There have only been sunspots visible on the sun for 133 days in the past year. The last three solar cycles have become progressively weaker. There is now a legitimate concern that because there have been several very weak solar cycles in succession, that we could tip over into another Grand Solar Minimum (GSM).
This potentially developing GSM could be something similar to the Maunder Minimum that lasted from 1645 to 1715. (Or even longer, depending the climatologist you consult.) In northern Europe, the Maunder Minimum was famous for decades of brutal winters in the deepest part of what is commonly called The Little Ice Age. This climate aberration caused huge crop failures that may have triggered or exacerbated the Anglo-Spanish War, the Second Northern War, the Austro-Turkish War, the War of Devolution, the Franco-Dutch War, two Russo-Turkish Wars, the Great Turkish War, the Nine Years War, and countless smaller civil wars and pillaging. Notably, the River Thames in England froze quite deeply, in 1677. (As shown in today's illustration.) It was also during the Maunder Minimum that the Vikings abandoned all of their settlements in Greenland.