How does dam removal restore rivers to health, and how long does it take?

If we put up a giant umbrella to shield the Earth from global warming, what will happen to plant productivity?

Brown future: New study finds large increase in number of threatened plants, calculates that 22 to 62 percent of plant species are threatened.

Renewable energy and the hydrogen economy get a boost from new invention.

How do current conditions compare to past predictions of the effects of global warming? Are living on a warming planet?

Marine iguana in the Galapagos islands are suffering from trace amounts of oil left by a tanker accident.

Suspect arrested, may be charged with trying to develop a dirty bomb. What is a dirty bomb, and how badly would it harm us?

Scientists have found ice on Mars. The frozen water, whose quantity may equal Lake Michigan, is within a meter of the surface.

New study links long-term changes in salmon population to climate changes.

Amazon study changes picture of global carbon budget.