Hans schrieb:
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> Dennoch gehst du damit ihm (Ghost) auf den Leim.
>
> Die beste Argumentation ist die, dass Grönland
> während der letzten 10.000 Jahre mehrfach
> bedeutend wärmer als heute war, der Eisschild aber
> dennoch nicht abgeschmolzen ist.


Bedeutend ist relativ, insbesondere in Bezug auf das was Groenland bevorsteht. Natuerlich war es vor 10.000 Jahren nicht nur in Groenland waermer als heute. Das war es sogar global! Seitdem wird es bekanntlich schleichend kuehler bis Anfang des 19.Jh ... siehe auch hier: [www.zamg.ac.at]

Die Frage ist also anders herum zu stellen! Warum hat das Groenlandeis seitdem nicht wieder zugenommen? Aber zum Glueck gibts die Wissenschaft, und deren Ergebnisse kann man nachlesen. Here we go:

[Long, 2009]

"Reconstructing the magnitude and timing of the neoglacial advance is diffi cult because a growing ice sheet destroys former ice limits. Ice sheet models provide the best means of estimating ice volume changes, especially when they are constrained by sea level and other geomorphological evidence. Current models suggest that despite the 50-100 km advance of the ice sheet margin, especially in west Greenland where it was most pronounced, the neoglacial regrowth of the ice sheet caused a relatively small draw-down of global sea level, amounting to <0.2 m (Tarasov and Peltier, 2002; Fleming and Lambeck, 2004; Simpson et al., 2009). This is equivalent to a rate of sea-level fall of ~0.05 mm/a when averaged over the past 4000 years."

[Vinther et al., 2009]

"The average rate of elevation change at the Camp Century and DYE-3 drill sites is also shown in Fig. 2c. It can be inferred that elevations at these two sites near the margin of the GIS respond rapidly to Greenland temperature change. The most significant periods of decrease in elevation coincided with the climatic optimum 7-10 kyr before AD 2000. This suggests that the GIS responds significantly to a temperature increase of a few degrees Celsius, even though part of the GIS response in the early Holocene was also associated with ice break-off resulting from rising sea level. The colder climate prevailing during the past two millennia induced a slight increase in elevation of the GIS at these sites." ...
"The GIS temperature and elevation histories presented here also suggest that the GIS responds more vigorously to climatic change than indicated by the three-dimensional models used for GIS projections. It is therefore entirely possible that a future temperature increase of a few degrees Celsius in Greenland will result in GIS mass loss and contribution to sea level change larger than previously projected."

Alles keine Geheimnisse. Man muss sich nur informieren lassen wollen!

Cheers KarSteN

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 "The widespread assumption that the ability to calculate an ordinary least squares regression is
   equivalent to understanding a complex system never ceases to amaze." - [www.realclimate.org]