sunspots and solar storms cause a shift in climate along with the polar shifts. NASA even confirmed this, and this is what 2012 is all about, polar shifts. don't expect it to be a doomsday kind of thing though.
co2 is natural and animals and humans breathe it out and plants thrive on it. there's been research that shows c02 lags behind temperature. the temperature of the earth rises and co2 follows the trend of the temp by a 500 year lag
