2007
The most compelling data for the net change of ice sheets is provided by the gravity satellite mission GRACE, which shows that both Greenland (Chen et al 2006) and Antarctica (Velicogna andWahr 2006) are losing mass at substantial rates.
http://iopscience.iop.org/1748-9326/2/2/024002/pdf/1748-9326_2_2_024002.pdf
2010
Those are scary numbers, but a new study published in the September issue of Nature Geoscience suggests that the true melt rate might be much slower than that. (Access a PDF of the study here.) A joint team of American and Dutch scientists took another look at the GRACE data and found that Greenland and West Antarctica may be melting just half as fast the earlier studies estimated. As researcher Bert Vermeersen, a professor at Delft University of Technology in the Netherlands, told the AFP, the earlier estimates failed to account for glacial isostatic adjustment—the rebounding of the Earth’s crust after the end of the last Ice Age:
http://ecocentric.blogs.time.com/2010/09/09/climate-change-a-slowdown-on-polar-melt/
Success in science depends on objective skepticism. Caution, if not reticence, has its merits.
– James Hansen
Success in science depends on SILENCING objective skepticism. Caution, if not reticence, WHEN ALLOWING ACCESS TO YOUR DATA, has its merits.
Fixed it for you, Steve. (:-
That is more accurate
Perhaps I am being thick – but…….
We keep being told that GRACE shows more ice being lost now from Greenland + West Antarctica than previously estimated.
As GRACE is the first time we have had anywhere near scientific measurements then surely previous estimates have ver little validity at all and in reality we have no idea whether the rate of ice loss is up at all.
If on the other hand previous estimates were accurate then why do we need GRACE?
The Grace satellite is a new program, as with all new programs there are bond to be surprises and unexpected details surfacing.
In this case the project folks did not realize that there is a rebound effect from the weight of the ice being removed from the underling mantle . Basically if you remove weight in the mega tonne range the earth underneath the ice rises. This would normally be just another one of those things ” we forgot about” and we are making adjustmentsto compensate. Unfortunatly certain members of the scientific community jumped on the preliminary results as “PROOF” . The media followed in lockstep for the most part.
Unfortunatly for those involved when the “old” methods of checking elevations was used as a cross check fecal matter hit the rotary air impeller.
In a world of real science and new ways of measuring this simply would be a whoops moment and a number of people with pasty white skin and buldging foreheads would go back to their computer and write some code, do more measurements , wash , rinse , and repeat until the satelite data matched what the guys with the tapemeasures were getting. In this case the political, economic forces of change pushed preliminary results out with a brass band in attendance as validation of their thesis.
Fun times were had by all, until it came time to clean up the mess from the rotary air impeller…..
(pun alert) Seems like more half-fast climate science to me.
Steve are you suggesting that the revised GRACE figures show something different than both Greenland and Antarctica ‘losing mass at substantial rates’?
Given that sea level has hardly changed since 2005, that seems like a safe bet
So this is half the ice loss annually from Greenland and Antarctica that wasn’t included in the IPCC predictions at all because of uncertainty about knowing how much ice loss there would actually be.
You must be excited about how the IPCC was right on about this one!