Rise of sea levels is 'the greatest lie ever told'

[Ophiolite]

It DOESN'T SHRINK at all.

I am puzzled by this statement. If the temperature of the interior falls, then the expectation would be a reduction in volume. Phase changes could counteract this tendency, but I cannot think of any postulated phase change effecting mantle or core that would increase volume. What did you have in mind?

The Crust FLOATS because it is less dense.

The crust certainly does not float. The mantle is solid and the crust can hardly float on a solid. You shouldn't confuse educational metaphors with reality.

Thus the slowly cooling earth is getting ever so slightly larger (but ever so slightly)

:shrug:

 

[adoucette]

The crust floats on top of the mantle.

Both of these types of crust are less dense than the rock found in the underlying upper mantle layer.

http://www.physicalgeography.net/fundamentals/10h.html

 

[adoucette]

You need to make up your mind. Is the body of the Earth cooling or heating?

The Earth doesn't have a "body".

The Core of the earth is very very very slowly cooling, at ~ 100 C per Billion years or so.

The Surface of the earth, including the oceans and the atmosphere is very slowly warming.

I've never said anything different than that.

Arthur

 

[Robittybob1]

The Earth doesn't have a "body".

The Core of the earth is very very very slowly cooling, at ~ 100 C per Billion years or so.

The Surface of the earth, including the oceans and the atmosphere is very slowly warming.

I've never said anything different than that.

Arthur

The Earth is a planet
Planet = planetary body
Earth = planetary body
so the Earth is a body
and has a body and a skin ( OK they have other more technical terms as well) but the body is the major volume/mass of it.

The surface warming is probably the action of the Sun and greenhouse effect is that right?

 

[Robittybob1]

Another important factor in the continual rise of the oceans (now that the Expanding Earth has stopped ) is the amount of silt filling in the ocean. The average dept of the silt on the sea floor is 500 m. (now I have lost that reference sorry, but that was the best estimate from years ago.) that varied from several kms thick right down to zero at the sea floor mid-ocean ridges (expansion joints?).

So the more sediment is washed off the continental plates this must have some effect tending to raising the level of the oceans but I have never heard this being discussed.

 

[adoucette]

The surface warming is probably the action of the Sun and greenhouse effect is that right?

Yes, though there are other factors as well, like the amount of clouds which can change the albedo, the amount of high soot particles, land use changes etc, etc, so any simply summary like yours is only correct in the general sense. If you want to actually understand it at a deeper level I'd suggest reading the IPCC reports, "The Physical Science Basis"

http://www.ipcc.ch/publications_and_data/ar4/wg1/en/contents.html

 

[adoucette]

Another important factor in the continual rise of the oceans (now that the Expanding Earth has stopped ) is the amount of silt filling in the ocean. The average dept of the silt on the sea floor is 500 m. (now I have lost that reference sorry, but that was the best estimate from years ago.) that varied from several kms thick right down to zero at the sea floor mid-ocean ridges (expansion joints?).

So the more sediment is washed off the continental plates this must have some effect tending to raising the level of the oceans but I have never heard this being discussed.

Not sure what the average is, but just using the Mark 1 eyeball, I wouldn't be surprised if the average depth was about 500 m.

http://www.ngdc.noaa.gov/mgg/image/sedthick9.jpg

But the other thing you will notice is that virtually all of the deep sediments are on the Continental shelfs

According to this: These shelf sediments accumulate at an average rate of 30 cm/1000 years

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

Continental shelves and slopes account for about 15 percent of the oceans area.

http://www.waterencyclopedia.com/Oc-Po/Ocean-Floor-Bathymetry.html#ixzz1dySqLkFU

At 30 cm/1000 years for the shelf and slope area, that equals 4.5 cm/1000 years for the entire ocean, which allowing for a little gain outside the shelf area itself, is about 5 mm average accumulation per century (or about 1/4 inch).

Arthur

 

[fiction_is_science]

Well, I've been going to a place where I catch a lot of crabs with family. Yes with bare hands (Oh wait, with gloves. haha). We keep walking towards the sea until the sea level reaches my lower chest. I remember like a couple of years ago, we used to be able to get past some sort of buoy and the water was just on my waist line. Now when we reach the buoy, I can't seem to go further as the sea level is on my lower chest already. The buoy is fixed, my height has not changed and we always go out during low tide. I think sea level is increasing, but not by much. By no means will we witness lands being covered by sea, but if global warming continues, I'd say some lands will be a bit submerged into water in like 300 years or less. They say the polar ice caps are melting. If the sea level isn't increasing, where is all that water going right? I believe it is rising, just not to the extent where we will witness the consequences. Maybe 6 - 7 generations from now. At least that's how I see things.

