After all the billions of dollars recently spent on climate change research – with the predetermined conclusion that humans are the cause of recent warming – solar activity remains the best indication of earths climate.
Furthermore, the effects of human activity cannot be distinguished form natural phenomena.
Solar Activity and Climate (K.Lassen)
“70-90 years oscillations in global mean temperature are correlated with corresponding oscillations in solar activity. Whereas the solar influence is obvious in the data from the last four centuries, signatures of human activity are not yet distinguishable in the observations.”
So, how do sunspots affect earths climate?
Sunspots are associated with high energy activity from the sun. solar flares and other kinds of solar mass ejections are associated with sunspots. The energy radiated from these events are huge, but they are also in the UV frequencies (higher than visible light), so we cannot feel them as heat (lower than visible light).
no sunspots, no high energy solar activity.
The high energy radiation reaches earth (if it is sent in our direction), causes auroras, it can interfere with electronics and radio waves, causing CB radio and SW radio blackouts. Other than these effects, we dont notice much about these high energy events. It also strengthens the ionosphere. The ionosphere acts as a kind of radiation shield. When it is stronger, less cosmic rays can enter the earths atmosphere to the level of clouds. it seems that cosmic rays are vital for cloud formation. Less clouds can form, and more of the heat fraction of the suns energy can reach the earths surface. In this way, sunspots regulate the amount of solar radiation that can reach the surface of the earth, controlling the earths climate.
no high energy solar activity, more cloud cover, cooler climate
The effect of cloud cover on earths climate requires further research. its one thing to understand that increased cloud cover reduces the heating of the earths surface, but measurements of albedo (cloud coverage) have only started recently. there is not enough data to make a correlation over many climate cycles. Futher data is required to measure the actual scale of the effect of cloud cover on the climate.