Levels of carbon dioxide in the atmosphere are fluctuating more than they used to from one season to another, according to observations from the HIPPO field project. This may be a sign of significant changes in northern ecosystems.

Drier ski slopes, reduced river flows, and increased wildfires can potentially discourage tourists from coming to Colorado. Should local officials and business leaders do more to plan for these impacts?

Carbon dioxide concentrations in the atmosphere have crossed a major threshold: 400 parts per million. Here are five key points on how carbon dioxide is affecting Earth’s atmosphere and the role we're playing in it.

The last month has seen a trail of smashed records across the central United States, as pulse after pulse of cold air careened down the Great Plains. How does this fit into the bigger picture of a warming U.S. climate?

Forests across western North America have been ravaged by the most extensive bark beetle attacks on record. Scientists are getting a better handle on what comes next—and the answers aren’t as straightforward as they expected.