 

[adoucette]

Well, I've been going to a place where I catch a lot of crabs with family. Yes with bare hands (Oh wait, with gloves. haha). We keep walking towards the sea until the sea level reaches my lower chest. I remember like a couple of years ago, we used to be able to get past some sort of buoy and the water was just on my waist line. Now when we reach the buoy, I can't seem to go further as the sea level is on my lower chest already. The buoy is fixed, my height has not changed and we always go out during low tide. I think sea level is increasing, but not by much. By no means will we witness lands being covered by sea, but if global warming continues, I'd say some lands will be a bit submerged into water in like 300 years or less. They say the polar ice caps are melting. If the sea level isn't increasing, where is all that water going right? I believe it is rising, just not to the extent where we will witness the consequences. Maybe 6 - 7 generations from now. At least that's how I see things.

Well any given location can have specific changes not at all associated with sea level change.
Indeed, in the US coast line, while most areas show the sea level going down, they don't to the same degree and we also have areas where the local sea level is going up.

Determining the Global Mean Sea Level and it's changes is not at all easy, and essentially can't be done just by walking out into the ocean each year from the same location. One contrary example would be that the land areas that were covered with glaciers in the last ice age are still rebounding from all that weight that was on them for so long (takes a real long time), and for those coastal areas the ocean appears to be falling.

For instance Stockholm:

Of course other areas have subduction zones off shore, and so they would see the sea as rising much faster than it actually is.

The net is that what we think we know is that the seas are rising a bit less than 3 mm per year and have been doing so for a while now, and will continue to do so into the future, and that rate will likely go up if the average temperature of the globe continues to rise.

http://www.aviso.oceanobs.com/filea...sl/MSL_Serie_ALL_Global_IB_RWT_GIA_Adjust.png

As to the melting polar caps having an effect.

Not so much.

Take the Arctic, where the increased seasonal melting is widely reported, all that ice is already floating, so essentially has no impact on sea level when it melts each year.

The Antarctic is harder to measure, and we have just started doing so via things like the GRACE satellites and it appears to be melting a bit around some of the coastal areas but also slowly accumulating mass in the center, so unless longer term mass balance studes show otherwise it doesn't appear to be a great contributor either (Ice sheets which are floating, like in the Arctic, again have little impact if they break off or melt)

One area that is more likely to have a more immediate impact due to faster melting is the ice on Greenland. Any net mass loss there adds to the sea level and much of it is much further from the pole than most of Antarctica is, and so has greater seasonal variation and thus would be affected much sooner by warming than most of Antarctica would.

http://upload.wikimedia.org/wikipedia/commons/5/5d/Greenland_(orthographic_projection).svg

http://upload.wikimedia.org/wikipedia/commons/2/2c/Location_Antarctica.svg

Arthur

 

[Robittybob1]

Not sure what the average is, but just using the Mark 1 eyeball, I wouldn't be surprised if the average depth was about 500 m.


At 30 cm/1000 years for the shelf and slope area, that equals 4.5 cm/1000 years for the entire ocean, which allowing for a little gain outside the shelf area itself, is about 5 mm average accumulation per century (or about 1/4 inch).

Arthur

I'm not that good at maths but at that rate the average depth would be 10,000 meters in 200 million years. Now even at 5mm /100 years it is really significant amount of material going into the oceans.
(could someone check the maths please?)

 

[adoucette]

Well then it would appear that I've probably way over estimated even the 15% layer, so it's probably a lot less than even 5 mm in 100 years.

Which was really the only point I was trying to make, is the contribution on our time frames is negligible.

And of course there are other factors that would limit the rise when you start thinking about it:

Probably the biggest one is the sediment, as it builds up and compacts into much less space.
http://en.wikipedia.org/wiki/Sedimentary_rock

Then there are subduction zones where the crust and the overlying sediment are removed.
http://en.wikipedia.org/wiki/Subduction

 

[Robittybob1]

Yes, but that's not all that's happening over those time frames.
The sediment, as it builds up and compacts into much less space.
http://en.wikipedia.org/wiki/Sedimentary_rock
Then there are subduction zones where the crust and the overlying sediment are removed.
http://en.wikipedia.org/wiki/Subduction

In my view (sometimes a bit distorted but not completely) is that people overuse subduction as the answer. What I have noted is that at these subduction zones the sediment is scrapped off the ocean plates and this tends to build islands which also take up ocean space.
Like a paint scrapper going into softened paint. There is no way all the sloppy sediment has the strength to squeeze under the continental plate!

