"In the past 1000 years, three previous such events -- the Dalton, Maunder, and Spörer Minimums, have all led to rapid cooling. One was large enough to be called a "mini ice age". For a society dependent on agriculture, cold is more damaging than heat. The growing season shortens, yields drop, and the occurrence of crop-destroying frosts increases..."

 

http://www.dailytech.com/Sun+Makes+History+First+Spotless+Month+in+a+Century/article12823.htm