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pyankoff | 8 years ago

What's wrong with underwater ice melting? Ice density is lower than waters, so water level should actually decrease from that.

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Xylakant|8 years ago

it's not "underwater ice", it's "ice sitting on soil that is below sea level". The ice sheet is thick enough to be significantly above water level, but it's especially vulnerable to temperature increases in the ocean, since ocean water can start flowing under the ice and melt it from below.

pyankoff|8 years ago

Thank you, now that makes sense.

ykler|8 years ago

The article is about ice on land melting. But actually when floating ice melts it increases sea levels a little bit as well, as explained here: https://www.quora.com/If-water-is-denser-than-ice-why-do-sea... Note, especially the first answer, which says that the effect from melting floating ice is quite small and that the primary drivers of rising sea levels from global warming are melting ice on land and thermal expansion of sea water.

danieltillett|8 years ago

I hope you understand that an iceberg floating in water displaces the same volume as ice as water [1].

1. I am ignoring the complexity of freshwater and saltwater mixing.

natch|8 years ago

The relevant part of the article was talking about ice that is sitting on land. Land that is below sea level. This particular ice is not floating.

sp332|8 years ago

But ice pushed down under the water will increase the water level. If you melt it, the water level will be lower.

misja111|8 years ago

It's not the only flaw in the article. Also it chooses to ignore the fact that unlike the Arctic, the Antartic does actually not have any net ice loss at all; in some parts the ice is melting, but this loss is offset by other parts which are gaining in volume.

https://www.nasa.gov/feature/goddard/nasa-study-mass-gains-o...

doikor|8 years ago

There is a difference between ice and sea ice.

Basically Antartica has been losing land ice while sea ice has been growing.

https://www.skepticalscience.com/antarctica-gaining-ice-inte...

The important bit about sea vs land ice.

> when land ice melts and flows into the oceans global sea levels rise on average; when sea ice melts sea levels do not change measurably but other parts of the climate system are affected, like increased absorbtion of solar energy by the darker oceans.

flukus|8 years ago

Amomgst other things, that ice is acting like a plug for a lot of ice on land.