I'm gona get strait to the point. I recon global warming is due to the weakening of the earths magnetic field. It stands to reason. Don't take my word forit that the earths mgnetic field is weakening, the link below is a documentry from NOVA saying exactly that, with loads of evidence and NOVA aren't exactly alex jones conspiracy theorist, on the contrary very mainstream NOVA - Earth's Invisible Shield In short they say the main effects we would see of a weakening field is warming and a rise in skin cancer. Well both are supposedly happening, you can search google all day and find examples of this. Im no scientist, don't even have a degree, so if you have any evidence to the contrary then go ahead.