Like Henrick Svensmark's cosmic ray theory. He reckons the sun's magnetic field has been about double its average for a 100 years or so. This has caused the CR flux to miss the earth. In more normal times those rays, so he claims, unaffected by a weaker Sun MF hit the atmosphere and react with it as a stratus cloud seeder.
These clouds are a pretty good "umbrella" being dense to incoming ultraviolet radiation and would, in times when the sun's MF is closer to average, have a cooling effect greater than the present observed average rise in GW (0.6 degrees centigrade).
The models of the true believers do not allow for cloud cover. So they hate him and have tried to show his science or maths or both aren't what true believers allow. He and others have issued rebuttals of the critiques. The Europeans are evaluating his experimental work. viz irradiating a simulated atmospheric mixture with cosmic rays to see if indeed stratus cloud seeding occurs.
It does not disprove the CO2 theory but provides another explanation for the small average rise in earth temperature over the last 100 years or so.
