A new paper in Nature Geoscience shows that solar grand minima do indeed cause cooling of the climate in Europe. Around 2800 years ago, one of these Grand Solar Minima, the Homeric Minimum, caused a distinct climatic change in less than a decade in Western Europe. The forcing mechanisms still remain unclear but the evidence that solar effects are significant and cannot be ignored are mounting and persuasive. Now as we enter (or have already entered) a new solar minimum it remains to be seen as to whether this (Landscheidt?) Minimum will be a grand minimum to compare with the Maunder Minimum. In any event a period of global cooling seems likely.
In contrast, the evidence for any anthropogenic effects on climate is still non-existent though political and alarmist theories abound. There is as yet no direct evidence that man-made carbon dioxide emissions has any significant effect on global warming.
Regional atmospheric circulation shifts induced by a grand solar minimum by Celia Martin-Puertas, Katja Matthes, Achim Brauer, Raimund Muscheler, Felicitas Hansen, Christof Petrick, Ala Aldahan, Göran Possnert & Bas van Geel
The k2p blog 