 

[adoucette]

In my view (sometimes a bit distorted but not completely) is that people overuse subduction as the answer. What I have noted is that at these subduction zones the sediment is scrapped off the ocean plates and this tends to build islands which also take up ocean space.
Like a paint scrapper going into softened paint. There is no way all the sloppy sediment has the strength to squeeze under the continental plate!

Sure it does if it has been turned into sedimentary rock, and that would be the case when you are dealing with long intervals of time.

Secondly, when you are dealing with vast time frames then the above calculation means nothing because of the changes in the overall ocean basins.

Earth and it's oceans and continents from 150 million years ago was FAR different than it is today, so one can't extrapolate backwards that far with any degree of accuracy.

Arthur

 

[Robittybob1]

All I can say, for the science does get over my depth at times (rusty as) is that the 4 things aren't in our favour.
1. Expansion of the earth has ceased (decompression). Resulting in no increases in the volume of the oceans.
2. Greenhouse gas warming causing land based ice to melt filling the oceans.
3. Continual soil erosion filling the oceans
4. Cooling of the body of the Earth causing the volume of the oceans to decrease.

 

[Trippy]

In my view (sometimes a bit distorted but not completely) is that people overuse subduction as the answer. What I have noted is that at these subduction zones the sediment is scrapped off the ocean plates and this tends to build islands which also take up ocean space.
Like a paint scrapper going into softened paint. There is no way all the sloppy sediment has the strength to squeeze under the continental plate!

There is an element of this that occurs as part of the subduction process.

However the evidence we have available from methods such as seismic profiling allow us to see that substantial quantities of sediment are carried into the subduction zone. This in turn is supported by physical evidence in areas where we find old subduction zones and similar features.

 

[Robittybob1]

There is an element of this that occurs as part of the subduction process.

However the evidence we have available from methods such as seismic profiling allow us to see that substantial quantities of sediment are carried into the subduction zone. This in turn is supported by physical evidence in areas where we find old subduction zones and similar features.

I don't disagree with that Trippy. It is the ratio that is interesting. If this subduction had been going on for billions of years at the "full on" rate for the sedimentation (above) the layers of the Earth would have a rather different composition (proposition yet to be verified).
For the ocean plates move at quite substantial rates and so I would expect the mixing of the ex-continental material subducted into the mantle to be rather evident (I'm looking for evidence to support this statement).

 

[adoucette]

All I can say, for the science does get over my depth at times (rusty as) is that the 4 things aren't in our favour.
1. Expansion of the earth has ceased (decompression). Resulting in no increases in the volume of the oceans.
2. Greenhouse gas warming causing land based ice to melt filling the oceans.
3. Continual soil erosion filling the oceans
4. Cooling of the body of the Earth causing the volume of the oceans to decrease.

The primary reason the oceans are rising is due to thermal expansion.
Melting of land based ice is secondary.

The other two, erosion and cooling of the CORE of the earth are irrelevant on human time scales.

Arthur

 

[Robittybob1]

The primary reason the oceans are rising is due to thermal expansion.
Melting of land based ice is secondary.

The other two, erosion and cooling of the CORE of the earth are irrelevant on human time scales.

Arthur

So that makes it 5 then:
1. Expansion of the earth has ceased (decompression). Resulting in no increases in the volume of the oceans.
2. Greenhouse gas warming causing land based ice to melt filling the oceans.
3. Continual soil erosion filling the oceans
4. Cooling of the body of the Earth causing the volume of the oceans to decrease.
5. The primary reason the oceans are rising is due to thermal expansion.

So who said it was a lie? I see in 4/5 reasons the oceans meant the container that the water in the oceans sat, and the 5th example it described a property of the water itself.
So there could be a 6th reason (only happens infrequently ) but a water bearing comet arrives on Earth

 

[adoucette]

So that makes it 5 then:
1. Expansion of the earth has ceased (decompression). Resulting in no increases in the volume of the oceans.
2. Greenhouse gas warming causing land based ice to melt filling the oceans.
3. Continual soil erosion filling the oceans
4. Cooling of the body of the Earth causing the volume of the oceans to decrease.
5. The primary reason the oceans are rising is due to thermal expansion.

So who said it was a lie?

See the OP

 

[Ophiolite]

The crust floats on top of the mantle.

Both of these types of crust are less dense than the rock found in the underlying upper mantle layer.

http://www.physicalgeography.net/fundamentals/10h.html

I deduce that English is not your native language. Solids do not float on other solids and as the mantle is solid the crust cannot float on it. End of.