Environmental alert: the good news, the bad news, and how you can help the planet

Earth day was celebrated for the first time more than 30 years ago, in 1970. And to help you celebrate Earth Day on April 22, Science World delivers an update on how the environment is faring. Some good news: Sewage-treatment laws have cleaned up many of the planet's lakes and rivers. And tougher air-pollution standards have begun to clear up the skies: Today, U.S. smokestacks churn out one fifth of the soot they did in 1970.

But scientists are still worried. From Los Angeles to New York, smoggy skies still cloud your view. One reason: Smog is created when sunlight reacts with chemicals spewed from cars and power plants. And today there are more cars crowding the highways than ever before.

Scientists believe the pollution from power plants and cars may have far worse consequences than hazy skies. The Day After Tomorrow, a movie premiering in May, looks at how pollution could lead to catastrophic climate change. Are the movie's scenes of devastation fact or fiction? Flip the page to find out.

Since the first Earth Day, many endangered species--like the bald eagle and gray wolf--have made a comeback. Turn to page 12 to discover how conservation efforts have brought the last remaining wild horses back from the brink of extinction. And if you're wondering how you can help the environment, check out "Buy a Better Earth" (see p. 16). You'll find out how the choices you make at the mall can make a difference to the planet.