The Little Ice Age is arguably what gave birth to the industrial revolution and helped along nationalism, revolutions, and the independence of the Americas.A milder one may bring more stagnation and less revolutions rather than greater innovation.Either the Scandinavians, Portuguese, Genoese or Venetians come upon the "North American" Continent a generation or two earlier than OTL (assuming navigational and ship building technologies gets pushed forward, as they probably would in TTL).
The Black Plague wouldn't have been so deadly, as Europeans wouldn't have been huddled up so close in their hovels for as much of the year. From there, the butterflies are endless.
I was thinking that the opposite might happen, as the warmer weather might increase human interaction and the movement of rats, fleas and air-borne germs in general.
Europe was already suffering from overpopulation with freezing weather, the strain may well to prove to be even larger if there's more food to go around and more mouths to feed. That sets things to be more of a disaster.Sure, but better weather means better crop yields means better nutrition means (generally) better health. So I'd say things will even out on the side of better resistance to plague.
Might not even be a black plague, as it might not make the key evolutionary changes that made it what it is if climate is different.The Black Plague wouldn't have been so deadly, as Europeans wouldn't have been huddled up so close in their hovels for as much of the year. From there, the butterflies are endless.
Greenlander Norse may survive.