More carbon dioxide in the air doesn’t necessarily mean more growth for trees, and the increasing risk of wildfires and drought has major consequences, as an interactive map shows.

The Colorado River provides water and electricity to 40 million people in the western U.S., but falling water levels threaten both of those resources.

Agreements negotiated a century ago to share water on Western rivers among states are showing their age in a time of water scarcity.

Human migration due to droughts will increase by at least 200% as we move through the 21st century, research indicates.

Flash droughts don't last long, but can be disastrous. A new study shows they're more frequent and coming on faster, likely due to climate change.

How hot is too hot, and how dry is too dry, for the Earth's forests? Research on decades of dying trees offers an answer.