Svensmarks "SKY II-projekt"

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.

"The case for cosmic rays and their impact on clouds looks better than ever."

"diverse reconstructions of past climate change have revealed clear associations with cosmic ray variations recorded in Cosmo genic isotope archives, providing persuasive evidence for solar or cosmic ray forcing of the climate..
Studies of changes in cloud cover 5 to 10 days after Forbush Decreases appear to now, after some false starts, confirm the link between cosmic rays and clouds as do changes in cloud cover over the 11 year solar cycle.
Cosmic rays also match well with temperature over millenial and century time scales.
The CERN experiments do nothing more than prove the physical and chemical mechanisms involved at this stage but are likely to produce more conclusive results in the next few years.
To most reasonable people this would be enough.

"I think it's an incredibly worthwhile and overdue experiment," says Piers Forster, a climatologist at the University of Leeds, UK, who studied the link between cosmic rays and climate for the latest scientific assessment by the International Panel on Climate Change. But for now at least, he says that the experiment "probably raises more questions than it answers".

So in conclusion it has been shown that an increase in
ion-induced nucleation survives as the clusters grow into
CCN sizes in direct contrast to the present neutral ex-
periment and current theoretical expectations. It is pro-
posed that an ion-mechanism exists which provides a sec-
ond significant pathway for making additional H2SO4, as
a possible explanation of the present experimental find-
ings. Irrespective of the detailed mechanism leading to
the results presented here they provide a possibly impor-
tant missing piece of the puzzle as to why responses in
aerosol to variations in ionization have been seen in cloud
properties.