Survival by Daniel Powell. free at
B&N and
Smashwords
The year is 2209, and the hour has grown late for the human race. Famine and disease have drastically compounded the misery of a warming planet, and steps have been taken to cull the human population through a process called Labor--a gauntlet of chaos and destruction all men must survive in order to earn the privilege to become fathers. It's Bryan Norton's time. Can he survive Labor?