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For any form of publication, please include the link to this page and give the cartographer/designer credit (in this case Hugo Ahlenius, UNEP/GRID-Arendal)
National Research Council (2006). Surface Temperature Reconstructions for the Last 2,000 Years. National Academies Press, Washington D.C.
Uploaded on Tuesday 21 Feb 2012
Temperatures over previous centuries from various proxy records
Hugo Ahlenius, UNEP/GRID-Arendal
Evidence from tree rings and other temperature proxies suggests that during the previous 500 years global temperatures were 1.0ºC cooler than those of the 20th century during a period roughly from 1300 to 1870 – known as the Little Ice Age. While overall temperatures during the Little Ice Age were cooler than now, there was much year-to-year variability and some warm periods. The coldest part of the Little Ice Age, from 1645 to 1715, was also a time of minimum sun spots, referred to as the Maunder minimum. Although there is a correspondence in time, the causal connection between sun variability and Earth climate is a subject of ongoing debate. It is clear, however, that the 20th century was recovering from the average colder temperatures of the 19th century and earlier.