.... "But the jury is still out on how
much sunspots can (or do) affect the Earth's climate. Times of maximum sunspot
activity are associated with a very slight increase in the energy output from
the sun. Ultraviolet radiation increases dramatically during high sunspot
activity, which can have a large effect on the Earth's atmosphere. From the mid
1600s to early 1700s, a period of very low sunspot activity (known as the
Maunder Minimum) coincided with a number of long winters and severe cold
temperatures in Western Europe, called the Little Ice Age. It is not known
whether the two phenomena are linked or if it was just coincidence. The reason
it is hard to relate maximum and minimum solar activity (sunspots) to the
Earth's climate, is due to the complexity of the Earth's climate itself. For
example, how does one sort out whether a long-term weather change was caused by
sunspots, or maybe a coinciding El Nino or La Nina? Increased volcanic
eruptions can also affect the Earth's climate by cooling the planet. And what
about the burning of fossil fuels and clear cutting rain forests? One thing is
more certain, sunspot cycles have been correlated in the width of tree ring
growth. More study will be conducted in the future on relating sunspot activity
and our Earth's climate."
"One interesting aspect of solar
cycles is that the sun went through a period of sunspot inactivity from about
1645 to 1715. This period of
sunspot minima is called the Maunder Minimum. Sunspots were measured during
this timeframe, although the more detailed, daily measurements began in 1749.
The "Little Ice Age" occurred over parts of Earth during the Maunder Minimum.
So the question remains, do solar minimums help to create periods of cooler than
normal weather, and do solar maximums help to cause drought over sections of
Earth? This question is not easily answered due to the immensely complex
interaction between our atmosphere, land and oceans. In addition, there is
evidence that some of the major ice ages Earth has experienced were caused by
Earth being deviated from its "average" 23.5 degrees tilt on its axis. The
Earth has tilted anywhere from near 22 degrees to 24.5 degrees on its axis. The
number of sunspots alone do not alter the overall solar emissions much at all.
However, the increased/decreased magnetic activity which accompanies sunspot
maxima/minima directly influences the amount of ultraviolet radiation which
moves through the upper atmosphere."
The Sun and Sunspots