At the end of the book the child's true identity is discovered, and the bad guys get their just deserts.

With clever pricing, clearer ownership and a bit of co-operation, water scarcity can be alleviated. If humanity fails to act, it will get just deserts.

The deserts just make a particularly clear case exactly because they do get cold so fast at night, and snakes can't hide out in wooded or grassy areas.