As recently as 1000 years ago, the Northern Hemisphere was relatively warm and dry. During this time, vineyards flourished, and wine was produced in England, indicating warm, dry summers, and the absence of cold springs. It was during this tranquil period of several hundred years that the Vikings colonized Iceland and Greenland. In the 13th and 14th centuries, Europe experienced extreme weather variations, which caused cold winters, hot summers, great floods, and great droughts.