1. EPA's Global Warming Site: the global warming website of the U.S. Environmental Protection Agency. The site provides links to information on the causes, impacts, and trends related to global climate change.
2. Intergovernmental Panel on Climate Change: the website for the Intergovernmental Panel on Climate Change, a United Nations-sponsored agency "to assess the scientific, technical and socio-economic information relevant for the understanding of the risk of human-induced climate change." Their website includes assessment reports detailing the relationships between human actions and global climate change.
3. Climate and Atmosphere: World Resource Institute's website on climate and atmosphere. The site includes several articles and case studies, including research on Clean Development Mechanisms.
4. United Nations Framework Convention on Climate Change: homepage for the United Nations Framework Convention on Climate Change. The site provides data on the climate change issue and information about the ongoing process of negotiating international agreements related to climate change.
5. Weathervane: a website sponsored by Resources for the Future devoted to climate change issues. The site includes several research papers on the trading of greenhouse gas emissions permits.