Nigel Calder writes on his Calder Updates blog there is now more proof that cosmic rays influence the earth’s climate. Calder co-wrote The Chilling Stars, with Henrik Svensmark, who conducted the initial experiments on cosmic ray cloud formation. The CLOUD experiment at CERN gave additional support to the theory that cosmic ray aid cloud formation. But, not all scientist were convinced, pointing to the lack of conditions that would lead to the growth of additional aerosols in the atmosphere. Now Svensmark and two of his colleagues in Denmark’s National Space Institute in Copenhagen, Martin Enghoff and Jens Olaf Pepke Pedersen have submitted a paper to Physical Review Letters demonstrating that there is a growth mechanism.
Abstract: In experiments where ultraviolet light produces aerosols from trace amounts of ozone, sulphur dioxide, and water vapour, the number of additional small particles produced by ionization by gamma sources all grow up to diameters larger than 50 nm, appropriate for cloud condensation nuclei. This result contradicts both ion-free control experiments and also theoretical models that predict a decline in the response of larger particles due to an insufficiency of condensable gases (which leads to slower growth) and to larger losses by coagulation between the particles. This unpredicted experimental finding points to a process not included in current theoretical models, possibly an ion-induced formation of sulphuric acid in small clusters.
A preprint is available on arXiv here: http://arxiv.org/abs/1202.5156v1
The observational evidence is now more secure:
Supernova remnants → cosmic rays → solar modulation of cosmic rays → variations in cluster and sulphuric acid production → variation in cloud condensation nuclei → variation in low cloud formation → variation in climate.
It is important to note that sunspots, or the lack of sunspots, influences the “solar modulations of cosmic rays” Fewer spots allows more cosmic rays to encourage cloud formation and influence the climate. More spots excite the earths magnetosphere which can deflect cosmic rays, resulting in fewer clouds and more sunshine, thus a warmer earth. As the spots vanish, more cosmic rays –> more clouds –> a cooler earth. We can expect more cooling if the sunspots totally vanish some where beyond 2015 as predicted by Livingston and Penn. Their paper is here: Livingston-penn-2010