Random science question...

[lawrocket 3]

I'm no scientist, but I am curious about something.

Assuming, for the sake of argument, the earth's mean temperature rises a couple of degrees in the next century. (This is only an assumption).

I note that this increase in temperature will not melt the Antarctic ice cap, since the Antarctic temperatures are too low for a couple of degrees to melt the ice on its land masses.

But, assuming that it melts a large amount of the northern ice cap, the question is this:

How will that raise the sea level? The ice is floating on water, right? And since the ice displaces water equal to its weight (water), it should even out to a zero net increase.

How, then, is it, that people argue that the sea level will rise and wash away Los Angeles and San Francisco if the ice cap starts melting?

My wife is hotter than your wife.

[TribalTalon 0]

its wishful thinking

[turtlespeed 226]

My guess would be that it would melt a large enough amount to cause run-off into the ocean, but the scale would be unable to support what they assume. It would also cause it to rain more vs. snow which allows for more water.

Expecially when you consider that Ice Expands when it is frozen.

But I am not a scientist and I am assuming as well, and i am Probably wrong.

I'm not usually into the whole 3-way thing, but you got me a little excited with that. - Skymama
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[Nightingale 0]

Ice floats.

A good part of that ice is ABOVE water. if that mass becomes part of the water, you have a rise in ocean levels.

[lawrocket 3]

Ah, yes, nightingale. But, ice floats in my beverages, too, and when the ice melts it doesn't overflow them.

I thought that the iceberg would displace the saem weight of water as the weight of the iceberg. That means that if it wieghed a million tons, a million tons of water would be displaced by it, anyway. Then, when the million tons melts, it doesn't displace it anymore, which results in a net change in sea level of exactly zero.

My wife is hotter than your wife.

[jtval 0]

actually the part you see avoe water is minuscule to what is UNDER it.

If the temp rose a few degrees there would probly be a SMALL change and the ice caps would melt a bit but not completely.

water would rise i small amount but I dont think it would be anything like youd see in a movie. LOL

this would ,by your scenerio, take 100 years

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[jtval 0]

not necc true...

if you put alot of water in the glass and then put aafew icecubes in the water to make it fill the glass totally that would change your outcome,.

the part of the ice that float above the glass would melt and eventually cause overflow

EDIT-
Doh--you deleted that reply.

lets say you take an 8 oz glass fill it with 6 oz water and add 4 oz of icecube. know though Im not sure of specific measurements, there would bepart of the ice cube above the water. which would be fill to the very top.
that extra 4 oz would melt and spill out. ect.

for those who are sticklers- I know that the water would spill when you put the ice in b/c in my thoery then 1/2 the cube is floating...just imagine lol

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[cop 0]

Öööh, ice really floats...

But I'm ready to change my opinion if Malmi airport in Helsinki will survive...

"You can call me Mike"

[indyz 1]

Quote

Ice floats.

A good part of that ice is ABOVE water. if that mass becomes part of the water, you have a rise in ocean levels.

Uh, no. The floating ice displaces an equal mass of water. Here's the experiment: Put a bunch of icecubes in a cup. Fill the cup with water so that it is completely full. Let the ice melt. I bet the water level in the cup will remain exactly the same, and that no water will have spilled over.

[billvon 3,121]

>How will that raise the sea level? The ice is floating on water, right?

Much of the ice they refer to is in glaciers and snowpacks on land. You're right in that melting sea ice will not change the sea level. (Which is fortunate, since a lot of polar ice melts and refreezes every year.)

In addition, water expands when it gets warmer. That alone will cause some sea level change.

>How, then, is it, that people argue that the sea level will rise and
> wash away Los Angeles and San Francisco if the ice cap starts melting?

Not so much wash away as cause problems for. A 10mm change in sea level will generally cause the shore to retreat by about a meter. In many places, losing 10 meters of coast will cause loss of barrier beaches, critical to protecting against storms. Also, seawater intrusion into aquifers will cause big problems for cities and farms that rely on local water tables.

[eeneR 3]

ah yes, but he is refering to ice that goes above the top of the glass and water line...they yes if there is enough it could overflow...

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[billvon 3,121]

>ah yes, but he is refering to ice that goes above the top of the glass
>and water line...they yes if there is enough it could overflow...

If you really pack the glass so the ice is sitting on the bottom of the glass, then you're right - it could overflow. Same thing with ocean ice. If a floating iceberg melts it won't change the sea level. But if, say, the Ross ice shelf melts (much of which is sitting on the ground due to its thickness) then sea level would indeed rise.

[lawrocket 3]

No, but the ice on top of the glass displaces an amount of water equal to the weight of the ice, so it would not spill over.

And I hadn't thought about what bill mentioned with the natural expansion of water as it warms. Interesting point.

My wife is hotter than your wife.

[pilotdave 0]

Definitely no expert on the subject, but I remember when the movie water world came out, I heard predictions that if all the polar ice melted, the oceans would actually rise about 6 inches. No idea if that's even close to correct or not.

Dave

[airgord 1]

Surfin' in Eloy!!!!!!!!!!!!!

