Cosmic ray effects on cloud cover and their relevance to climate change

A survey is made of the evidence for and against the hypothesis that cosmic rays influence cloud cover. The analysis is made principally for the troposphere.It is concluded that for the troposphere there is only a very small overall value for the fraction of cloud attributable to cosmic rays (CR); if there is linearity between CR change and cloud change, the value is probably ∼1%∼1% for clouds below ∼6.5km, but less overall. The apparently higher value for low cloud is an artifact.The contribution of CR to ‘climate change’ is quite negligible.

Research highlights
► No correlation is found between cosmic ray changes and the whole cloud cover.
► Influence of cosmic rays on the cloud cover in the troposphere is at the level of 1%.
► Cosmic rays have negligible effect on the global temperature and on climate.