Sorry, but the scientific paper cited has a number of errors. It belittles the Little Ice Age as a minor event. The cooling era destroyed European settlements in Greenland. Legend says they slowly froze and starved as their animals could no longer graze. Reportedly, only one survivor took a ship east. Iceland was cut off for so long genetic drift destroyed them. Visitors from Europe found no living persons -- skeletons of giants, dwarves and pinheads.
England, once renown for its wine -- retired Roman soldiers traveled there to claim free land for farming and vinyards. Same for northern Europe (present day Germany). As the vinyards failed, they grew grains for beer and whiskey. Many starved because of the crop failures. The Dutch canals froze over. Ice skating became popular. That rarely happens now.
Volcanic activity is cited as the cause of most of the cooling -- but not where the active volcanoes were located. It takes a near Krakatoa sized events for centuries to cause such wide spread cooling. Even Krakatoa caused only one year with no summer.