moi621 (imported) wrote: Thu Feb 24, 2011 11:58 pm
Was it hot enough to graze cattle in Greenland as the Vikings did only 1K years ago?
Moi
How big do you suppose the polar ice cap was then?
Those who do not know history are
( )O( )'s
Hi Dave

&
You are supposing that the stories about Greenland are factual. In point of fact the Grnlendingasaga says specifically "Hann [Eirikr inn Rauði] gaf nafn landinu ok kallaði Grnland, ok kvað menn þat myndu fýsu þangat farar, at landit ætti nafn gott." (He gave a name to the land and called [it] Greenland, and said men would want to journey there if the land possessed a good name.) That statement suggests that Greenland wasn't all that green in reality. Though some insist on the absolute veracity and integrity of Erik the Red, the reason he was in Greenland in the first place was that he had been exiled (outlawed) for antisocial behavior. We also read in the Grnlendingasaga that there was a period of severe famine during the early years of Erik's settlement, not what you would expect from a lush dairy farm with abundant pasturage. While the sagas tell that Erik had 40 head of cattle, excavations have found his farmstead but no trace of the cattle; it would be very odd if no cow had ever been slaughtered in Greenland unless there were no kine there in the first place.
Moreover, the local conditions in Greenland (or western Europe) are not indicative of the global climate. The temperature of Greenland is dependent not on the icecap but on the Gulf Stream. The end of the Ice Age marked a general global warming, but western Europe was struck by three separate returns to near polar climate, the Younger Dryas, The Older Dryas and the Oldest Dryas, each of which is thought to have been a paradoxical response to global warming. As the temperatures in the northern hemisphere rose, the ice melted, forming large glacial lakes (the biggest of which was Lake Agassiz) when these lakes finally drained through Hudson's Bay into the north Atlantic, they lowered the salinity of the ocean water and thus reduced its heat capacity. Consequently, the Gulf Stream brought less warmth to western Europe (we must always remember that Paris and London are roughly at the same latitude as Labrador; the pilgrims were astonished at how bitter the New England winters were compared to the Gulf Stream-warmed British winters). Temporary El Niño-like conditions could have easily driven a more powerful Gulf Stream further north; drought in the midwest would have reduced the flow of the Mississippi thus increasing the salinity of the Gulf waters and consequently the heat capacity of the Gulf Stream.
In short, there is no reason to suppose that any temporary (and the Greenland and Vinland experiences were clearly of very limited duration and technologically and economically unsustainable) amelioration in the local climate of Greenland depended on a warmer global climate or on reduced ice caps.
Knowing history depends on being able to read and evaluate the primary sources.