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 series of visualizations show the annual Arctic sea ice minimum from 1979 to 2010. The decrease in Arctic sea ice over time is shown in an animation and a graph plotted simultaneously, but can be parsed so that the change in sea ice area can be shown without the graph.

This is an interactive website that provides descriptive information and data related to ten key climate indicators. These climate indicators and related resources show global patterns and data that are intuitive and compelling teaching tools.

In this video segment, a team of scientists seeks evidence to support their hypothesis that atmospheric warming -- either now or in the past -- may explain why water has formed beneath the West Antarctic ice sheet, causing ice streams that flow much more quickly than the rest of the ice sheet. This phenomenon has important implications for potential sea level rise.

This video examines the thawing of permafrost due to changes in climate and shows examples of the impacts that warming temperatures have on permafrost in the Arctic, including the release of the greenhouse gas methane. Dramatic results are shown, including sink holes forming on the landscape and beneath buildings, roads, and other infrastructure, causing some communities to relocate.

In this video, the mountain pine beetle problem is explained by two scientist. Their research investigates the beetle and how climate change is impacting its spread.

This NOAA video discusses how the ocean absorbs the increased amount of carbon dioxide released into the atmosphere, thereby changing the pH and buffering action of the ocean. These changes in pH are impacting calcifying organisms, such as corals and shellfish, and related food chains and ecosystems.

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.

This interactive visualization provides a clear, well-documented snapshot of current and projected values of several climate variables for local areas in California. The climate variables include observed and projected temperatures, projected snowpack, areas vulnerable to flooding due to sea level rise, and projected increase in wildfires. The projected values come from expert sources and well-established climate models.