Orphan’s Destiny

I am currently reading Orphan’s Destiny by Robert Buettner. Orphan’s Destiny takes place after the book Orphanage, where an interplanetary war was initiated by the “Slugs” upon humanity by bombardment from space using big chunks of rock. Many of Earth’s cities were destroyed but even near misses devastated our environment by sending tons of dirt and ash into the atmosphere to block the sun.