Michael Asher (Blog) - September 1, 2008 8:11 AM
Drop in solar activity has potential effect for climate on earth.
The sun has reached a milestone not seen for nearly 100 years: an entire month has passed without a single visible sunspot being noted.
The event is significant as many climatologists now believe solar magnetic activity – which determines the number of sunspots -- is an influencing factor for climate on earth.
According to data from Mount Wilson Observatory, UCLA, more than an entire month has passed without a spot. The last time such an event occurred was June of 1913. Sunspot data has been collected since 1749.
SNIP
But this year -- which corresponds to the start of Solar Cycle 24 -- has been extraordinarily long and quiet, with the first seven months averaging a sunspot number of only 3. August followed with none at all. The astonishing rapid drop of the past year has defied predictions, and caught nearly all astronomers by surprise.
In 2005, a pair of astronomers from the National Solar Observatory (NSO) in Tucson attempted to publish a paper in the journal Science. The pair looked at minute spectroscopic and magnetic changes in the sun. By extrapolating forward, they reached the startling result that, within 10 years, sunspots would vanish entirely. At the time, the sun was very active. Most of their peers laughed at what they considered an unsubstantiated conclusion.
The journal ultimately rejected the paper as being too controversial.
SNIP
[...] In the past 1000 years, three previous such events -- the Dalton, Maunder, and Spörer Minimums, have all led to rapid cooling. One was large enough to be called a "mini ice age". For a society dependent on agriculture, cold is more damaging than heat. The growing season shortens, yields drop, and the occurrence of crop-destroying frosts increases.
SNIP
Other researchers have proposed solar effects on other terrestrial processes besides cloud formation. The sunspot cycle has strong effects on irradiance in certain wavelengths such as the far ultraviolet, which affects ozone production. Natural production of isotopes such as C-14 is also tied to solar activity. The overall effects on climate are still poorly understood.
What is incontrovertible, though, is that ice ages have occurred before. And no scientist, even the most skeptical, is prepared to say it won't happen again.
SNIP
http://www.dailytech.com/Sun+Makes+History+First+Spotless+Month+in+a+Century/article12823.htm 
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