Here’s an interesting video. It’s about Henrik Svensmark, a physicist at the Danish National Space Center and the guy that had a heart attack at Copenhagen.
youtube.com/watch?v=dKoUwttE0BA&NR=1
Basically he thinks that the atmosphere works a bit like a big cloud chamber. Cosmic rays enter the atmosphere and cause a shower of ions. The ions act as condensation nuclei around which a mist will form. So the amount of cosmic rays determines the cloud cover. Clouds reflect sunlight back into space and thus cool the earth. Now the sun’s magnetic field can shield the earth from cosmic rays and thus reduce cloud cover and cool it. This varies. Now the interesting thing is he believes this mechanism has a far larger effect on climate than CO2
He’s plotted cosmic ray levels versus cloud cover and got a good correlation.
Also as our solar system orbits the centre of the Milky Way galaxy every 250M years or so we pass through regions with lots of stars and regions with few. Since cosmic rays come from supernovae you have more cosmic rays as you pass through these regions. So every 150M years we experience more cosmic rays, more clouds and thus lower temperatures.
He’s done experiments too - something which is common in physics but must seem novel to climatologists. CERN is getting involved.
And he has papers published in peer reviewed journals
en.wikipedia.org/wiki/Henrik_Sve … blications
Though it took him longer than average - he’s about as popular as George Bush with the people that believe that CO2 is the main driver of climate and the head of the IPCC denounced his theory as ‘irresponsible’, rather like the Catholic Church did with Galileo. In fact he’s met with extreme hostility wherever he goes. Mind you, he survived his heart attack, and it seems like he’s convinced a few real scientists at CERN, the Physical Review Letters and the Royal Society his ideas have merit.