Jeremy Jackson said scientists know how to save ocean reefs and fisheries. But doing it is a matter of political will. He said the importance of success stories is that they provide a model and inspiration.
Snow geese are spending winters 200 miles farther north than usual, and purple finches are a whopping 400 miles more to the north of their usual winter hangout.
Since 1980, scientists have believed a meteorite impact in the Yucatan caused a mass extinction of species, including the dinosaurs. But geologist Gerta Keller of Princeton disagrees.
The East Antarctic ice sheet may be at the end of the Earth, says geophysicist Donald Blankenship, but it's much more important than its distance implies. Hear Blankenship talk about his concern over melting ice sheets.
As a nation we're relatively well-endowed with water. But environmental scientist Peter Gleick warns, "the problem is that regionally we see growing scarcity. We see growing conflicts over water."