G581: Earth. Gliese 581g, #3

Earth lies devastated and empty. Over 99.6% of the population have succumbed to the deadly ESH virus. More have perished in the civil wars and anarchy that followed. With humanity on the brink of extinction, and most made infertile by the virus, newly-elected President Madeline Chen is forced to make unthinkable choices - robbing millions of their basic human rights to ensure mankind's survival. But suddenly, mankind faces the opposite problem.
A 14-kilometer asteroid is hurtling towards the planet - one larger than the one that wiped out the dinosaurs. Survival requires escaping off-world before impact, or huddling for safety deep beneath the Earth - and there's only limited space either way. Earth's 14 million survivors have suddenly gone from too few to far too many.   G581: Earth is the third novel in Christine D. Shuck's immersive Gliese 581 science fiction series.
It blends science fiction with achingly human, character-driven stories proven by recent headlines to be terrifyingly plausible - making this book a compelling choice for those who appreciate both Margaret Atwood's The Handmaid's Tale and Arthur C. Clarke's The Hammer of God.