This short video, is the fifth in the National Academies Climate Change, Lines of Evidence series. It focuses on greenhouse gases, climate forcing (natural and human-caused), and global energy balance.

This simulation allows the user to project CO2 sources and sinks by adjusting the points on a graph and then running the simulation to see projections for the impact on atmospheric CO2 and global temperatures.

This graph, based on key ice core data sets and recent monitoring programs, shows the variations in concentration of carbon dioxide (CO2) in the atmosphere during the last 400,000 years.

This multi-part activity introduces users to normal seasonal sea surface temperature (SST) variation as well as extreme variation, as in the case of El NiÃo and La NiÃa events, in the equatorial Pacific Ocean. Via a THREDDS server, users learn how to download seasonal SST data for the years 1982 to 1998. Using a geographic information system (GIS), they visualize and analyze that data, looking for the tell-tale SST signature of El Nino and La Nina events that occurred during that time period. At the end, students analyze a season of their own choosing to determine if an El NiÃo or La NiÃa SST pattern emerged in that year's data.

This video is the second of a three-video series in the Sea Change project, which follows the work of Dr. Maureen Raymo, paleogeologist at Columbia University's Lamont-Doherty Earth Observatory, who travels with fellow researchers to Australia in search of evidence of sea level that was once higher than it is today.

This is a simulation that illustrates how temperature will be affected by global CO2 emission trajectories. It addresses the issue that even if global emissions begin to decrease, the atmospheric concentration of CO2 will continue to increase, resulting in increased global temperatures.

This video shows 15 years of data obtained via Polar-orbiting satellites that are able to detect subtle differences in ocean color, allowing scientists to see where there are higher concentrations of phytoplankton - a proxy for the concentration of chlorophyll in the ocean.

In this activity, students compare carbon dioxide (CO2) data from Mauna Loa Observatory, Barrow (Alaska), and the South Pole over the past 40 years to help them better understand what controls atmospheric carbon dioxide. This activity makes extensive use of Excel.

This video features University of Wisconsin-Madison researcher John Magnuson, who studies the ecology of freshwater systems. He explains the difference between weather and climate using data on ice cover from Lake Mendota in Madison, WI. Analysis of the data indicates a long-term trend that can be connected to climate change.

This video features research conducted at University of Colorado's Institute of Arctic and Alpine Research, which studies isotopes of hydrogen trapped in ice cores to understand climate changes in the past.

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