Re: Greenland was actually, you know green.....
'The 'Vikings' spent @500 years in Greenland as a fair chunk of it it was a green a lush verdant forested paradise,'
There were no forests in Greenland. It was low scrub and grassland. The wood was imported from Norway and from Iceland (hastening that country's ecological collapse). It was always a marginal agricultural society even during the warmest period reliant on a hay harvest to keep animals alive in the winter. As soon as the conditions began to deteriorate there was no slack in the system and the inflexibility of the Norse economy doomed them to starvation.
There's a very readable account of the Norse settlement of Greenland and its rather grisly fate in 'Collapse' by Jared Diamond.
'On this basis, could someone please provide evidence of the ocean levels falling during the period of refreezing and the subsequent post industrialisation melting everything (allegedly).'
By all means:
Nunn, P. D. (2000), Environmental catastrophe in the Pacific Islands around A.D. 1300. Geoarchaeology, 15: 715–740. doi: 10.1002/1520-6548(200010)15:7<715::AID-GEA4>3.0.CO;2-L