Aerosol nucleation induced by a high energy particle beam (abstract)The five Danish authors have used a 580 MeV electron beam to ionizine the atmosphere-like content of their chamber. The graphs show pretty clearly that the formation rate increases with the radiation. At O(10,000) ions per cubic centimeter, the nucleation rate approximately doubles while the existing data are compatible with a linear dependence.
Danish celebration of the paper (autom. transl. to EN)
Physics World (popular overview)
This is a very intense relationship. Note that the clouds in the atmosphere cool the Earth roughly by 10 times the warming induced by a CO2 doubling, so even 10% of the change of the cloud cover beats a doubled CO2. 10% of the change of the clouds corresponds to roughly 1,000 ions per cubic centimeter - in the regions of the atmosphere where the clouds are expected to form.
Of course, there are many other complicated mechanisms that decide about the aggregate amount of clouds but if the question is Do the cosmic rays influence the local and instantaneous nucleation rate, the answer is clearly Yes.
The Danish authors try to emphasize that the nature of the ionizing radiation is irrelevant which is why expensive colliders are a waste of money. Fortunately, the LHC - and even SPS - were not built just for the CLOUD experiment because that would be a waste of money, indeed. ;-)
Via Nigel Calder
Endeavour with AMS finally launched
With more than a two-week delay, the Alpha Magnetic Spectrometer was finally launched aboard the space shuttle Endeavour today. The launch was successful; see the first minute. AMS will also study the cosmic rays.
By the way, Roy Spencer has shown that the climate sensitivity is approximately 1 °C by looking at the 1955-2010 ocean heat content.