GENIUS FORUMS

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The melting of oceanic icebergs does not affect the level of the ocean. Only the melting of ice that resides on land can affect the level of the ocean.

To explain, ice is less dense than water. As ice turns into water it shrinks until it is the same density as water.

For example, in the case of an entire iceberg melting, shrinking compensates for the ice that was residing above sea level but is now in the ocean.


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True. What I'm concerned about is when the Arctic Shelf melts enough to collapse, which would not only raise the ocean's level, it would do so on one rather quick maneuver, and I suspect tidal waves would result.

My question which I can not seem to get an answer to is: Is there a maximum height to a tidal wave? If there essentially is not, the size of the tidal wave might result in the kind of flooding that has been depicted in many religions from around the world. Noah's Ark was one story, there was another - I believe from China where a female was credited with causing the waters to recede, I don't recall the rest off hand.
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Elizabeth Isabelle wrote:True. What I'm concerned about is when the Arctic Shelf melts enough to collapse, which would not only raise the ocean's level, it would do so on one rather quick maneuver, and I suspect tidal waves would result.

Are you suggesting there is a ginormous lump of ice supported above the ocean, or in a position where it could suddenly slide into the ocean?

I don't see this as likely, and therefore i do not see a tidal wave of problematic proportions as likely.

My question which I can not seem to get an answer to is: Is there a maximum height to a tidal wave? If there essentially is not, the size of the tidal wave might result in the kind of flooding that has been depicted in many religions from around the world. Noah's Ark was one story, there was another - I believe from China where a female was credited with causing the waters to recede, I don't recall the rest off hand.

Most tidal waves are actually relatively small in height when they are out to sea, though nevertheless pack a punch. When they enter shallow waters they get raised by the bed of the sea - and the peak height increases.


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Rhett Hamilton wrote:Are you suggesting there is a ginormous lump of ice supported above the ocean, or in a position where it could suddenly slide into the ocean?

Yes, that's pretty much it. Here has a picture of the breakup of the Larson Ice Shelf. You can see from the picture that a large chunk went at once. Now yes, they do call the ice shelves "floating" but they do not float in the same way an iceberg floats. An iceberg is entirely supported by water. so 90% of it is going to be under water. An ice shelf is supported by water and land. The ice in the water melts first, leaving much of it supported over the water - kind of like an ice bridge over the water. Once enough of the ice underneath melts that the weight of the bridge can not be supported by the land mass itself, kersplash - like dropping an enormous ice cube into the water.

According to this article released in December about an ice island breaking off one of Canada's ice shelves, scientists are realizing that they were wrong about the slow melting of the ice shelves, and that when they collapse they do so within an hour. This happened in August 2005, 10 days before the formation of Hurricane Katrina. Correlation is not causation and I don't see any way that the break could have been causative of Katrina, but I thought the timing was interesting.

From the article:

It broke clear from Ellesmere island, about 500 miles south of the North Pole, 16 months ago, triggering tremors so powerful they were picked up by earthquake monitors 155 miles away.

Here is a map of Ellesmere Island and here is a map of the Ayles Ice Shelf where this happened. Looking in the direction of where the splash would have gone, it would only have gone into the frozen north pole. Since it took scientists over a year to figure out that this chunk causing that much commotion on the Richter scales (because nobody lives up there), there is no way to know if a tidal wave occurred as a result.

Like you said and according to this article:

The breakup of peninsular ice shelves has little direct consequence for sea-level rise. However the shelves act as buttresses, or braking systems, for glaciers on the continent

This article illustrates the data on the land glacial ice flow after the collapse of the Larson B.

You may be right about no tidal waves, and I hope so. The sea pressures in Cape Town for the time period of the Larson B collapse do not appear to be of a significant variance (DHodges would be a better person to ask, though, on whether or not the variance was statistically significant) - but I'm not really sure that's the direction it would have gone. Here is a map of Larson B and here is a world map of Weddell Sea. Additionally, even if there were a tidal wave forming, it would have had to cross the oceanic conveyor belt up to 4 times. If the Ross Ice Shelf goes, it will only have to cross the conveyor belt twice (one warm side, one cold side) before hitting land, but even that much could be enough to disrupt it down to being non-damaging.
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Wave power machines take some of the energy out of waves.

I don't know what the efficiency of the new breed of wave-power machines is though.

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Tidal waves do happen. Last week I watched one of those programs, and there's this island just left of Africa, with two volcanoes, one exinct and one active. And the last time it went off, a geologist started studying it because there was an area where the land just fell several feet along a divide. So they figured out that this sometimes happens with volcanic islands, that there develops a huge unstable crack that gets bigger each time there is an eruption, having something to do with water temperature and pressure in the crack. They don't know when it'll go off again (last was the 1940's) and they don't know how many eruptions it will take to make the land chunk off - but when it does there will be a massive tidal wave headed toward the east coast of the United States. Apparently, it will affect hundreds of miles of coastland.

