Greenland
"(Vikings colonized a forest covered Greenland for several hundred years. grew crops and raised sheep)"
I wish people would get over this silly notion that Greenland was ice free in Viking times. If that were true how can they drill ice cores there that go back 100,000 years? At best the last time Greenland was largely ice free was during the previous interglacial around 100,000 years ago when sea level was 20-30 feet higher than now. It's possible that there was marginally less ice during the Viking times than there is now but it's absurd to think that Greenland was even 25% ice free back then. The fact that sea level was not significantly higher then is proof of that.
Also, do you have a cite for your statement that the Antarctic glaciers have been in a melt phase for the past 600 years? I've never heard that before.
