A Green History of the World is the foremost book in this category. This global history succeeds in covering a lot of important areas. It is thorough and begins at the beginning. This would be useful to an eager student looking for the big picture. It would also be useful, like Southwick's global ecology book, for constant reference throughout a class.
Many themes tie into it.
This is what prevents me from ravin in a berzerk manner about this book. It is good, but perhaps not truly great. I will continue reading it in the hopes of changing my opinion.