There's an Earth Day celebration in store for Mrs. Green's class, and her students are working on important reports. They're out to discover all the ways the climate is changing and what can be done to help Mother Nature. One by one they pick their subjects: Freddy will cover food supply (a subject close to his heart) and Derek takes recycling because he thinks it's about riding a bike. Hubie gets stuck with water pollution, a very big problem for rivers and lakes. When he learns what's happening to streams and oceans all over the planet, Hubie decides to turn over a new leaf — a green one!

Funny and upbeat cartoons pepper the story with earth facts, zany jokes, and wacky side characters (and make sure to check out Eric's ecology riddles at the back!).