Dynamics of Cats

hey, there is a little black spot on the sun today (click to embiggen)

but it is very little.
We are now in a somewhat unusual protracted and low solar minimum - the Sun has cycled, the few small spots seen have reversed from the previous cycle - but this is getting a wee bit worrying.

Current Solar Cycle - from NOAA (click to embiggen)

The current minimum is starting to get people worried about whether the Sun is gone back into a protracted low activity phase, like during the Maunder minimum, and the associated "Little Ice Age".

A protracted solar minimum would lead to reduced radiative forcing, by about 0.3 W/m². This corresponds to about 0.3 C cooling, and would on a time scale of decades partially mask anthropic warming - of course when the sunspots come back, so does all the warming, modulo buffering by the heat capacity of the oceans etc.

Mann et al have a nice paper on modeling the Medieval Climate Optimum/Little Ice Age transitions around the 12th and 17th centuries respectively. The paper recovers both the net warming/heating and hemispheric patterns, under the assumption of solar forcing variation.
The "Little Ice Age" has a pronounced hemispheric asymmetry - cooling is stronger in the north, especially continental US and Eurasia, partly offset by mid-Atlantic warming.
Not being a climatologist, I am free to speculate that this is some plausible combination of more ocean in the south to provide thermal buffering, and the Earth being in a "little summer", with perihelion near mid-winter in the northern hemisphere accentuating the cooling

Good news is we might start getting regular deep snow by Thanksgiving, bad news is not only would the weather get worse - more N.A and Eurasia winters like the current, but all the heating would come back when the sun goes active again with more rapid short term warming.

That is if the Sun stays quiet for any extended period.

Interesting times.
Mann et al. Science 326 1256 27 Nov '09 (sub)