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Old 09-17-2013, 11:23 AM   #963 (permalink)
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Originally Posted by P-hack View Post
And yet another heavily skewed video, if the actual remaining ice was as small as the ice there the sea levels would already be at maximum. For F#@ks sake already.
You seem to be lacking information about sea level rise and arctic sea ice. If this isn't something you've looked into much, that's perfectly understandable, but let me see if I can explain it to you.

The ice in question, for that video, and for sea the sea ice discussion that Niel quoted, is floating on the ocean - that means that the melting of that ice will not, by itself, raise sea level - it's already IN the sea.

There are two major factors that contribute to sea level rise. The first, and the one that's been responsible for most of the sea level rise we've seen so far, is the fact that as water warms, it expands. Most of the energy that has been trapped on Earth due to the rise in greenhouse gasses has been absorbed by the ocean. The water has warmed, in a number of areas, and so it has expanded, causing a rise in sea levels.

The second major factor is the melting of LAND ice. There are three categories here. One is Greenland - the ice "cap" on top of the island of Greenland; one is a similar cap on the continent of Antarctica; the last is the numerous glaciers in high mountain ranges around the world.

When land-bound ice melts, that's water that is being added to the ocean, and so it causes sea level to rise.

The reason the melting of arctic ice can, in the long term, cause sea level rise is that white ice reflects more energy than dark water. Less sea ice means more sunlight is absorbed, and the arctic sea warms a bit, which melts more ice, and makes it warm more, and so on. That will increase sea levels a little, but the bigger issue there is the effect it will have on Greenland.

Greenland, to reiterate, is land-bound ice, so if it melts, it's added to the sea level. As arctic SEA ice melts, it warms the whole region, and means that Greenland melts faster.

So while the increased melting shown in the video will, over time, add to sea level, the ice melt itself won't directly raise sea level any more than melting ice cubes floating in a glass of water cause it to overflow.