The
Little Ice Age (LIA) was a period of cooling that occurred after the
Medieval Warm Period (Medieval Climate Optimum). While it was not a true
ice age, the term was introduced into the scientific literature by
François E. Matthes in 1939. It has been conventionally defined as a period extending from the sixteenth to the nineteenth centuries, or alternatively, from about 1300 to about 1850, although climatologists and historians working with local records no longer expect to agree on either the start or end dates of this period, which varied according to local conditions.