There's been lots of study done specifically on the Sun's 11-year (22-year if you count magnetic-flipping) cycle in order to see the progression of sunspot-activity. Basically, nowadays they can conclude that the mini ice-age of the 17th and 18th century that inspired the Icy Thames was indeed caused by a decrease in solar activity, not so much because of the Earth's climate.

They coined this the Maunder minimum, though they're not quite sure why a Sun that should be getting increasingly brighter (though achingly-slowly) over time suddenly slowed down its solar activity for a heightened period. What they are in agreement with though is that it was indeed the Sun that likely caused it, not climate.

by kirkus on 03/19/2010 02:05:25 AM EST