Sea ice extent provided by the National Snow and Ice Data Center (NSIDC) is available from 1979–2022 for the Globe, Northern Hemisphere, and Southern Hemisphere. Snow cover extent provided by the Rutgers University Global Snow Laboratory (GSL) is available from 1967–2022 for the North America + Greenland, Northern Hemisphere, Eurasia, and North America. All anomalies are relative to the 1981–2010 average.