Relationship of Lower-Troposphere Cloud Cover and Cosmic Rays: An Updated Perspective

Abstract

Abstract An updated assessment has been made of the proposed hypothesis that galactic cosmic rays (GCRs) are positively correlated with lower-troposphere global cloudiness. A brief review of the many conflicting studies that attempt to prove or disprove this hypothesis is also presented. It has been determined in this assessment that the recent extended quiet period between solar cycles 23 and 24 has led to a record-high level of GCRs, which in turn has been accompanied by a record-low level of lower-troposphere global cloudiness. This represents a possible observational disconnect, and the update presented here continues to support the need for further research on the GCR–cloud hypothesis and its possible role in the science of climate change.