I suppose the Medieval Warming Period was caused by Vikings, Huns and Mongols burning village?
Junk science.
Just the Vikings. They were Westerners, and therefore solely to blame.
Not only that, those villians were the direct ancestors to George Bush thus it is George Bushes's fault :)
You're right, the reason the earth warmed is because the Vikings burned so many villages. The burning villages heated the clouds which caused rain to fall instead of snow, and soon the Vikings were growing grapes in Greenland.
With the warm weather, the Vikings found they could employ their slaves to grow grapes and other food. This left time for the Vikings to pursue other activities like counting their loot. Laying about while overseeing slaves, counting loot and ogling maidens was certainly a less dangerous line of work and more pleasurable.
The Vikings pursued this occupation for about 200 years. And since they weren’t burning villages anymore, the clouds didn’t heat up. So the earth stopped warming, the snow returned, the Earth got hit with a 300 year mini-ice age and the marauding Vikings sailed off into history.