The Last Sanctuary by William R. Lowry
Congratulations Bill Lowry!
The Last Sanctuary is a story of devastation, survival, and hope. Set in the near future, devastation occurs when climate-change-induced disasters trigger a nuclear war that kills most of the Earth's population. A small group of survivors, having planned for the possibility of such an event by building an ark as a mobile repository housing the DNA of the world's plant and animal species, searches for a new home in a world that has been nearly destroyed.
The story is rich in settings and characters. The main character is a restless adventurer who travels across the American continent to the ark project, witnessing climate devastation as he goes. He joins the ark crew, a diverse group of people from all walks of life, just before the nuclear war and thus becomes part of an endeavor much larger than himself. They search for refuge in the Pacific Ocean and settle on an island where they establish and then protect the world's last sanctuary.