Polar Caps melt and volcanoes erupt - equal redistribution pressure

[scooter1971]

Great, I have your attention.

This basically involves all the ice on the polar caps melting and how that would affect the Earth when it comes to pressure redistribution. This of course would take a century and it would be a slow increase in volcano eruptions.

The Earth is oval shaped right now. Imagine all the weight of the polar ice caps gone and the weight is now evenly distributed. Equal distribution of weight allows greater pressure right? Would that also cause more pressure on the earth like evenly squeezing a ball? Then what? Volcanos?

Before any of us think this is silly maybe we should leave this to the scientists. I can't find a total approx weight on all of the ice caps and sheets. The highest number I did find was 70,000 million metric tons.

Thought provoking. Without doing the math how can anyone say it's impossible?

Before you are to quick write this off try considering a hypothosize on what would happen.

[geoguy]

As a geologist just one comment:

 

BALONEY

[scooter1971]

A few thoughts:

There are about 20 more volcanoes per year now than 50 years ago. http://www.volcano.si.edu/world/find_eruptions.cfm

 

Scientists: Prehistoric volcanoes heated Earth

http://www.cnn.com/2007/TECH/science/04/27/volcanoes.warming/index.html

 

If it takes 50 years to add 20 volcanoes, how many will it take to cause a planatary crisis?

[Sisyphus]

Your causal account doesn't make sense. "Equal distribution of weight allows greater pressure right?" No, it doesn't.

 

Also, even if that were the case, it can't be the cause of 20 more volcanoes in the last 50 years.

[foodchain]

"Isostasy is a term used in Geology to refer to the state of gravitational equilibrium between the Earth's lithosphere and asthenosphere such that the tectonic plates "float" at an elevation which depends on their thickness and density. It is invoked to explain how different topographic heights can exist at the Earth's surface. When a certain area of lithosphere reaches the state of isostasy, it is said to be in isostatic equilibrium. Certain areas (such as the Himalayas) are not in isostatic equilibrium, which has forced researchers to identify other reasons to explain their topographic heights (in the case of the Himalaya, by proposing that their elevation is being "propped-up" by the force of the impacting Indian plate)."

 

http://en.wikipedia.org/wiki/Isostatic

 

"But it's not nearly that simple. We know that the weight of the glacier ice was so great that it depressed the crust of the earth. The earth's crust behaves as an elastic structure and glaciologists know that, once the ice reaches a certain thickness, it depresses the crust about a foot for every three feet of ice (ice is roughly one third as dense as crustal rock). Normally, this deformation takes the form of gentle flexing and unflexing of the earth's crust, although it can be accompanied by faulting and reactivation of large regional structures. Thus, when the glacier melts, the crust returns (rebounds) to the position it had been before the ice advanced over it. It may do this smoothly and gradually, or the rebound may happen in quick jumps, resulting in earthquakes as faults form. I've seen quite fresh appearing 20-meter-high fault scarps in Lapland, where deglaciation occurred relatively recently and rapid rebound is currently taking place, spasmodically, as earthquakes."

 

http://www.nd.gov/ndgs/Rebound/Glacial%20Rebound.htm

[insane_alien]

is it just me or would the icecaps melting reduce the presure at the poles which would cause them to lift up by a few meters(possibly hundreds) which would, overall, lower the internal pressure of the earth?

[Spyman]

The Earth is oval shaped right now. Imagine all the weight of the polar ice caps gone and the weight is now evenly distributed.

It is not the weight of the ice that creates the oval shape, it is the rotation of Earth.

 

The rotation of the Earth creates the equatorial bulge so that the equatorial diameter is 43 km (27 mi) larger than the pole to pole diameter. http://en.wikipedia.org/wiki/Earth

[scooter1971]

I think I was trying got say to much under one thread. Great answers guys I really appreaciate the input. I'd like to separate what I was saying:

1) The shape of the Earth would likely change with the amount of weight on the caps. Sounds like foodchain explained this with the glacial rebound and possible earthquakes that can occur.

2) Volcanoes- Odd thing is there has been a gradual increase of volcanoes in the last 50 years, not sporadic either. A steady incline. I question if this gradual increase is tied to the gradual change in the climate. The climate change is tied to global warming. Leaves one to wonder if global warming is somehow causing an increase in volcano activity. What is globally affected by this? All I can think of is a change in caps. 70,000 million metric tons is nothing to sneeze at. I still can't find a source on total amount of weight we are talking about.

[scooter1971]

is it just me or would the icecaps melting reduce the presure at the poles which would cause them to lift up by a few meters(possibly hundreds) which would, overall, lower the internal pressure of the earth?

My point to the change in the shape of the Earth. Also, instead of pressing down on the Earth as if to make it oval via weight of the caps, what if you applied equal pressure around it? I ask only because of what I saw on mythbusters, season4. They duplicated the safe from the movie "The Score". Drill and insert a bomb to make it blow the door off, didn't work. What they did is filled it with water, lowered the bomb in a then blew the door clean off by over 20 feet. They gave it equal pressure on the door to accomplish this. I wonder how that example could apply to the pressure on the Earth changing.

[insane_alien]

shockwaves travelling through an incompressible liquid to blow a safe door off isn't quite the same thing.

