An anonymous reader writes "What has been argued for years by various scientists and "Global Warming Deniers" is that there was a strong correlation between sunspot activity and global temperature in spite of the irradiance from the sun not increasing.
We now have a potential explanation
Researchers have managed to replicate the effect of cosmic rays on the aerosols in the atmosphere that help to create clouds. Henrik Svensmark, a weather scientist in Denmark, said the experiments suggested that man's influence on global warming might be rather less than was supposed by the bulk of scientific opinion.
Cosmic rays — radiation, or particles of energy, from stars, which bombard the Earth — can create electrically charged ions in the atmosphere that act as a magnet for water vapour, causing clouds to form.
Dr Svensmark suggests that the Sun, at a historically high level of activity, is deflecting many of the cosmic rays away from Earth and thus reducing the cloud cover.
Some how this will be the oil companies fault I'm sure"