Earth sciences and environmental data repositories

• DataOne Goddard Earth Sciences Data and Information Services Center
• IRI/LDEO Climate Data Library - Climate-related datasets from the International Research Institute for Climate and Society at Columbia University
• Marine Geoscience Data System (MGDS) - A data portal, hosted at the Lamont-Doherty Earth Observatory (Columbia University), for a number of NSF-supported marine research programs
• NASA Warehouse Inventory Search Tool (WIST) - Locate earth science data from NASA and affiliated centers
• National Climatic Data Center (NCDC) - Meteorology and paleoclimatology
• NCAR/UCAR Community Data Portal - Climate and weather datasets and visualization software from the National Center for Atmospheric Research and the University Corporation for Atmospheric Research
• National Oceanographic Data Center (NODC)- World-wide marine environmental and ecosystem data
• National Center for Atmospheric Research Computational & Information Systems Library
• USGS National Satellite Land Remote Sensing Data Archive - Note that some data access is fee-based
• GEON - Portal for datasets and visualization tools
• National Snow and Ice Data Center (NSIDC) - Cryospheric datasets from ground field reseach and satellites

GIS and geography data repositories

• Geodata.gov - One-stop for federal, state and local geographic data
• GeoCommons.com GIS file repository and finding tool
• Federal Geographic Data Committee - Provides access to the National Spatial Data Infrastructure (NSDI) Clearing House Network and the geodata.gov portal
• National Geographic Data Center - Archive of datasets