What was the Maunder minimum?

The Maunder minimum was an unexplained period of drastically reduced sunspot activity that occurred between 1645 and 1715.12

While solar cycle activity typically waxes and wanes every 11 years, English astronomer Edward Walter Maunder identified that very few sunspots were observed during this 70-year interval. Although initially dismissed by contemporaries as a result of poor observation, the phenomenon was later confirmed by American astronomer John Allen Eddy in 1976 using historical records and carbon-14 analysis in tree rings.12

This period coincided with the coldest phase of the Little Ice Age, characterized by severe winters and advancing glaciers in the Northern Hemisphere. While the correlation is suggestive, the physical mechanism linking solar activity to Earth's climate remains unknown, and these episodes do not definitively prove that lower sunspot numbers cause global cooling.12