A collection of repeat photography of glaciers from the National Snow and Ice Data Center (NSIDC). The photos are taken years apart at or near the same location, and at the same time of year. These images illustrate how dramatically glacier positions can change even over a relatively short period in geological time: 60 to 100 years. Background essay and discussion questions are included.

With this simulation from the NASA Climate website, learners explore different examples of how ice is melting due to climate change in four places where large quantities of ice are found. The photo comparisons, graphs, animations, and especially the time lapse video clips of glaciers receding are astonishing and dramatic.

This visualization tool shows sea ice data from 1978 to the present. Selected data can be animated to show changes in sea ice extent over time. Data is added by the National Snow and Ice Data Center as it becomes available.

Global Forest Watch is an interactive, online forest monitoring and alert system that provides users globally with the information they need to better manage and conserve forest landscapes.

This is an interactive graph that involves records of ice cover in two Wisconsin lakes - Lake Mendota and Lake Monona - from 1855-2010.

This article and slide show from the New York Times, features several scientists from the University of Alaska, Fairbanks, who study the effects of thawing permafrost in Alaska.