If All Antarctica's Ice Melts...

 I get in my email feed every day something called Science X Newsletter.  It comes overnight, so today I get to read yesterday's offering. It includes a lot of areas of discoveries, but this one hit my particular interests. If all the ice covering Antarctica were to melt, how would it affect global sea level rise, and why?

In case you haven't been paying attention to this piece of the world, perhaps except for the cute penguins, things have been changing. Huge chunks of ice shelves are being undercut by warm ocean water and are breaking up. Ocean currents are already changing, some of which like our Gulf Stream, are either not streaming or are curving backwards in places, and sometimes both. These things I already knew, having been following this news for quite a while. We've been hearing all kinds of estimates from all kinds of sources, both scientific and not, on how much total loss of ice down there would affect sea level, just like people have been doing what amounts to guessing about the Greenland ice sheet, or even total planetary ice loss.

Scientists have more information now than they had previously, and new ways of gathering it, including satellite imaging. I won't get into that. If their "hows" interest you, go read up. What impressed me the most are two conclusions about what will happen when all the southern ice is gone, along with a new number of how high seas will rise just from Antarctica.

First, the number: 58 meters of ocean rise. For those of us with the feet and yard system of distance, i.e. Americans, that is over 190 feet! Just from Antarctica! (You rethinking that oceanfront property yet? How about your own private island dream home?)

Why so high? First, glaciers are a weird kind of ice. The snow piles up and piles up and compacts into ice, which then under increasing volume itself compacts down denser than, say, what pops out of your icemaker to put in your drinks. By the time those molecules have become water they have expanded back to the same volume as the rest of water on the planet. 

Second, all that weight leaving one spot on the globe allows it to rise. What had been deformed now can reform. Without all that weight, it has less gravity. Right now Antarctica attracts a higher amount of water to itself, pulling it away from, say, Florida. If that seems unlikely, just remember how much the pull of the moon way out in space can affect our planet's water in what we know as tides. Ocean levels will rise less near both poles since both still carry glaciers to melt away, thus higher gravity, and will rise around the rest of the globe. So that 190 feet or 58 meters will be just from Antarctica. It won't be the height at which it stops.

We just haven't quite figured out the "when" yet. But the graphs being generated these days on things like CO2 and methane in the atmosphere are rising straighter and straighter rather than looking like the zigzag top of a mountain range. Temperature graphs globally are doing the same thing.

We are living in "interesting times". The Chinese consider that phrase a curse.