>How much of the warming is down to CO2? Contentious, again - e.g. see this book for an argument of how we could explain much if not all of the warming down to various natural cycles: [...]

Unfortunately, you have your conclusion in this sentence wrong: the natural cycles barely affect the global temperature increase, found in [0]. You should stick to scientific literature for scientific facts instead of some quack.

[0] -- http://ipcc.ch/report/ar5/wg1/