This video is part two of a seven-part National Academies series, Climate Change: Lines of Evidence. The video outlines, with the use of recent research and historical data, how we know that the Earth is warming.

This audio slideshow examines the changes in the ecosystem that will occur to the Arctic due to increasing temperatures and disappearing sea ice.

This video follows biologist Gretchen Hofmann as she studies the effects of ocean acidification on sea urchin larvae.

In this activity, students will use oxygen isotope values of two species of modern coral to reconstruct ambient water temperature over a four-year period. They use Microsoft Excel, or similar application, to create a spreadsheet of temperature values calculated from the isotope values of the corals by means of an algebraic equation. Students then use correlation and regression techniques to determine whether isotope records can be considered to be good proxies for records of past temperatures.

This is a real-time map of current drought conditions in the US, which can be zoomed to the state level, with access to many more resources at that level. Some of these include the National Drought Regional Summaries and animations of historical data.

This video is the third in a three-part series by the Sea Change project, about scientists' search for Pleiocene beaches in Australia and elsewhere to establish sea level height during Earth's most recent previous warm period. This segment features the research of Jerry Mitrovica, Harvard geophysicist.

This gallery of ten temperature graphs shows global temperatures on different timescales from decades (recently measured temperatures) to centuries (reconstructed) to millions of years (modeled from ice cores).

This classroom resource is a combination of 3 visualizations and accompanying text that illustrate how 3 key natural phenomena - cyclical changes in solar energy output, major volcanic eruptions over the last century, and El Nino/Nina cycles - are insufficient to explain recent global warming.

In this activity, students examine the effects of hurricanes on sea surface temperature using NASA data. They examine authentic sea surface temperature data to explore how hurricanes extract heat energy from the ocean surface.

In this video from the Polaris Project Website, American and Siberian university students describe their research on permafrost.