Climate fiction, or “cli fi,” can be a dreary genre. Storytellers like to make a grim business of climate change, populating their narratives with a humorless onslaught of death, destruction, drowned monuments, and starving children. Margaret Atwood is the conspicuous exception, somehow managing to tackle the subject, including these familiar elements, with deadpan wit and an irreverent playfulness, making it both more interesting and believable. The flood is coming, her MaddAddam trilogy promises, but there is hope.