Possible Flaw in Global Warming Theory?

[Fatstep]

I'm not good at convincing, but something just struck me.

 

If water expands as it freezes, that means it contracts when it thaws.

 

I was wondering if there were any estimates at how much ice is below the surface on the earth(icebergs, Antarctica). What if all of the ice on Earth's surface melted, would the contraction of the water not make up for the extra volume gained by water going into the ocean?

 

It seems like it would to me, and again, I am sorry I don't really know how to write these.

[Zythryn]

Freshwater is densest at 3.98C (Water - Wikipedia, the free encyclopedia). At temperatures higher than that, it expands.

My guess is that the contraction as the water first thaws is far less than the added water from ice above the surface and the formerly cold water as it warms.

I am not sure what the densest point for saltwater is, however I am guessing that it works in a similar manner (contracts to a point, then expands again).

Good question though:)

[ughaibu]

Try experimenting with an ice cube in a glass of water.

[CraigD]

What if all of the ice on Earth's surface melted, would the contraction of the water not make up for the extra volume gained by water going into the ocean?

Changes in sea level due to ice melting depends critically on whether the ice is floating (as is the case for most of the north polar ice) or resting on land (as is most of the south polar ice and continental and island glaciers).

 

Per archimedes principle, anything floating in water, be it ice, a boat, a swimmer, etc., displaces a volume of water of equal mass. Since the mass of the water in ice floating in the ocean doesn’t change when it melts, the amount of ocean water it displaces doesn’t change when it melts, and sea level is unaffected.

 

If frozen water resting on land melts and runs into the sea, the effect is the same as if an equal mass of liquid water was added to the sea. Sea level is increased.

 

So, while the melting of the north polar ice cap raises environment and climate concerns, it doesn’t threaten to increase average worldwide sea levels. The major concern with north polar ice melting is that it will change the salinity of northern oceans, effecting global ocean currents, and changing the climate of temperate northern regions, such as the British Islands.

 

Unlike north polar ice, most south polar ice rests above sea level on the continent of Antarctica. When this ice melts and runs into the ocean, average worldwide sea levels are increased. This is also true of ice held in glaciers throughout the northern hemisphere, particularly Greenland.

 

If the entire Greenland ice sheet, the world’s second largest, were to melt, global seal levels would rise about 7.6 m. If the entire Antarctic ice sheet were to melt, the increase would be about 60 m. Note that, since much of the solid surface of Antarctica (and also Greenland, though only slightly) is below the current sea level, these predictions are slightly over stated.

 

Although no accepted scientific theory predicts that such tremendous melting will occur within the next 4 billion years, there’s clear evidence that some glaciers are, in the short term, melting. For example, the Greenland sheet is measured to be melting at about 2.39e11 m^3 /year (0.014%/year), which calculates to a sea level increase of 1 mm/year. The Antarctic sheet is more difficult to measure. Data suggest it has gained mass in the past few decades, but since 2002, has been loosing about 1.52e11 m^3/year (0.0005%/year). Predicting future trends in the mass of the world’s glaciers is difficult.