ONE YEAR after everyone made such a fuss about Earth Day 1990, Mother Nature is in worse shape than ever. There is hope, though. Today's elementary and middle school kids are some of the feistiest environmental activists around, and several new books help encourage their passion for conservation.
* ''Going Green: A Kid's Handbook to Saving the Planet,'' by John Elkington, Julia Hailes, Douglas Hill and Joel Makower (Puffin paperback, $8.95, ages 8 and up). This book starts out with a no-nonsense explanation of how we've gotten the Earth into this mess. You don't need to be a chemist to understand the authors' description of the greenhouse effect. Full-color cartoons Tony Ross add to the explanations, and there are ''Amazing Facts'' like this one scattered throughout: ''If every American recycled just one-tenth of their newspapers, we would save about 25 million trees a year.''
The facts and figures give kids enough ammunition to pester parents about their wasteful ways. Kids are encouraged to go shopping with their folks to make sure they buy groceries in recycled -- and recyclable -- packaging. There is a checklist to use at home, at school and in the community. Get your neighbors to sign a petition to start curbside recycling, for example. Or organize students to request that your school district stop using chemical fertilizers and pesticides on school grounds.
At the back of the book there's a bibliography plus a list of organizations that offer memberships or information packets on things kids can do to save the planet. Adults may resist at first -- it's a pain to separate garbage or car pool to work -- but their children and grandchildren can be powerful lobbyists.
* ''Rain Forest Secrets,'' by Arthur Dorros (Scholastic Hardcover, $13.95, ages 6-9). One of the most informative looks at the balance of nature in rain forests, this non-fiction book is never boring. It's filled with facts and new vocabulary words that kids will pick up quickly. And instead of focusing only on the tropics, Dorros also introduces readers to the temperate rain forests, or old-growth forests, of the Pacific Northwest. He shows how that ecosystem is just as precious as that of the Amazon region.
* ''The Great Kapok Tree,'' by Lynne Cherry (Harcourt Brace Jovanovich, $14.95, ages 5-9). This is a rare treat -- a sort of ''docudrama'' that imparts a message without too much preaching. Cherry's story is as appealing as her ripe artwork.
A man is sent into the rain forest to chop down the giant Kapok tree. After he whacks away for a while, he falls asleep, and all of the creatures in the rain forest come up to the sleeping man, one by one. They whisper in his ear, explaining how every living thing relies on the rain forest. Although there's a happy ending, the maps on the endpapers show how rain forests are shrinking all around the world.
* ''Crinkleroot's Guide to Walking in Wild Places,'' by Jim Arnosky (Bradbury Press, $13.95, ages 4-10). Because kids shouldn't spend all their time worrying about saving the world, here's a book about how to enjoy a simple walk in the woods, taking advantage of the beauty we're trying to preserve.
Parents who grew up in the city should appreciate Crinkleroot's advice on how to remove ticks, identify poison ivy and treat bee stings. Kids will want to get out and explore, and Crinkleroot might even convince their parents that it's OK to walk barefoot along a stream bank.
* ''The Year of the Panda,'' by Miriam Schlein, illustrated by Kam Mak (Thomas Y. Crowell, $12.95, ages 8-12). This is a story based on fact about a young boy who lives on a farm in China. Lu Yi saves an orphaned baby panda he finds in the hills above his home, and later he finds out that the Chinese government is offering a reward for anyone who rescues a panda.
The endangered animals are starving because the bamboo in the mountains, its sole source of food, is dying. The baby panda has become Lu Yi's pet, but he agrees to give it to government veterinarians who have set up a rescue center for the pandas. The reward money helps Lu Yi's parents, but his real payoff comes when the scientists at the center ask him to come work there as a student aide. He's thrilled, and readers find out that kids can make a difference.