The Kill Order – by James Dashner (2012)

Imagine our world having disaster after natural disaster. First the sun unleashes solar flares over much of the planet, instantly killing a large segment of the human race and coating the earth with residual radiation. The climate becomes unstable, and natural disasters follow, causing additional loss of life. The food supply becomes very limited, and people are starving. To top it all off, a strange virus is intentionally released by an unknown group, causing insanity and death.