United Nations Environment Programme
http://www.unep.org/

The United Nations Environment Programme (UNEP) promotes sustainable development of the global environment. The UNEP website contains a wealth of information on sustainability, featuring publications, photos, videos, reports, news, and in-depth information on a host of thematic issues. The UNEP Global Environment Outlook (GEO) project can be accessed at http://www.unep.org/geo/.

Worldwatch Institute
http://www.worldwatch.org/

Worldwatch Institute conducts interdisciplinary research on key environmental, social and economic trends, providing up-to-date information through key publications, reports, and news releases. Publications older than 18 months are downloadable free of charge in PDF format.

Forum for the Future
http://www.forumforthefuture.org.uk/

Forum for the Future provides an extensive range of accessible on-line publications related to sustainable development in a broad subject area, including business, regional, rural, government, higher education, and technology. The publications include guidance, research, brochures, annual reports, reports, books, and web references.

Global Reporting Initiative
http://www.globalreporting.org/

The Global Reporting Institute (GRI) is an independent, multi-stakeholder institution collaborating with the United Nations Environment Programme (UNEP) in order to develop and disseminate globally acceptable Sustainability Reporting Guidelines.

Earth Trends: The Environmental Information Portal
http://earthtrends.wri.org/

Earth Trends is an information portal, featuring a comprehensive online searchable database, data tables, country profiles, and maps for a wide range of thematic environmental issues. As of December 2010, the World Resources Institute is no longer actively maintaining the Earth Trends website, however every data set, table and map on the website contain citations and hyperlinks to the original source of information, which may continue to update the information.