War girls
(Book)

The year is 2172. Climate change and nuclear disasters have rendered much of earth unlivable. Only the lucky ones have escaped to space colonies in the sky. In a war-torn Nigeria, battles are fought using flying, deadly mechs and soldiers are outfitted with bionic limbs and artificial organs meant to protect them from the harsh, radiation-heavy climate. Across the nation, as the years-long civil war wages on, survival becomes the only way of life. Two sisters, Onyii and Ify, dream of more. Their lives have been marked by violence and political unrest. Still, they dream of peace, of hope, of a future together. And they're willing to fight an entire war to get there. --from Amazon.