U.S. Climate Resilience Toolkit: One stop shop to federal data regarding climate change. Topics include human health, water, food resilience, energy infrastructure, coastal flooding, and more.
NOAA Maps and Data: Just like it sounds! Includes GIS data locator, dataset gallery, and "Climate Dashboard."
NASA (Climate Change and Global Warming): Vital signs, facts, graphs, and more from NASA.
Globalchange.gov (U.S. Global Change Research Program): Direct site to federal climate data resources as well as select datasets associated with the Third National Climate Assessment.
