The Dalton Minimum followed the Maunder Minimum by something like 150 to 200 years. The Maunder Minimum was more severe and lasted longer, about 80 years compared to about 25 years for the length of the Dalton Minimum. It is difficult to choose the exact beginning, zenith, or end of these cool periods on Earth, particularly for the Maunder. We might choose the year 1820 to associate with the nadir of sunspot activity during the Dalton Minimum – slightly more than 180 years ago.
If the Sun’s magnetic cycle is sensitive to tidal forces, or other effects from the orbiting planetary mass, the number 180 may be magic. Scientists suggest, in a recent paper entitled “Does a Spin–Orbit Coupling Between the Sun and the Jovian Planets Govern the Solar Cycle?” (see the abstract here) that the combined effects of Saturn and Jupiter could induce magnetic cycle fluctuations in the Sun with a period of just about exactly 180 years.
As author Ian Wilson explained to Andrew Bolt from post Cooling coming:
It supports the contention that the level of activity on the Sun will significantly diminish sometime in the next decade and remain low for about 20 – 30 years. On each occasion that the Sun has done this in the past the World’s mean temperature has dropped by ~ 1 – 2 C.
Physicist Luboš Motl in this article states
The paper is effectively another peer-reviewed case for global cooling.
It is no small comfort that at least our deepest-thinking (skeptical) scientists are investigating Solar behavior and its impact on Earth’s climate. In the past, Solar magnetic behavior has been closely linked with very pronounced climate changes. Our government funded scientists however are busy figuring out how to pump carbon dioxide down abandoned mine shafts; how embarrassing.
Anthony Watts also blogs on this Global Cooling paper here.