Answer:
Medieval Warm Period - this was a period of warmer weather in the Northern hemisphere that lasted from 950 to 1250 CE. In Europe, this period allowed the Norse to colonize Iceland and Greenland, which, while still very cold and mostly barren, were warm enough to allow the cultivation of a few crops.
In the rest of the continent, a wide variety of crops could be grown, for example, grapes were cultivated in Southern England.
Little Ice Age - the Little Ice Age also affected the Northern hemisphere, and lasted from 1300 to 1850 approximately. During this period, average temperatures fell across Europe and North America.
In Europe, the effects were frequently devastating. Greenland had to be abandoned because it became to cold, and Iceland essentially survived on fish and game. In winters that were particularly cold, famines spread and killed thousands or even hundreds of thousands.
