How do sunspots contribute to global warming?
Sunspots are generally related to the suns activity. It cycles over an 11 year period, you generally get more sunspots corresponding with the higher output. This can cause some changes to climate on earth. Additionally, the angle of the earth to the sun along with eccentricities in orbit lead to variations in the amount of radiation that reaches earth. These are called the Milancovich cycles and were the predominant climate forcing features in the past. They can be closely modeled against past climate change, particularly the patterns of glacial / interglacial. These natural cycles are included in all modern models of climate change, which is why we are so sure greenhouse gas emissions are the driving force behind current change.
