http://www.nasa.gov/centers/goddard/news/topstory/2003/0210rotation.html
Posted on 05/18/2016 5:31:55 PM PDT by NormsRevenge
Paris (AFP) - A rapidly melting glacier atop East Antarctica is on track to lift oceans at least two metres, and could soon pass a "tipping point" of no return, researchers said Wednesday.
To date, scientists have mostly worried about the Greenland and West Antarctic ice sheets as dangerous drivers of sea level rise.
But the new study, following up on earlier work by the same team, has identified a third major threat to hundreds of millions of people living in coastal areas around the world.
"I predict that before the end of the century the great global cities of our planet near the sea will have two- or three-metre (6.5 - 10 feet) high sea defences all around them," said Martin Siegert, co-director of the Grantham Institute and Department of Earth Science and Engineering at Imperial College London, and the study's senior author.
From the air, the contours of Totten Glacier -- roughly the size of France -- are invisible because the entire Antarctic continent is covered by a seamless, kilometres-thick blanket of snow and ice.
(Excerpt) Read more at yahoo.com ...
The “stacked” ice you speak of is mostly located on the interior of the continent. The temps on the continent are nowhere close to allow ice to melt.
The ice that is melting is on the ice shelves. This ice is located along the coast. Some areas along the coast do get warm enough for some of the ice on the shelves to melt. This is ice that is already in the water.
Climate change alarmists pray on the ignorance of physics.
1 glacier is holding enough liquid water to raise global waters by 12+ feet? Forgive me if I find this claim insanely incredulous.
I mean its been a while since I’ve done this sort of math but if the surface area of of a sphere is 4 pi R^2 and the radius of the earth is about 4,000 miles and 70% of the earth is covered by water, that means the surface area of the earth covered by water is something like 138000000 square miles. So the glacier would need to hold the volume of 12 feet * the volume of 138,000,000 square miles to raise water levels that far... so, color me dubious of the claim.
Sorry that’s 6 feet x 138,000,000 square miles... I still highly doubt that much volume is in any 1 glacier on earth.
(IF this piece of ice was entirely above sea level now, perched on top of Antarctica.)
If it were a berg, floating in the ocean, 90% would be underwater now, leaving only 10% sticking out.
When that melted, only .944 foot ocean rise would be noted.
so the sea levels will go DOWN!!
This can be tested, in a glass, in your kitchen.
I'm no math expert; but simple algebra showed me it is!
(If the right conditions are met.)
Don’t forget; with more water in oceans; the tides will be...
1. Increased.
2. Decreased.
3. Stay the same.
http://www.nasa.gov/centers/goddard/news/topstory/2003/0210rotation.html
“From the air, the contours of Totten Glacier — roughly the size of France — are invisible because the entire Antarctic continent is covered by a seamless, kilometres-thick blanket of snow and ice.”
I imagine this is just sloppy writing by the reporter, but if the glacier is invisible due to covering snow and ice, it seems to me that it is not melting. OTOH, if it is melting anyway, it has to be because of subsurface warming, not global warming.
This is an experiment you can do yourself in about 30 seconds.
Use a glass so you can see to the bottom. Fill it with ice to the top. I don’t care how big the pieces are. Now, start adding water until the water reaches the top.
How much ice is resting on the bottom?
Siegert and the Grantham Institute are rabid hucksters promoting the globull warming, er “climate change” hoax. Nothing they say can be taken seriously.
Here's the answer: When the water reaches about 92% of the height of the block.
If you were filling the bathtub with seawater the block would float when the water reached 89% of the height of the block.
The reason why some glaciers in Antarctica rest on the bottom of the ocean is that the depth of the ocean in that location is less than 89% of the average height of the glacier.
By the way, if you put a 10-lb block of ice in your bathtub and fill the tub to less than the height at which the block floats, then when the block melts the water level will be higher.
That’s not valid. The glaciers have a surrounding volume of water infinitely greater than a bathtub. You would have to ensure the relative container size (bathtub, ocean) are relative to the size of the block of ice (10lb, glacier). The pressure differential is nowhere near the same. Water has weight, so the further you go down, the higher the pressure. This creates a push upward for buoyant objects to the least path of resistance.
It’s about the buoyancy support of the surrounding water. A 10lb block of ice would float in the ocean. It would not in a bath tub because of volume bouyancy support not being equivalent...the pressure differential being orders of magnitude apart.
Yes, it is. The explanation I gave is valid for any size block of ice from an ice cube to a giant glacier as long as the top and bottom of the block are flat and the sides are vertical.
Let h be the height of the block.
Let A be the area of the top or bottom.
Let d be the depth of the water from the bottom of the block to the surface.
Let r1 = density of fresh water
Let r2 = density of seawater = 1.029 x r1
Let r0 = density of ice = 0.9167 x r1
(all densities given as weight per unit volume)
Volume of ice block = h x A
Weight of ice block = h x A x r0
Pressure at bottom of ice block = d x r2
Force on the bottom of the ice block = d x r2 x A
The ice block will float when the force from water pressure on the bottom is greater than the weight of the block:
d r2 A > h A r0
This is the same as:
d r2 > h r0
or:
d/h > r0/r2
But r0/r2 = 0.9167/1.022 = about 89%
So the block will float only when:
d/h > 89%
A 10lb block of ice would float in the ocean.
If it was in a very calm part of the ocean where the water depth was less than 89% of the height of the block, it would not float. The size of the body of water is irrelevant.
My guess is a meteor hitting water, but not sure why it only affected Washington, unless it manages to hit some blocked up huge reservoir of water (but where was THAT stored..???)
I've heard that at the end of the last ice age there was a huge lake of melted water that was held back by an ice dam in Montana.
One day the ice dam broke and created the mother of all floods. The water was 500 feet deep when it came through the Portland area. Apparently this is one thing that created the Columbia Gorge.
Reading up a little on this, the current thinking of geologists is that there were multiple flood incidents like this which are called the Missoula Floods.
The volume of extra water is equal to about 2 1/2 percent of the volume of the ice block.
Weight of block = h x A x r0
Volume of fresh water from melted block = (h x A x r0)/r1
Volume of block below the water line = d x A
Volume of extra water produced when an ice block resting on the bottom melts:
h x A x r0/r1 - d x A
= ((0.9167 x h) - d) x A
Volume of extra water produced when a floating ice block melts:
= h x A x (r0/r1 - r0/r2) = h x A x (0.9167 - 0.8909) = h x A x 0.0258
So it might be possible to trick someone by having some ice floating in a glass filled with very salty water. When the ice melts the glass should overflow. (Because of surface tension you would have to make sure that there is a lot of ice.)
I just tried the following experiment. Although the ice is not even all melted yet, it is clear that it works.
Mixed up some very salty water. Left some room in the glass. Dropped in ice cubes until the water level reached the top. Waited. The water overflowed.
(For an explanation, see #132, #134, #136.)
I previously said that a melting glacier in the ocean or ice in a glass of water could raise the water level when it melted if the ice was large and heavy enough to be resting on the bottom.
But it is also true that even if the ice is floating, as long as it is floating in salt water, it will still raise the water level a little when it melts.
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