America's Skies and Waters: Cleaner Than Ever

Activists are reluctant to crow, since climate change remains a huge threat. But over the past three decades America's rivers, lakes, and skies have been transformed. Acid-rain levels have dropped 60 percent since the early 1990s; air quality has improved 91 percent since 1980 in terms of lead content. The Hudson River "is much, much cleaner than it's been in 100 years," says Riverkeeper's Phillip Musegaas. Greens can be a little less blue.