Datasets on the Earth's cryosphere, including permafrost, soil moisture, brightness temperature and more. Includes raw data, maps, and satellite images.

This page contians reports, assessments, federal research on global changes in the environment and implications for society. In addition it contains comprehensive links to every dataset used in the Third National Climate Assessment.

Data on climate indicators: temperature, carbon dioxide, snow, sea level, arctic sea ice, ocean heat, sun's energy, glaciers, and heat-trapping gases. Provides reusable climate data maps, GIS data locator, and state specific climate trends. Also has comprehensive guides from measuring and processing climate data to visualizing and using climate data in research.

Data from the EPA on major air pollutants and air quality monitoring. You can access national, regional, and local data for all measured pollutants which include particulate matter, nitrogen dioxide, and ground-level ozone.

U.S. Department of Energy's center for climate-change data and analysis. Includes climate variables, emissions data, and carbon cycling data.

Data sets from salinity to surface water temperature.

This site is the place to go if you need climate data, including precipitation, temperature, and other measures.

This web site allows you to search for datasets by data type, update time, state/territory, altitude and numerous other criteria.You can also narrow your search to groundwater, water quality,surface water, or water use.

Useful for assessing current drought conditions in the U.S.