
11 days
Yes. We’re consuming lots of natural resources at a prodigious rate, like topsoil, phosphorous, and even fresh water — never mind fossil fuels. It seems fairly clear that the planet cannot support a population of 7 billion humans for very long (on a geological timeframe), so either we’re in a civilizational bubble that will pop or we’re going to have to come up with another round of magical technologies à la the Haber Process to keep the bubble going…

Dan Moren’s Galactic Cold War series might be a good fit. Like Scalzi, it’s very soft sci fi, with a somewhat military bent (spies, in this case) and well-written characters.
Also, if you liked Old Man’s War, I actually thought Scalzi’s Interdependency series was better so you might enjoy that.