A survey of possible effects of long-lasting absence of solar activity on climate and some speculations on possible mechanisms

This paper deals with the prolonged lack (or existence) of solar activity, such as the Maunder or Spoerer minima, since considerable climatic changes barely occur within a shorter time interval. For this aim, first the possible influences of the present-day 11-yr solar cycle are considered for higher atmospheric regions, and found scarcely to be responsible for inducing climatic changes. On the other hand, solar activity-generated changes of the solar parameter in the visible spectrum are estimated too. The results of these simple considerations indicate that the external manifestations of the solar cycle hardly can cause observable change in the tropospheric weather (and so the long-lasting solar quiets seem not climatically significant), and seem indirectly to support the possibility, that the Milankovitch mechanism plays an important role in forcing the ice-age oscillations at least during the Quaternary period. Besides it can be concluded that greater (>= 0.1%, measured from satellite platform) solar parameter variations cannot be in close connection with the known forms of solar activity, which suggest that the possible, significant secular solar luminosity changes could be generated deep inside the Sun and/or could not be closely related to the sunspot cycle. (Auth.)