If the polar ice caps melts it shouldn't cause the sea level to rise.

[alchemy]

Ok we know that global warming is a fact and it can cause the polar ice caps to melt. But my question is this, isn't the polar ice caps just a giant block of ice that sits on top of the ocean? So even if it melts its shouldn’t cause the sea level to rise a lot.

Why? Because if u take a glass of water and put a ice cube in it cause the water level to rise, however after the ice have melted the water level stays the same. So if the polar ice caps is just a giant ice block that set onto of the ocean doesn't that mean even if it melts it shouldn’t cause the sea level to rise?

Maybe somebody has mentioned this before but i can't find it anywhere.

So am i right???

[Martin]

Greenland and Antarctic ice sit up on land

[alchemy]

i know that but i am talking about the polar ice cap

[Glider]

This planet has two poles. The Arctic and the Antarctic. In your original post, you state that global warming can cause the polar ice caps to melt, i.e. both of them.

[MattC]

I believe I heard Rush Limbaugh offer that same line of reasoning in one of his diatribes. According to him, environmentalists were stupid to worry about sea level rises - for this same reason. It's true, too - reducing the amount of ice in the north pole (over the ocean) will not raise sea levels. Yet, no one with any knowledge of the matter worries about this - instead, the focus is on Antarctica (the south-pole continent that is covered with a slab of ice that is miles thick), Greenland, and various glaciers.

[Aardvark]

. But my question is this, isn't the polar ice caps just a giant block of ice that sits on top of the ocean?

 

Not quite. There is a giant block of ice floating over the North Pole. However over the South Pole the ice is on land.

 

So even if it melts its shouldn’t cause the sea level to rise a lot.

 

Unfortunately not. If the ice melts in the South Polar region then the water will run off the land into the sea so raising sea levels

 

 

So am i right???

 

In the idea that floating ice won't significantly change sea levels if it melts, yes. Unfortunately, most polar ice is not floating on the ocean, it is on land. So rising sea levels are a concern.

[swansont]

The antarctic ice cap is much larger than the arctic, and since Greenland is mostly above the arctic circle I don't see why it shouldn't be counted. We're not talking about the infinitesimal amount of ice located precisely at the pole, are we?

 

There is a secondary effect to the warming. Water's density is temperature dependent. As it warms above 4 C, (where its density is largest) it expands, which also contributes to rising ocean levels.

[Dak]

quick question: as ice takes up more volume than water, and as icebergs are mostly underwater, wouldn't a total melting of all icebergs actually cause a drop in sea levels?

[swansont]

quick question: as ice takes up more volume than water, and as icebergs are mostly underwater, wouldn't a total melting of all icebergs actually cause a drop in sea levels?

 

The extra volume they take up is above the water. They displace water equal to their own mass which is why they float, and it all cancels. (you may now either say "Eureka!" or look up Archimedes' principle)

[Dak]

The extra volume they take up is above the water. They displace water equal to their own mass which is why they float, and it all cancels. (you may now either say "Eureka!" or look up Archimedes' principle)

 

hmm... the masses of the iceberg and the water displased are (obviously) identicle, sooo.... given that icebergs are made of water, the iceberg can only fit an amount of itself equal to the volume of the water from which it is created into the water? aaaaaaaaaaand, the same is true of the water that would result from melting the iceberg, hence there will be no more nor less displacement if the iceberg is melted?

 

then, alchemy was sort of right: melting ice-caps, in and of themselves, dont directly matter atall re: sea levels?

 

alchemy i've heard the following argued: ice is reflective, so bounses back alot of heat from the sun. melting ice en-mass will make the earth adsorb more heat, and so will amplify global warming, and thus any other effects (eg, swansonts water-expansion), so melting ice caps may indirectly effect water-levels by making the world heat up more; however, i heard that argued of all the large bodies of ice on earth -- i've no idea wether the amount of ice located just in ice-bergs is enough to have a significant reflective-cooling effect.

[timo]

hmm... the masses of the iceberg and the water displased are (obviously) identicle' date=' sooo.... given that icebergs are made of water, the iceberg can only fit an amount of itself equal to the volume of the water from which it is created into the water? aaaaaaaaaaand, the same is true of the water that would result from melting the iceberg, hence there will be no more nor less displacement if the iceberg is melted?

 

then, alchemy was right: melting ice-caps, in and of themselves, dont matter atall re: sea levels?[/quote']

Entry test passed, you may now proceed to post #2

 

@vv : It´s a neat thing and in fact the question "how does the water level in a soft drink change when the ice melts" is quite popular in tv shows and such. I remember we had a similar question in out first homework assignement when I started to study physics.

[Dak]

^

 

i just wanted to quickly say that i'm actually quite chuffed that i grasped that

 

me and phisics are not usually on speaking terms.

 

*wanders off feeling happy*

[swansont]

hmm... the masses of the iceberg and the water displased are (obviously) identicle' date=' sooo.... given that icebergs are made of water, the iceberg can only fit an amount of itself equal to the volume of the water from which it is created into the water? aaaaaaaaaaand, the same is true of the water that would result from melting the iceberg, hence there will be no more nor less displacement if the iceberg is melted?

 

then, alchemy was sort of right: melting ice-caps, in and of themselves, dont directly matter atall re: sea levels?