[billvon 3,121]

>I heard predictions that if all the polar ice melted, the oceans would
>actually rise about 6 inches.

If ALL the polar ice melted (very unlikely) sea levels would rise about 250 feet.

[Skypup 0]

Edited to remove repitition of things Bill posted.

What I would be more worried about is the change in global weather patterns based on a few degrees of temperature change. (Not to say that it's not a natural occurance but we are changing the rate that this occurs. )

ie. The typical weather pattern for your area moving north or south especially around the 30 and 60 degree latitudes. Which in those areas can make the seasonal variations milder or more extreme. (Depending on alot of factors in your area)

El nino and La nina events becoming more extreme.
Late winters etc.

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[jtval 0]

but would we still be able to skydive? LOL

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[riddler 0]

You don't have to worry much. Most water-ice displacement isn't going to make ocean levels rise considerably.

http://www.howstuffworks.com/question473.htm

Also, it's not really easy to understand - I'm going back to plate tectonics from College here - but a large number of well-respected geologists believe that large landmasses (the size of continents) also "float" to some degree. It's not conclusive, but there's a certain amount of water content in the layer between the hot magma of the core and the landmass on the surface. The landmass movement is primarily effected by geothermal energy, but there is also a certain amount of "continental drift" that is caused by the floating action of land over water.

Trapped on the surface of a sphere. XKCD

[jtval 0]

didnt hit the link yet...but if continents float then how was Nevada once under water? LOL

it was once the part of the ocean floor. ( i dont know much abou nevada history but redrock is filled with fossils etc

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[rehmwa 2]

OK - then does everyone agree that a full glass with ice in it will -not- change levels when the ice melts?

There might be some other effects if the ice and the water aren't the exact same composition. The lack of change in water level in your drinking glass assumes the ice and the drink are made from the same material (i.e., they have the same density when in the same state). So when you run your experiment, don't put ice cubes into something thick like oil, or it will overflow when the ice melts.

Thus it follows that, if the ice is more pure than the ocean it floats in, the melting will add thinner water. This means it does add more volume (in it's liquid form) than the ocean it displaced (when in solid form). I don't know if this applies or not.

Changes in the ocean levels mostly comes from ice that breaks off of land and ends up in the ocean when it wasn't there before - so mechanism is really simple, (fill your glass completely full and then drop a new cube in it - you spill). Maybe some thermal expansion of the oceans themselves (this is from riddler's excellent link in case you don't read links.)

melting the north pole isn't the issue, it's the climate stuff that goes with it. But first, you have to explain how a small (perceived) rise in a century is anything but natural or cyclical variation as part of our environment's norms.

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[rehmwa 2]

Quote

didnt hit the link yet...but if continents float then how was Nevada once under water? LOL

it was once the part of the ocean floor. ( i dont know much abou nevada history but redrock is filled with fossils etc

They do say the continents 'float' on a mass of magma. OK, no problem there. But geologists also note the the seams between these 'geological' plates also leak (thus rising land mass and volcanos are born). So imagine an 'incredibly' slow boiling/roiling motion of the land where parts in one area are rising up and other areas are sinking down.

It's thought that the rockies represent new land (only hundreds of millions of years old) and nevada is adjacent, so it would be part of the rising portion of the earth's crust.

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Driving is a one dimensional activity - a monkey can do it - being proud of your driving abilities is like being proud of being able to put on pants

[riddler 0]

C'mon JT - you're making me go back 15 years to classes I was trying to sleep through I was forced to take Geology because my school was supposedly the best for Geology, or something like that, but I was only there for the engineering courses.

Parts of land rise and fall as well - you'll see this in Florida, where divergent faults, caused by the slow movement of the North American plate to the west, fall down. Plate convergence can cause parts of land to rise (which is what caused the Rocky Mountains). There are also parts of land that are below sea level but dry, although most have water (lakes) in them. The part that is now Colorado was once undersea as well, but it's not the small (state-sized) parts of land that float, it's the entire *plate* (continent) that floats.

As far as ice melting and causing sea levels to rise - melting icebergs (or ice cubes) don't change water levels - for that to happen, the polar continents would have to melt, which is unlilkely, even if the temperature over the entire planet increased a few degrees. I think it's human ego that makes us think we have more power than we do - even that we are changing the climate. I don't think anyone has proven to me that these changes are purely the result of human action. I'm much more inclined to think that these are natural cycles.

Trapped on the surface of a sphere. XKCD

[rehmwa 2]

Agreed. and that's 700 posts.

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Driving is a one dimensional activity - a monkey can do it - being proud of your driving abilities is like being proud of being able to put on pants

[harryskydives 0]

So it would not be a bad thing if we could surf in Eloy. But i suspect that if the planet was warmer a lot of the melted ice would become water vapor in the atmosphere and cause a lot more rain. Then the clouds and rain would cool off the planet and you would have more snow pack. So I am not bringing my surf board to the Xmas boogie.

PS I have been doing this experiment with Jack and ice for years. No conclusion more testing required.

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