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-lolaus warns-
but when it does there will be a massive tidal wave headed toward the east coast of the United States. Apparently, it will affect hundreds of miles of coastland.


-tomas muses-
(in a non-terroristic way) - I'll settle for the District of Columbia, specifically, the seats of power.


Tomas (the tank)
VietNam veteran - 1971

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Not to worry, Tank, DC should be right in the middle. The Great Satan itself.

Iolaus,

I believe you're speaking about the Azores, a volcanic chain of islands off the coast of Portugal/Spain. If half of the island in question were to slide into the ocean, the east coast of America would be subject to tsunamis towering up to and above 450 feet tall.

Rhett, Elizabeth,

The biggest threat melting arctic ice poses is that of effecting the flow of heat throughout the earth. Being that water holds 1000 times more heat than air, the oceans themselves are the greatest conveyor of heat to the northern hemisphere. Basically, as water in the north Atlantic cools it also expands, forcing it upwards towards the surface. It continues southward along the European coast, down along to Africa and the equator, where it again heats up due to the Sun's energy. As it heats, it contracts, and turns into what we in America know as the Jet stream which flows northward along the eastern US. With the introduction of anomalous amounts of melting arctic ice, this whole system of energy conveyance is threatened with ultimately shutting down, leaving the north thrust into a mini ice-age.

There's more to it than that, and my facts are probably a bit off, but that's what I recall.

Sounds right to me. There was a doc on this recently that I failed to watch attentively.

With the introduction of anomalous amounts of melting arctic ice, this whole system of energy conveyance is threatened with ultimately shutting down, leaving the north thrust into a mini ice-age.

My question is, that being the case, do you think the mid to lower southern hemisphere will become even hotter. If the heat that would have gone to the far north, no longer does then it must remain in the lower northern and southern regions. So could one say that Ice ages are hemisphere centric - if the Northern part of the northern hemisphere goes into Ice age, then the rest of the world heats up even more.

Heat is a cause so it does not just disappear - without a caused change in atmosphere, no more heat will leave the earth into space than before the ice age, except with atmosphere changes, so it must go somewhere.

This could be very very dire for Australia and Africa and would explain why it is appears to be a parched country regardless of ice ages. Perhaps the heat from a northern ice age caused the early African homo sapiens to move north?

Actually, from listening to the Al Gore movie, global warming is supposed to cause the areas near the equator to become more temperate. I take the recent weather here as confirmation, as it didn't freeze here last winter like it normally does one or two nights in the winter, but also we only usually have "sweater week" as far as cold in the winter, but this year we had quite a bit of sweater weather, and despite it being the end of May, we still frequently get cool weather at night. This is completely unusual.

Jamesh wrote:Heat is a cause so it does not just disappear - without a caused change in atmosphere, no more heat will leave the earth into space than before the ice age, except with atmosphere changes, so it must go somewhere.

Ice is also a lot more reflective than earth or trees.

Don't listen to Al Gore. He's a pothead.

A major cause, if not THE major cause, of the regional warming of certain areas on the earth's surface (yeah, that's right its not 'global' but regional, and its not up in the atmosphere either, but on the ground) is the dirty soot from coal and other industry - of which the US is a minor culprit and China and Asia the major ones. And by the way, China puts out nearly the same CO2 that we do - but the poor babies can't be expected to implement any costly pollution reduction measures. The pollution reduction measures they need to implement would be to reduct SOOT emissions. Soot cannot travel around the world like CO2 does, it can only fall within a few thousand miles at best. That's why its making the snow and ice melt in the northern hemisphere. It darkens the snow. And as it causes the snow to reflect less heat and absorb more of it, and as that causes more melting - then the soot on the snow becomes even more concentrated, i.e., it creates a positive feedback loop leading to more warming.

BMcGilly07 wrote:The biggest threat melting arctic ice poses is that of effecting the flow of heat throughout the earth. Being that water holds 1000 times more heat than air, the oceans themselves are the greatest conveyor of heat to the northern hemisphere. Basically, as water in the north Atlantic cools it also expands, forcing it upwards towards the surface. It continues southward along the European coast, down along to Africa and the equator, where it again heats up due to the Sun's energy. As it heats, it contracts, and turns into what we in America know as the Jet stream which flows northward along the eastern US. With the introduction of anomalous amounts of melting arctic ice, this whole system of energy conveyance is threatened with ultimately shutting down, leaving the north thrust into a mini ice-age.

There's more to it than that, and my facts are probably a bit off, but that's what I recall.

Hi Bryan,

As far as i understand H2O's property of expanding during icing is uncommon. Anyway, this property should not be confused with liquid H2O. Water just above 0 Degrees Celcius (freezing point) is most dense then as temperature increases it becomes less dense (though not by much, i think less than 1% or thereabouts) until it reaches 100 Degrees Celcius (boiling point). I note that it's easier to understand solid, liquid and gaseous states and the transition between them using particle theory.

Water being relatively dense harbours a lot of energy in whatever temperature it has above absolute zero (zero Kelvin).


**Edited 24th May**