On the possible connection between cosmic rays and clouds

TL;DR

This paper examines the potential link between cosmic rays and cloud cover, finding little evidence for a causal connection and estimating that at most 20% of low clouds could be influenced by cosmic rays.

Contribution

It provides an analysis challenging the causal connection between cosmic rays and cloud cover, quantifying the maximum possible influence of cosmic rays on low clouds.

Findings

Anticorrelation between low and middle clouds suggests no causal link with cosmic rays.

If low clouds are influenced by cosmic rays, the effect is limited to about 20%.

No significant causal connection established between cosmic rays and cloud cover.

Abstract

Various aspects of the connection between cloud cover (CC) and cosmic rays (CR) are analysed. We argue that the anticorrelation between the temporal behaviour of low (LCC) and middle (MCC) clouds evidences against causal connection between them and CR. Nevertheless, if a part of low clouds (LCC) is connected and varies with CR, then its most likely value averaged over the Globe should not exceed 20% at the two standard deviation level.