NASA has recently released updated measurements of ice loss in Antarctica, revising their predictions upwards by almost 40%. Previously, the East Antarctic ice sheet was thought to be stable but now an estimated 57 gigatons (57,000,000,000 tons) of ice per year has been lost over the last 3 years. West Antarctic ice loss is also confirmed at 132 gigatons of ice per year. The ice loss has the potential to raise sea levels by anything from a few metres to over 70 metres (230ft) if the high melt rate continues over the coming decades.
These findings were determined by studying gravity data from a NASA/German Aerospace Center's satellite called GRACE (Gravity Recovery and Climate Experiment). East Antarctica contains 90% of the world’s fresh water. The images show the ice loss from the latest research and also the temperature rise measured over Antarctica by NOAA (National Oceanic and Atmospheric Administration). There is a high correlation between increased temperatures and ice melting in the region.
Read more about polar melting:
Arctic Ice Melting Facts: http://greenmuze.com/blogs/eco-geek/1697-arctic-ice-melting-facts.html
Wilkins Ice Shelf Fracturing: http://greenmuze.com/blogs/eco-geek/993-wilkins-ice-shelf-fracturing.html
Their work seems to show a time lag of anywhere from 10 to 30 years or more before increased water levels in one ocean circulate to another. This means that locally there is a much higher sea level due to local melting and land locked ice entering the ocean. Other researchers point out that increased sea levels can lead to increased ice shelf break-up and faster flowing glaciers which would seem to indicate an increasing rate of ice entering the ocean, in a positive feedback cycle. Uncovering more open ocean will increases solar absorption.
It would seem very likely that the ocean, wave, ice shelf interaction and break-up of ice-shelfs, would be very much different as the local sea level rose. So while the percentage ice loss is small, the significant point is that it has been seen to be increasing, while previously it was thought to be completely stable. It therefore seems that the loss rate will only accelerate, especially given these local effects predicted by Dr.Stammer in his studies in other ocean regions, so the rise in sea level will likely be more significant.
It is obviously a complex system and it seems the estimates vary widely - but it would seem that the 0.7mm level rise would only get bigger over time.
If you take Dr.Stammer's local sea level rise into account, let's say 20, then your estimate of 7cms global average will be 140cms locally.
Now, if there is also an acceleration in the melt rate for the reasons stated, let's say 5% per year, then that 0.7mm becomes nearer 3mm after 30 years, and is 90mm per year after 100years. That gives an accumulated 1.8m sea level rise over 100 years as an average, not accounting for the spreading out effect. Now if you add in the local effect, then clearly the local sea level rise will be in the order of 10-20 metres and that 5% rate of increase would be much higher - so I am inclined to believe that the sea level rise will be much bigger than 7cms over 100 years, and likely to be at least a 1-2metres or more, as an average.
written by tjw , January 13, 2010
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"The ice loss has the potential to raise sea levels by anything from a few metres to over 70 metres (230ft) if the high melt rate continues over the coming decades."
Also you should tell your readers that the total amount of ice in Antarctica is 30,000,000 cubic kms or to put it into your terms
30,000,000,000,000,000,000 tons so in actual fact the current ice loss for Antarctica is actually 0.00065% of its total mass.
written by snowmaneasy , January 12, 2010