Humans and the Greenhouse Effect – Climate Institute
The greenhouse effect - British Geological Survey
Greenhouse effect - Energy Education
What is the natural greenhouse effect and how have humans impacted the atmosphere? – HBK Portal
Consequences of the greenhouse effect - Iberdrola
Overview of Greenhouse Gases | US EPA
Explained: Greenhouse gases | MIT News | Massachusetts Institute of Technology
Human Activities are Intensifying the Earth's Natural Greenhouse Effect - Maasch - Yale's Climate Connection - Climate Change Institute - University of Maine
Climate Change: Science and Impacts Factsheet | Center for Sustainable Systems
The greenhouse effect - British Geological Survey
Greenhouse Gases | MIT Climate Portal
Greenhouse gases: Causes, sources and environmental effects | Live Science
Human Influence on the Greenhouse Effect | GlobalChange.gov