SCIENCE

Condition Critical (State Of The Planet)

An exclusive look at a U.N. assessment of Earth's ecosystems shows they are strained to the limit

Vanishing Before Our Eyes (Biodiversity)

Not since an asteroid smacked Earth 65 million years ago have animal and plant species died out so fast. We have no idea what we're losing.

Extinctions Past And Present (Biodiversity)

Famous for finding fossils of early humans, the author took up the cause of conservation. Here he champions a global fund for wildlife.

SOCIETY

The Big Crunch (Population)

Birthrates are falling, but it may be a half-century before the number of people--and their impact--reaches a peak

Asphalt Jungle (Sprawl)

A global land rush is gobbling up the space and resources needed for agriculture and wildlife. Only the cockroaches are thrilled.

TECHNOLOGY

ALSO IN THIS ISSUE

Unleash the Rivers (Freshwater)

Dams are responsible for some of the worst environmental tragedies in history. We're starting at last to take some down.

Taking The Long View (Reflections)

Space travel gave us a new look at Earth. Now we need a new sense of time.

SPECIAL SECTION

Star Power Lights The Way (Celebrity Heroes For The Planet)

As an Earth Day headliner, Leo joins a legion of highly visible eco-advocates

A Global Green Deal (The Future)

The bad news is that we have to change our ways--and fast. Here's the good news: it could be a hugely profitable enterprise.

A Princely Pioneer (Heroes For The Planet)

The campaigns against urban sprawl and genetic engineering get a royal boost

PEOPLE