Seven Billion Humans & Jared Diamond's "Collapse"

So various news organizations are reporting that our planet is now home to this mythical number of seven billion humans, mythical in that we don’t know that for sure, but it’s a good guess, and all its implications. I still regard Jared Diamond’s Collapse as one of the best big-picture nonfiction books I’ve read in a long time. He does a great job of analyzing how various cultures overused their resources, which led to their demise: the Mayans, the Easter Island natives, etc. Tim Flannery’s Here on Earth is in that vein as well, though focused on a myriad other topics besides societal collapse. Both are books we should all be reading, and heeding the warnings of. Here’s Jeffrey Sachs on the implications of 7 billion people:
http://www.cnn.com/2011/10/17/opinion/sachs-global-population/index.html?hpt=hp_c1