Educational book on science of climate change with action items?
I recommend following two books. I am not sure it will answer all the questions you have mentioned but I think together they will answer most of them. 


The discovery of global warming by Spencer Weart http://www.worldcat.org/title/discovery-of-global-warming/oclc/51505599
The Weather Makers by Tim Flannery http://www.worldcat.org/oclc/80331702


Both the books are highly readable for non-expert audience. Both the books do good job in educating readers about scientific aspect of the problem without bogging down them with equations or technical jargon.  The first book's focus is on science aspect of the climate-change problem and told in highly engaging style, the second book's focus is on mitigation aspect in equally engaging style.