Friday, March 03, 2006

Antarctic ice sheet is shrinking, but only by a fraction

This headline will always make the news these days! But the ensuing article in today's Daily Telegraph shows remarkable restraint.

The concept of using satellite gravity measurements to determine how much ice is melting on the East Antarctic Ice Sheet is an interesting one. In theory it should be accurate but as the scientists themselves acknowledge that "corrections had to be applied to the signal for this method to work and that the accuracy of the final assessment of ice-sheet mass balance depended on how accurate these corrections were".

The results are not as profound as the headline might have us believe. First of all, the ice sheet is not melting that much. But, and here's the rub, the ice sheet was predicted to expand if global warming is taking place - apparently global warming should induce greater precipitation and accumulation of ice - so now we don't know what to think!

I rather suspect that the results are too close to call one way or the other. But funding must continue. Hence the headline.

3 Comments:

Blogger maksimovich said...

The GRACE project opens some interesting observations,that may explain some of the phenomena that is always misread by the MSM.

Whilst Rapely of the Brtitsh Antarctic says it is an wakening giant the melt loss is indeed miniscule.220000-250K for total loss.Or 1000 years to raise sea levels by 15 inches.Indeed this figure may be too high as a substantial portion of the WAIS is already below sealevel.

The great weight of the icesheets have compressed the mantle by .5 km.This inverse topology means substantial parts of the icesheet -ocean interface is already below sealevel.

Now the interesting part of the GRACE project is the quantification of the gravity waves ie the twice daily lunar tides.This movement at the poles involves a tremendous amount of water flow at the poles.

" The ice is a mile thick in parts, and the tides are so large that they can lift the shelves – with a combined area bigger than the state of California – as high as 15 feet.

Scientists believe that these unseen tides can carve into the ice from underneath and eventually cause pieces to break off, as part of the Larsen Ice Shelf broke off in 1995.

These are the researchers words a simplistic cause.

http://researchnews.osu.edu/archive/icetide.htm

6:27 AM  
Blogger Paul Ashton said...

Now this is interesting! How come the Daily Telegraph article only focused on melting of the ice and not erosion of the ice? The practical significance of eroding ice and iceberg formation to shipping is surely significant if not sensational. Thanks for the contribution!

8:09 AM  
Blogger Paul Ashton said...

The other important difference between reporting ice melt and ice erosion could just be the fact that the media associates melting with anthropogenic global warming (whether it is proven or not) while ice erosion due to tidal activity is something that has no obvious human intervention.

And that is what this blog is all about - pointing out that the media generally only prints what it thinks will sell newsprint.

9:52 AM  

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