BASE: Bielefeld Academic Search Engine one of the best and most comprehensive tools for locating open-access books, journals, dissertations, and other scholarly sources available worldwide.
Websites
AGI: American Geosciences Institute
Berkley Earth Surface Temperature Analysis of land surface temperature records going back 250 years
Future Science Opportunities in Antarctica and the Southern Ocean (National Academies Press)
Geology News and information about geology
Goddard Earth Sciences Data and Information Services Center
NASA Earth Observatory: Global Maps
NOAA Earth System Research Laboratory
NOAA's National Weather Service
National Geophysical Data Center
National Hurricane Center
National Oceanic and Atmospheric Administration
Natural Resources Conservation Service
National Snow and Ice Data Center
Scott Polar Research Institute "The world's most comprehensive polar Library and Archives".
Unisys Weather Hurricane Tropical Data
Water Resources of the United States (USGS)
Woods Hole Oceanographic Institution
USGS National Geologic Lexicon Database: Geolex Geolex, a free index to publications on named geologic rock units in North America
USGS National Geologic Map Database A free index to maps and geospatial data related to the geological sciences.
Digital Libraries
MetaLib, a service of the Catalog of U.S. Government Publications (53 government databases, subject gateways, digital repositories and e-journals)
National Science Digital Library
OAIster More than 19 million digital resources from over 1,000 organizations developed by the University of Michigan.
Science Portal (U.S. Government)
USGS Library (Geological Survey)
WorldWideScience.org is a global science gateway comprised of national and international scientific databases and portals.