A study of Scots Pine tree rings preserved in lakes in Northern Finland found that the dendrochonological evidence of the warmest and coldest 250 year periods AD 931-1180 and AD 1601-1850 coincided with the generally recognized Medieval Warm Period and Little Ice Age.

A variety of cycles were observed, especially a 60 year cycle attributable to the North Atlantic thermohaline circulation occurring during the Medieval Warm Period, and a strong 80-95 year cycle overall.

Based on the study’s data, a warmest period 2010-2020 followed by a coolest period 2050-2060 could be projected.

From the Astute Bloggers via Seneca the Younger.