The fine folks at The Hockey Schtick link to an interesting paper in Advances in Space Research:
New paper predicts Dalton-like solar Grand Minimum by mid-21st century
A paper published today in Advances in Space Research finds the current solar cycle has "an unprecedented solar minimum long duration 2006-2009 that led to a prolonged galactic cosmic ray (GCR) recovery to the highest level observed in the instrumental era." The authors believe a long-term decrease in solar activity is underway to a Dalton-like Grand Minimum in the middle of the 21st century.
"These happenings affected our empirical predictions for the key parameters for the next two sunspot cycles (they may be progressively less active than [current] sunspot cycle 24) but it enhanced support for our prediction that solar activity is descending into a Dalton-like grand minimum in the middle of the twentyfirst century"
If so, and if man-made CO2 has any significant warming effect, we ought pump out CO2 as fast as possible to offset a potential 2nd Little Ice Age in the mid-21st century.
If Svensmark's cosmic ray theory theory of climate proves correct, this will further amplify the global cooling effect of low solar activity, due to increased cloud nucleation from increased galactic cosmic rays.
Dalton Minimum? Here:
The chart shows the observed sunspots but sunspots are an excellent proxy for solar flux. From the above link:
The Dalton Minimum was a period of low solar activity, named after the English meteorologist John Dalton, lasting from about 1790 to 1830[1] (solar cycle 4 to solar cycle 7). Like the Maunder Minimum and Spörer Minimum, the Dalton Minimum coincided with a period of lower-than-average global temperatures. During that period, there was a variation of temperature of about 1°C.[2]
The precise cause of the lower-than-average temperatures during this period is not well understood.
Wikipedia's pro-AGW bias is shining through loud and clear - the low temperature is very well understood. The sun was not putting out as much heat.
