Comments

You must log in or register to comment.

CrustalTrudger t1_jbocbh4 wrote

No.

First and foremost, this ignores that in calculating hypothetical sea level rise from complete melting of the Antarctic ice sheet, ice below sea level is already removed from consideration. This is explained relatively well on this page that goes through the calculation of sea level rise equivalence. So, the value of ~60 meters of sea level rise that would result from melting of the Antarctic reflects the volume of ice (converted to water and spread over the ocean surface) above sea level.

Secondly, if anything this value represents an underestimate because it does not account for isostatic rebound. In short, as the ice melts, the land underneath the ice will rise up in response to the reduction of mass above it. As such, we would expect that as ice melted, the ground surface would elevate in response and thus a good portion of the ice that is currently below sea level (because the ground has subsided) and which is not factored into the calculuation, would actually contribute to sea level rise because it would no longer be below sea level when it melted. For a more thorough discussion of what Antarctica without ice might look like, you can check out this previous thread.

Finally, the sea level rise equivalents are pretty much only dealing with mass and not considering the steric components of sea level rise (i.e., the changes in sea level rise due to changes in density related to either temperature or salinity). Melting all of Antarctica would have a complicated effect in this regard. It would directly reduce density (and thus reflect expansion, so more sea level rise) through freshening, but adding all of that cold water could temporarily reduce temperature (at least regionally) increasing density (and thus reflect contraction, so less sea level rise). Presumably though, to be able to melt all of Antarctica would reflect relatively high average air and ocean temperatures, so this cooling would likely be temporary so you would have to also account for potential thermal expansion after all that melt water had a chance to heat up to whatever the average ocean temperature was at this hypothetical time.

45

foodtower t1_jboh00u wrote

The vast majority of Antarctica's ice is above sea level, and its average thickness is over is above 2 km: https://en.m.wikipedia.org/wiki/Antarctic_ice_sheet

That's a lot of water that is currently above the ocean, that would be added to the ocean.

14

[deleted] t1_jboraft wrote

[removed]

0

JAWMerlin t1_jbotgqs wrote

You do realise that those 2 km of ice have weight and that they aren't just a wall around Antarctica but cover the entire continent, right?

5