The Kyoto Treaty, signed in 1997 to combat global warming, went into effect Wednesday. Gwen Ifill leads a discussion on the newly enacted treaty and the U.S. decision not to participate.

Scientists around the world are looking to coral reefs for the next big medical breakthrough. Correspondent Betty Ann Bowser explores the potential of these "rainforests of the sea" to provide the raw materials for life-saving drugs in the second of…

Some scientists are concerned that overfishing, pollution and global warming are killing parts of the world's coral reefs. Correspondent Betty Ann Bowser explores what is being done to save the reefs in part one of a two-part series.

Russia's state Duma on Friday ratified the Kyoto Protocol, which aims to fight global warming, giving the global pact a good chance of being enacted and boosting Russia's chance at joining the World Trade Organization.