Already one year ago, in April 2015, scientists warned that the cooling effect by aerosols had been exaggerated (see our blog article “ Director of the Hamburg Max-Planck-Institute for Meteorology: Aerosols cool less than previously assumed“). This appears to have been confirmed further. Within the scope of the CLOUD Project at CERN, scientists have found more indications that the aerosol effect in the models must corrected strongly downwards.”

Although the product of alpha pines occurred only in concentrations of one molecule per one trillion air molecules, they effectively contributed to cloud formation as the experiment showed. Through the influence of ions from cosmic rays, the effect increases even 10 to 100 times.”

In the artificial atmosphere, scientists directed a beam of positively charged particles, so-called pions, which were generated by a Proton-Synchrotron. With this they simulated the effect of cosmic rays, which are constantly penetrating into the atmosphere. This stream of particles caused the organic molecules to ball up into approximately 2-nanometer size particles. More measurements confirmed that these volatile organic compounds grew further to form efficient condensation nuclei. In parallel the scientists underpinned the mechanism with computer models. ‘These results for me are the most important so far that the CLOUD experiment yielded so far,’ said Kirkby.”

The experiment also showed that the nucleation rate rose by one or two orders of magnitude under the influence of cosmic rays. ‘This allows one to conclude that cosmic rays had a greater role on aerosols and cloud formation in preindustrial times than under today’s relatively dirty conditions,” said Paul Winkler of the Department of Aerosol Physics and Environmental Physics at the University of Vienna.”