The link between cosmic rays and cloud formation ~ Center for Sun-Climate Research

For more than 20 years, satellite records of low-altitude clouds have closely followed variations in cosmic rays (diagram 1). Just how cosmic rays take part in cloud-making appeared in the SKY experiment, conducted in the basement of the National Space Institute. Electrons set free in the air by passing cosmic rays help to assemble the building blocks for cloud condensation nuclei on which water vapour condenses to make clouds

Cosmic-ray Intensities and Low-level Cloud Formation
1. Red depicts cosmic-ray intensities and blue, the low-level cloudiness

via Center for Sun-Climate Research.

Comment:~ It is important to bear in mind that the researchers do not exclude man-made warming, but treat this as one of several factors that influence climate change:

“The significant contribution from solar activity variations to global temperature increase does not, however, exclude other contributions to the rising global temperature, natural as well as human. However, taking into account the large uncertainty associated with the estimated human contribution, a good research-based estimate of the range of natural climate variations is an essential information. The NSI is focused on establishing the best possible and scientifically based evaluation of the size of solar induced effects on climate.”