The Year of the Flood by Margaret Atwood

The sun brightens in the east, reddening the blue-grey haze that marks the distant ocean. The vultures roosting on the hydro poles fan out their wings to dry them. the air smells faintly of burning.

The waterless flood - a man-made plague - has ended the world. But two young women have survived: Ren, a young dancer trapped where she worked, in an upmarket sex club (the cleanest dirty girls in town); and Toby, who watches and waits from her rooftop garden. Is anyone else out there?