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.

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.

This interactive displays how climate variables are changing over time (temperature, CO2, Arctic sea ice, sun's energy, sea level, etc.) in graphical form. Students can easily examine over 50+ years of archived data.

Using US Drought Monitor data and its classification system, this interactive tool tracks drought in the continental US by county, from 2000 to the present.

Here students use data from the NOAA carbon dioxide monitoring sites, such as Mauna Loa, to graph the Keeling Curve for themselves on large sheets of paper. Each group graphs one year, and the graphs are joined at the end to reveal the overall upward trend. The explanation describes the carbon cycle and how human activities are leading to the overall trend of rising carbon dioxide.