4. There is a still very poor understanding of the correlation between low sunspot activity and cooling temperatures.[60][61] During the period 1645–1715, in the middle of the Little Ice Age, there was a period of low solar activity known as the Maunder Minimum. The Spörer Minimum has also been identified with a significant cooling period between 1460 and 1550.[62] Other indicators of low solar activity during this period are levels of the isotopes carbon-14 and beryllium-10.
5. The Little Ice Age brought colder winters to parts of Europe and North America. Farms and villages in theSwiss Alps were destroyed by encroaching glaciers during the mid-17th century.[17] Canals and rivers inGreat Britain and the Netherlands were frequently frozen deeply enough to support ice skating and winter festivals.[17] The first River Thames frost fair was in 1607; the last in 1814, although changes to the bridges and the addition of an embankment affected the river flow and depth, hence diminishing the possibility of freezes.
![Medieval warm period ,[object Object]](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)