 

[/quote']

 

 

melting icebergs (i.e. floating chunks of ice) don't matter for this reason, and you can view much of the arctic icecap to be just one big iceberg. But the antarctic cap is not floating, it's on land, which has already been pointed out several times, so it does contribute. And since it's the larger icecap, it matters a great deal.

[DrCloud]

As noted, floating ice, when it melts, won't raise the level of the water in which it's floating, whether that water be in a glass or in the ocean. In the ocean, this stuff is generally called sea ice, and getting its behavior right in climate models is quite the trick. There is a fairly large group of people who have made it their careers to do so.

 

Now, not all ice that appears to be on the ocean is floating. Some of the large Antarctic glaciers that flow to the sea are, in fact, grounded offshore, so their height above sea level is greater than it would be if they were floating. Thus, if they melt (or break off into floating icebergs), they'd raise sea level.

 

All ice that melts permanently off continents (and isn't replaced by new snow) and runs into the ocean will raise sea level.

 

Finally, one of the strongest and most interesting feedback processes in the climate system -- because it's a positive feedback -- is the reflectivity of snow and ice. It's positive because it's reinforcing: more ice implies more solar energy reflected to space implies a cooler planet implies more ice implies... (and it works the other way, too). HPH

[YT2095]

IIRC this was the least of the problems, when they melt the salinity of the oceans decrease and there goes the Gulf Stream

 

Ice age

[DrCloud]

^^ Not exactly.

 

The degree to which the circulation of the North Atlantic would change with (for example) the melting of the polar ice isn't fully understood. While there is some indication that the thermohaline circulation (what's also known as the "global conveyer belt") might be altered, the Gulf Stream is also part of the wind-driven circulation in the North Atlantic. So unless the atmosphere's current circulation changed beyond recognition, there would still be some poleward transport of heat by the oceans.

 

Generally speaking, this part of the overall problem is a negative feedback loop, because when a temperature gradient builds up in a fluid (because one of the existing transport processes breaks down) instabilities develop to get that heat moving. Ultimately, that's why the atmosphere circulates. HPH

[Edtharan]

Here is another problem with the melting of the ice on Antarctica. The ices has a lot of weight, and this weight is pushing the continent of Antarctica downwards. When the Ice melts this will allow Antarctica to rise, along with the seabed around it (continental shelf). This riseing of the seabed will also displace water and contribute to a further rise in sea levels.

[bascule]

Finally, one of the strongest and most interesting feedback processes in the climate system -- because it's a positive feedback -- is the reflectivity of snow and ice. It's positive because it's reinforcing: more ice implies more solar energy reflected to space implies a cooler planet implies more ice implies... (and it works the other way, too). HPH

 

Yup, and that's one of the many feedback loops near the tipping point in the climate system right now. The highly reflective surface albedo of ice is being replaced by the highly absorbant surface albedo of sea water.

 

Melting sea ice doesn't matter, as far as sea level goes. Glaciers, on the other hand...

[YT2095]

DrCloud; That`s the wording I was after, the Atlantic Conveyer Thnx

 

also another Problem that will occur (and has done already on a smaller scale) is that Large sections of this ice will simply fall off into the water creating a massive tidal wave(s).

[DrCloud]

^^ The grounded glaciers in Antarctica have calved state-sized ice floes (well, the size of those little northeastern states, anyway) without too much splash, at least on a global scale.

 

Tsunamis are more effectively generated by undersea earthquakes in which significant crustal displacements occur over tens of kilometers. On the other hand, it wouldn't do to be on a ship close to some of this ice action. HPH

[YT2095]

there was one up north a few years ago, a massive chunk of ice fell off and plopped into the drink, it was the equiv of a few Kiloton nuclear device being set off underwater.

some of the "potentials" are much larger than this and waiting to happen (like an avalanche).

[silverslith]

there was one up north a few years ago, a massive chunk of ice fell off and plopped into the drink, it was the equiv of a few Kiloton nuclear device being set off underwater.

some of the "potentials" are much larger than this and waiting to happen (like an avalanche).

 

you could well be right. The calving of a 70kmlong x 20km wide x 2km thick iceberg from floating shelves is not so spectacular cause its already floating. A chunk like this falling off a piece of land would be bigger than the volcanic island underwater landslides that are supposed to have made mega tsunami in the past. Oh well, I live at 2000 ft so why should I care.

[CPL.Luke]

actually melting sea ice does make somewhat of a diference, if you note the ice is composed of freshwater (the salt gets forzen out), and the sea water is composed of salt water which has a higher density than water, so when the ice melts there is some increase in water levels.

[outdoorszee]

I joined this site after reading very insightful feedback as to the "rising sea level VS melting polar ice" theory that gets bantered around.

 

After reading a few posts I now understand the land based and water based iced masses and their effects. Funny, that I had to dig to really understand (this site helped).

 

So, my question is this............ given that the Artic (floating ice) and Antarctic/Greenland (land based ice)...hope I have this right???

What is the difference in sizes of the respective ice masses? ie. Covers a certain area, with a certain thickness??

 

I know a lot of people understand an issue much more clearly with visualization (me included). So, thought that some wise soul could help me understand.

 

Thanks for the assistance...

 

D

[insane_alien]

okay, imagine a continent about the size of north america covered in a slab of ice about 2 and a half miles thick. thats how much ice we're talking about for land based ice(and hen it melts the land is going to rise up a bit because of the great weight thats been taken off it, it happened in the UK after the iceage, it'll happen in antartica) the sea based ice is considerably less but still a heck of a lot of ice.