Review of statement by Center for Sun-Climate Research
States that varying activity of the sun is the largest contributor to natural climate changes. Increases in solar activity correlate to decreases in cloud cover on earth. This could be due to shielding of cosmic rays from exploding stars. Increase in solar activity produces more shielding. Cosmic rays may seed the formation of clouds when the rays collide with air molecules producing ions which form condensation nuclei. Since clouds cool the earth by reflecting sunlight, less clouds means warming climate. Solar activity has been high in the twentieth century. The effect has been above average temperature. The twentieth century condition has been: high solar activity, high shielding of cosmic rays, less clouds, and more warming of earth by the sun.
Alan Detwiler, author of Thrivers In An Uncertain Future; bio at