At some time in the past I blogged about the various solar cycles that come into play when the temperature of the Earth is involved, but I hadn't been paying attention to the most important of those cycles, the Sunspot Cycle. The Sunspot Cycle has been shown to correlate closely with the Earth's climatic cycles, and there is a known causal link between the two. This cycle has also been known for hundreds of years, and astronometers have expanded their knowledge as time has passed. That is to say ...