Antarctica’s floating ice shelves, the doorstop of the continent, are melting away
Antarctica’s floating ice shelves, the doorstop of the continent, are melting awayMorning Mix
By Sarah Kaplan March 27 at 5:41 AM
NASA’s DC-8 flies over the Brunt Ice Shelf in Antarctica in 2010. (Michael Studinger/NASA via Reuters)
How bad is Antarctic ice loss? Let scientists count the ways. In December, researchers reported that West Antarctica, one of the world’s most unstable ice sheets, is collapsing faster than anyone had predicted and contributing to rapid sea level rise. Earlier this month, the same was found to be true of Totten Glacier in East Antarctica.
This week, glaciologists report the massive floating ice shelves that form a fringe along the continent’s coastline are also deteriorating. For hundreds of thousands of years, these shelves have served as doorstops for the entire Antarctic ice sheet system, holding back millions of cubic miles of glaciers from surging toward the sea. And now they’re losing heft faster than they can be replenished.
NASA has a DC-8? I haven't seen one of those flying since 1994. Evergreen used to operate one (or a few) out of Portland, Oregon. Oh, darn; Evergreen is gone now.
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The reason is simple, the West Antarctic Ice Sheet (Ice sheets do NOT float, instead lay on a cushion of ooze that permits them to "flow" but otherwise "Grounded" on land). The West Antarctic Ice Sheet (WAIS) is unstable, for while it is "grounded", it is also below sea level (The Sheets are so heavy that water is kept out of the Sheets while they move to the Ice Shelves).
Now Ice Shelves FLOAT on top of the ocean. The Arctic Ice flow is one huge Ice Shelf. Ice Shelves, if they melt, will take up the same room in the ocean as water as those Ice Shelves displace today.
The problem is the Ice Shelves are shrinking and thus permitting more and more warmer water to interact with the West Antarctic Ice Sheet (WAIS). As the Ice Shelves melt, more warm water reaches the West Antarctic Ice Sheet (WAIS) which makes it less stable.
The problem with Ice Sheets (as opposed to Ice Shelves) is that Ice Sheets, being grounded on land, do NOT displace any water they would become if they would melt or become an Ice Shelf. Thus if the West Antarctic Ice Sheet (WAIS) would break up and start to Float i.e. become an Ice Shelf, world wide sea levels will raise 16-20 feet.
The big fear is when the Antarctic Ice Sheet (WAIS) does break up and start to float. That is something that will raise world wide sea levels 16-20 feet in days not decades.
It is believed this happened 120,000 years ago, causing massive increase in sea levels, followed by a massive decline in sea levels within a Century (and maybe sooner, i.e. decades). The destruction of the West Antarctic Ice Sheet (WAIS) is believed to have push into the Ocean a huge amount of minerals needed by Algae. No Materials (which include Iron) no Algae, additional source of these Minerals, a huge increase in Algae, with a huge increase in fixing of Carbon from the Atmostphere and a drop in world wide tempertures:
http://www.imaja.com/as/environment/can/journal/madhousecentury.html
Yes, it is called the "Madhouse Century" for it must have been pure hell if you lived in the coast. A sudden loss of coastal plains. especially in Louisiana to Maine, followed by a massive increase in such coastal plains:
Here is a map of Florida showing its coastline 120,000 years ago (pre-last Ice Age, Make "A" on the Map), Present day (Marked "B" on the map) , and 20,000 years ago (Height of last Ice Age, marked "C" on the map). Look at how much of Florida did NOT exist AFTER what is now considered the last time the West Antarctic Ice Sheet Collapsed compared to present day, and how much Florida was AFTER the end of the Mad House Century.
In the article the two extremes are 100,000 years apart, but in reality the two extremes may have been less then 100 years apart.
http://www.flmnh.ufl.edu/vertpaleo/aucilla/arpp05.htm
More on North America's coast line changes over the last 120,000 years:
http://www.dandebat.dk/eng-klima5.htm
Global Warming MAY cause the next Ice Age to start. Right now the Scientists involve concentrate on the bad parts of Global Warming independent of the West Antarctic Ice Sheet suddenly collapsing for the increase in Temperatures today is much more extreme then we can determined what was the increase just before the Mad House Century. Such increase in Carbon in the atmosphere and increase in world wide Temperatures was last seen in the Permian age and that age ended in the single greatest extinction known today.
Thus are we facing a return to the Permian Age or just another Glacial age is unknown but most scientists are leaning to the Permian Age but I wanted to mention the other alternatives, which in many ways worse.
