The Environmental Dataset Gateway (EDG) provides a one-stop to discover and access EPA's Open Data resources. The EDG contains metadata records contributed by EPA Regions, Program Offices, and Research Laboratories that links to geospatial and non-geospatial resources (e.g., data, Web services, or applications). Unrestricted information that is contributed to the EDG is shared with Data.gov.

FAOSTAT provides free access to food and agriculture data for over 245 countries and territories and covers all FAO regional groupings from 1961 to the most recent year available.
Data areas: Agriculture, Emissions, Fertilizer, Forestry, Land use, Pestizides, Population

Climate data from the Intergovernmental Panel on Climate Change (IPCC) Assessment Reports

The ORNL DAAC offers Earth science data for global change research and Earth systems studies. Sponsored by NASA, the archive includes field data, remote-sensing data, imagery, and the results of ecosystems modeling. The ORNL DAAC archives regional and global data about climate, environmental processes, nutrient cycles, stream and river discharge, soil properties, canopy chemistry, net primary productivity, land use change, and vegetation. Such data are vital to understanding and predicting how Earth systems function. The data can be used to validate remotely sensed information, as well as to improve and validate the output of ecosystem models.
Data areas: Arctic Ecosystems, Biomass, Carbon Cycle, Climate, Cryosphere, Fire, Forestry, Hydrology, Land use, Soils, Vegetation