A temporary phenomenon on the Sun's surface that is caused when intense magnetic activity creates an area of reduced surface temperature that is clearly visible as a dark spot. Some sunspots can be as large as 80,000 KM in diameter.
Their role in the debate
Sunspots are important to the climate debate because many skeptics believe that their behaviour correlates and perhaps causes global warming and cooling. For example, the Maunder (CE 1645-1715), Dalton (CE 1790-1830), and Sp Minimums (CE 1460-1550) were periods when sunspots were very rare. They were also periods of lower-than-average global temperatures.
An example skeptic argument
In the following video, the Lavoisier Group's Dave Archibald presents a version of the solar case for global warming.
1. Click here to read the essay where Archibald fully presents his thesis.
2. Click here to read David Archer's critique of Archibald's use of climate sensitivity.
3. Click here to read a n3xus6.blogspot.com critique of his use of temperature data.