A period between about 1350 and 1860 during which the global climate became generally harsher and there was a worldwide expansion of glaciers. The effects have been recorded in the Alps, Norway, and Iceland, where farm land and buildings were destroyed, and in many other parts of both hemispheres. There were times of especial severity during this period, e.g. the early 1600s when glaciers were particularly active in the Chamonix valley, in the French Alps.