Encylopedia of Life (EOL) is working to put all of our knowledge of the species on earth in a free electronically available encyclopedia. Both experts and amateurs are encouraged to contribute information and pictures on species, and their ranges.
Encylopedia of the Earth (EoE) is a free electronic reference about the Earth. It is reviewed by experts but the content on natural environments, and their interaction with society is contributed by a wide variety of scholars, educators, and practitioners. The content is presented in a style intended to be useful to students, educators, scholars, professionals, as well as to the general public.
Climate Central provides both background material and up to date news on climate and weather, energy and sea-level rise. It has excellent graphics and an interactive map on how sea level changes in storms may impact coastal communities.
Real Climate is a discussion site for climate scientists. It includes discussions on recent findings. It is aimed largely for scientists but an informed citizen will find the discussions interesting and enlightenting. For a more basic introduction the site contains up to date links to other sites.
Other basic climate information sites include:
NCAR: Weather and climate basics
Center for Climate and Energy Solutions: Global Warming basics
Wikipedia: Global Warming
NASA: Global Warming update
National Academy of Science: America’s Climate Choices (2011)
Global Warming FAQ (Tom Rees)