The Climate is always changing and man has zero control over it. From 800 AD to about 1300 AD the Earth went through a global warming period that was 1.5 degrees warmer than now as the ice core record shows below. During this warm period in about 1000 AD the Vikings discovered Greenland, named because of its warm tropical green vine covered climate. Europe had open trade with Greenland Vikings for centuries until the little ice age kicked in because of the Maunder Minimum Sun Spot cycle. And cut off trade with Greenland for Centuries. Contributing to the starvation of the Viking colonies there in Greenland. Which is now covered in ICE.

This graph was published by he IPCC in 1996.

During this 500 year long warm period England and Northern Europe was so warm that Grapes were grown as far north as Scotland. Wine was the top export from these regions. Agriculture flourished, people prospered and this became the period in time when the great Cathedrals were built.