Climate Change - Variation in Sun Spot Activity
huge magnetic storms that show up as dark (cool) areas on the suns surface
when there are more sunspots, the sun is emitting more energy, hence, the amount of energy incident on the earth increases
so, one could imagine warmer climate during a sun spot maximum and cooler climate during a minimum.
oogle sunspots to find out what they look like
sun spot period is about 11 years