  The problem of the contribution of cosmic rays to climate change is a
continuing one and one of importance. In principle, at least, the recent
results from the CLOUD project at CERN provide information about the role of
ionizing particles in 'sensitizing' atmospheric aerosols which might, later,
give rise to cloud droplets. Our analysis shows that, although important in
cloud physics the results do not lead to the conclusion that cosmic rays affect
atmospheric clouds significantly, at least if H2SO4 is the dominant source of
aerosols in the atmosphere. An analysis of the very recent studies of
stratospheric aerosol changes following a giant solar energetic particles event
shows a similar negligible effect. Recent measurements of the cosmic ray
intensity show that a former decrease with time has been reversed. Thus, even
if cosmic rays enhanced cloud production, there will be a small global cooling,
not warming.