 

as was said before the ice will only result in a few tens of meters change in height. nothing too big. the water will flow towards the equator where it will weigh less so overall there will be less pressure. this is the opposite of what causes vulcanism and is overall very tiny as they are more influenced by tectonic plate movement and currents in the mantle.

[geoguy]

The answer is No. This debate is akin to how does Santa get all those toys to all the kids in the world on Christmas Eve. If one wants to believe in Santa then one will keep oneself (scooter) in a state of polyanish detachment.

[Spyman]

I can't find a total approx weight on all of the ice caps and sheets. The highest number I did find was 70,000 million metric tons.

Ice has a density of 0.917 g/cm³ at 0 °C, whereas water has a density of 0.9998 g/cm³ at the same temperature.

http://en.wikipedia.org/wiki/Ice

 

Earth's north pole is covered by floating pack ice (sea ice) over the Arctic Ocean, the Arctic ice pack.

In addition, the Greenland ice sheet covers about 1.7 km² and contains about 2.6 million km³ of ice.

 

The land mass of the Earth's south pole, in Antarctica, is covered by the Antarctic ice sheet. It covers an area of almost 14 million km² and contains 25-30 million km³ of ice.

http://en.wikipedia.org/wiki/Polar_ice_cap

 

The Artic ice pack is floating so its impact from weight wouldn't change if it would melt.

http://en.wikipedia.org/wiki/Buoyancy

 

The Greenland Ice Sheet only contains 2.6 million km³ ice so it won't change my estimate much.

 

For a rough estimate lets say the Antartic has an average density of 0.917 g/cm³ and contains 30 million km³ of ice. That would give an weight of 27 510 million metric tons.

 

I don't know the density of Antartic ice, but it's probably not much different from Artic ice which is floating and thus has an density below 1 g/cm³. That would give an upper limit of 30 000 million metric tons.

[foodchain]

I think I was trying got say to much under one thread. Great answers guys I really appreaciate the input. I'd like to separate what I was saying:

1) The shape of the Earth would likely change with the amount of weight on the caps. Sounds like foodchain explained this with the glacial rebound and possible earthquakes that can occur.

2) Volcanoes- Odd thing is there has been a gradual increase of volcanoes in the last 50 years, not sporadic either. A steady incline. I question if this gradual increase is tied to the gradual change in the climate. The climate change is tied to global warming. Leaves one to wonder if global warming is somehow causing an increase in volcano activity. What is globally affected by this? All I can think of is a change in caps. 70,000 million metric tons is nothing to sneeze at. I still can't find a source on total amount of weight we are talking about.

 

I don’t know if I got it right, just throwing some terms out there really as I see connections possibly. The reality to me is water is one of the prime erosion agents really, so having the polar ice caps as free water alone will mean change in that regard, let alone what having that mass removed as a position will mean for tectonic forces and plate movement, to weather patterns and so much more really. I think such a large scale change overall to the planet as a system could only really spell a serious change from many different angels, but change none the less. If it will make volcanoes, well I could not say with any certainty either way save again having that much frozen water or mass now changed will surely mean change on a global scale.

[scooter1971]

You guys are so smart I love this! I'm a Strategist and I'm always troubleshooting so I think to much. I'm a layman in this area but I have crazy ideas I like to explore.

Thanks for the input; geoguy excluded.

[scooter1971]

I'm taking these thoughts and creating a new post called "connection to increased volcano activity and the caps melting".

[scooter1971]

There are about 20 more volcano eruptions per year now than 50 years ago. http://www.volcano.si.edu/world/find_eruptions.cfm

 

Scientists: Prehistoric volcanoes heated Earth

http://www.cnn.com/2007/TECH/science...ing/index.html

 

If it takes 50 years to add 20 volcano eruptions per year, how many years will it take to cause a planatary crisis? Is this the direction we're headed?

[ecoli]

I merged the two threads... there's really no need for both of them.

 

 

There's no evidence that there is a linear relationship between the two. Or any relationship at all, for that matter.

[JohnB]

scooter, you won't be able to establish a relationship. 50 years is not enough time, geologically speaking and accurate data for a longer time period just doesn't exist.

 

How many volcanic eruptions were there in 1756 for example? We just don't know. It would be like concluding that the Earth will freeze in 2 months because today's temperature was 1 degree lower than yesterdays. You need a longer baseline.

[scooter1971]

scooter, you won't be able to establish a relationship. 50 years is not enough time, geologically speaking and accurate data for a longer time period just doesn't exist.

 

How many volcanic eruptions were there in 1756 for example? We just don't know. It would be like concluding that the Earth will freeze in 2 months because today's temperature was 1 degree lower than yesterdays. You need a longer baseline.

I think there is a bit of evidence. I think we could be in a cycle that is repeating itself. I'm wondering of 20 more eruptions per year could be a contributiong factor to global warming.

http://www.cnn.com/2007/TECH/science/04/27/volcanoes.warming/index.html

I think Im referring to "The Volcano–Greenhouse Theory". I wonder if history could repeat itself. A volcanic cycle.

http://filebox.vt.edu/artsci/geology/mclean/Dinosaur_Volcano_Extinction/pages/studentv.html

[scooter1971]

I merged the two threads... there's really no need for both of them.

 

 

There's no evidence that there is a linear relationship between the two. Or any relationship at all, for that matter.

But what if? An area I don't think anyone has explored enough.