Originally released in 2007 as a television program.

Special features of this DVD: additional scenes (ca. 10 min.).

Narrator, Demetri Goritsas ; camera, Jason Ellson and David Swan ; editor, Chris Roberts ; music, Neil Maccoll and George Taylor.

Narrator, Demetri Goritsas.

The History Channel answers the question: After 650 million years of climate change, is global warming simply a naturally occurring phenomenon, or the result of human activity? Arctic ice is melting, sea levels are rising and glaciers are shrinking at alarming rates. And the Earth is getting unmistakably warmer. But is this vast potentially catastrophic climate change the result of human behavior? Or is it simply the Earth's natural cycle of warming and cooling periods that have occurred since the planet formed? An in-depth study of the science behind this controversial hot-button issue. Scientists explore the skies to examine the warming effects of the sun and dig deep into the Earth to study continental movement and the volatile activity at the planet's core. Experts speculate on how natural events including volcanic eruptions and massive meteor impacts have affected temperatures and weather systems over the planet's 600-million-year history.

DVD.

Closed captioned for the hearing impaired.