Climate Change Reference Guide and Glossary
At the heart of climate change is the greenhouse effect, in which molecules of various gases trap heat in Earth’s atmosphere and keep it warm enough to support life. Carbon dioxide and other “greenhouse gases” (GHGs) are an important part of Earth’s
natural cycles, but human activities are boosting their concentrations in the atmosphere to dangerous levels. The result is rising global temperatures and an unstable climate that threatens humans, economies, and ecosystems.