Alt. Hist. request, Vikings make a go of the "New World"?

[Anomalocaris]

Norway and Sweden weren't exactly tropical paradises to begin with.  The Norse knew about cold.

Norway and Sweden hasn’t seen Greenland caliber of cold since before the end of the ice age.

Nowhere is Viking animal husbandry as challenged as in Greenland. There the low productivity of pastoral land and the extreme length and severity of winter means cows stay indoors on grass collected during previous summer during winter. So finely balanced on knives edge is this that the cows basically subsist on starvation diet through the winter and become so weakened and emaciated that the Viking farmers had to carry each of them by hand to their pastoral land when spring finally arrives.

Any late arrival of spring is diseasterous as the cows will die and the farmer is doomed.