Couldn't track down a full copy of the paper, but abstract here.  And brief discussion here.

Climate Change Linked to Social Collapses in Greenland Since 800 B.C.

A record written in algal fat reaffirms the role of climate change in determining the fate of Greenland's Vikings and other inhabitants

By David Biello  | May 30, 2011 | Scientific America

http://www.scientificamerican.com/article.cfm?id=climate-change-and-collapse-in-greenland&WT.mc_id=SA_DD_20110531&posted=1#comments

By David Biello  | May 30, 2011 | Scientific America:

“The Norse came. . . The land was indeed green when they landed—and stayed that way for several centuries until natural variations in the planet's climate cooled the world's largest island by 4 degrees Celsius.”
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You know reading David Biello opening paragraph was like getting seriously sideswiped right out of the driveway.  What can I say, seems to me that any portrayal of MWP Greenland, demands the inclusion of the part about the “Green” actually being a narrow, lowlands skirt between a massive highland continental glacier and the Atlantic Ocean.    rest of article was ok,   guess I'm just disappointed in the modern SA.

Mind you that bitch is totally independent of the study in question - pure media critique, not to be mixed up with the science.

I don't know about you guys, but I found it rather interesting the ice models are indicating the Greenland Ice Sheet may already be committed to collapse. 

If they're factoring in the Arctic albedo flip then I would believe it.  And you know if the GIS goes, say sayonnara to the WAIS as well.

And Miami

And ________, etc, etc, etc.