The Spörer Minimum is a period of low solar activity which lasts from about 1420 to 1570 (some say 1450 to 1550).
It occurs before sunspots are directly observed, and will be discovered instead by analysis of the proportion of carbon-14 in tree rings, which is strongly correlated with solar activity.
It is named for the German astronomer Gustav Spörer.Like the subsequent Maunder Minimum, the Spörer Minimum coincides with a time when Earth's climate is colder than average.
This correlation has generated hypotheses that low solar activity produces cooler than average global temperatures, though a specific mechanism by which solar activity results in climate change has not been established.
