Larson B Ice Shelf In Antarctica To Disintegrate Within 5 Years

BarbaraHudson writes: A new study (abstract) from NASA scientists predicts an Antarctic ice shelf half the size of Rhode Island will disintegrate around 2020. The shelf has existed for roughly 10,000 years. "Ice shelves are the gatekeepers for glaciers flowing from Antarctica toward the ocean. Without them, glacial ice enters the ocean faster and accelerates the pace of global sea level rise." At its thickest point, the ice shelf remnant is a half kilometer tall, and spans approximately 1,600 square kilometers. "The glaciers' thicknesses and flow speeds changed only slightly in the first couple of years following the 2002 collapse, leading researchers to assume they remained stable. The new study revealed, however, that Leppard and Flask glaciers have thinned by 65-72 feet (20-22 meters) and accelerated considerably in the intervening years. The fastest-moving part of Flask Glacier had accelerated 36 percent by 2012 to a flow speed of 2,300 feet (700 meters) a year."

Comments

Re:Half the size of Rhode Island?

[tsqr]

Rhode Island is supposed to be an island. The rising sea levels are only helping it to achieve its natural state!

Probably not enough rise to make that happen.

Although it is believed that the melting of floating ice shelves will not raise sea levels, technically, there is a small effect because sea water is ~2.6% more dense than fresh water combined with the fact that ice shelves are overwhelmingly "fresh" (having virtually no salinity); this causes the volume of the sea water needed to displace a floating ice shelf to be slightly less than the volume of the fresh water contained in the floating ice. Therefore, when a mass of floating ice melts, sea levels will increase; however, this effect is small enough that if all extant sea ice and floating ice shelves were to melt, the corresponding sea level rise is estimated to be ~4 cm.

However, if and when these ice shelves melt sufficiently, they no longer impede glacier flow off the continent, so that glacier flow would accelerate. This new source of ice volume would flow down from above sea level, thus resulting in its total mass contributing to sea rise.

Re:5 years

[MrL0G1C]

Scientists predict the arctic ocean will be ice free by2012. Or maybe by 2015. Or by the year 2000. Hard to say, really.

File:Arctic-death-spiral.png

Not hard to say at all, it's clear where that spiral is heading. Zero Ice at the north pole.

Re:Fight!

[Eunuchswear]

OP:

I recall NASA predicting complete loss of arctic sea ice by 2013, and the navy predicting the same in 2016.

You:

after reviewing his own new data, NASA climate scientist Jay Zwally said: "At this rate, the Arctic Ocean could be nearly ice-free at the end of summer by 2012, much faster than previous predictions."

US Department of Energy-backed research project led by a US Navy scientist predicts that the Arctic could lose its summer sea ice cover as early as 2016 - 84 years ahead of conventional model projections.

Are you unable to see the difference?

One NASA climate scientist said "the Arctic Ocean could be nearly ice-free at the end of summer by 2012", not "NASA predicted complete loss of arctic sea ice by 2013".

As it happened we hit the lowest sea ice extent since 1979 in September 2012.

A US Navy scientist predicted that "the Arctic could lose its summer sea ice cover as early as 2016", not "the Navy predicted complete loss of arctic sea ice by 2016".

As it happens we're currently only just inside 2 std deviations of the average, looking much like 2014 and 2013.

Anyway, to see what's happening go here http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/.