The Institute for Global Environmental Strategies focuses on sustainable development, the atmosphere, land formations such as volcanoes, and energy. Web resources are integrated along with offline resources and activities. The lessons themselves are exceptionally complete and a variety of alternative assessment events are provided for every lab and activity.
The Earth Times is a not-for-profit publication. The contents are edited daily.
There are regional Earth Times sites, like the one in San Diego, that look at issues on a local, rather than global, basis.
Earth Day Network, designed for students, reports on activities centered about Earth Day, an annual celebration.
The World Bank specializes in sustainable development all around the world, especially in underdeveloped countries. This site, mostly of interest to high school students, includes the charts, maps, and photos.
As the Web has entwined our world, new sites are emerging with excellent references for International Studies, a necessary complement to environmental studies. An example can be found at the International Affairs Resources web site.
Many Internet and Web Yellow Page-type books and search services hold pointers to various general international references. The quality varies and some time can be dissipated searching for good sites.