Florida and most of the American Southeast. Most of Australia split into two islands. Hardly anything left of the U.K. :eek: Europe, Russia and China look particular screwed. U.S. doesn’t look as bad off. Texas gets hit but that doesn’t count as it’s like a whole other country. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [August 26, 2009, 7:42pm UTC](https://boards.straightdope.com/t/if-all-the-ice-and-snow-all-over-the-planet-melts-where-will-the-new-coastline-be/507643/39 "2009-08-26T19:42:37Z")
> [@](#): > > Where did you get it [continent-changing mug]!!! > Mrs. Cad needs one very badly! Way back when, I had a similar mug that I had gotten as a freebie for subscribing to _Science News_. Except mine turned from Pangaea to the modern continents. It was actually a pretty decent mug, but the thermal-changing pattern eventually faded permanently to the halfway point. Still, I only paid a dollar for it plus the trial subscription, so it was a deal. ---
**Author:** ![Polycarp](https://avatars.discourse-cdn.com/v4/letter/p/82dd89/32.png) [@Polycarp](https://boards.straightdope.com/u/Polycarp)\ **Post date:** [August 26, 2009, 8:36pm UTC](https://boards.straightdope.com/t/if-all-the-ice-and-snow-all-over-the-planet-melts-where-will-the-new-coastline-be/507643/40 "2009-08-26T20:36:59Z")
One thing I noted was that land below 100 meters elevation was shown as submerged – even if it did not connect to the ocean. Most notably, the Pannonian Plain (Hungary and Transylvania, with some surrounding lands) would probably end up like the Imperial Valley or the Dead Sea area – below sea level dry land, with salt lakes here and there. [Previous page](https://boards.straightdope.com/t/if-all-the-ice-and-snow-all-over-the-planet-melts-where-will-the-new-coastline-be/507643.md?page=1) [Next page](https://boards.straightdope.com/t/if-all-the-ice-and-snow-all-over-the-planet-melts-where-will-the-new-coastline-be/507643.md?page=3)