The Earth Portal is an exciting and powerful new web-based tool for understanding and collaborating on environmental issues.  Its arena overlaps with that of sustainability, so some dimensions of the sustainability challenge will be addressed.  "The Earth Portal is a comprehensive resource for timely, objective, science-based information about the environment. It is a means for the global scientific community to come together to produce the first free, expert-driven, massively scaleable information resource on the environment, and to engage civil society in a public dialogue on the role of environmental issues in human affairs. It contains no commercial advertising and reaches a large global audience. The Earth Portal has three components (Go to http://www.earthportal.org/.):

1. The Encyclopedia of Earth, with over 2,000 articles, is produced and reviewed by 700 scholars from 46 countries.
2. The EarthForum provides commentary from scholars and discussions with the general public.