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 short video clip summarizes NOAA's annual State of the Climate Report for 2009. It presents a comprehensive summary of Earth's climate in 2009 and establishes the last decade as the warmest on record. Reduced extent of Arctic sea ice, glacier volume, and snow cover reflect the effects of rising global temperature.

This short video shows an example of melting alpine glaciers in the Austrian Alps (Goldberg Glacier). Disappearing alpine glaciers have social and environmental impacts, including the decline of fresh water supplies and contributions to sea level rise.

This video highlights a variety of climate change research initiatives from scientists at the University of Colorado, Boulder. It describes the changing dynamics of Antarctic ice sheets and the impacts of reduced Arctic sea ice. The video illustrates the excitement of this research through interviews and video clips of scientists in the field.

This video is the first of a three-video series from the Sea Change project. It features the field work of scientists from the US and Australia looking for evidence of sea level rise during the Pliocene era when Earth was (on average) about 2 to 3 degrees Celsius hotter than it is today.

This video considers the current estimates of sea level rise as possibly too conservative and discusses more recent data on ice melt rates coming from Antarctica and Greenland, showing rates of melt at up to 5 times as rapid. Scientists discuss what levels and rates of sea level rise have occurred in the past, including the Pliocene, which demonstrated 1m rise every 20 years.

In this video, a team of paleontologists, paleobotanists, soil scientists, and other researchers take to the field in Wyoming's Bighorn Basin to document how the climate, plants, and animals there changed during the Paleocene- Eocene Thermal Maximum (PETM). During this time a sudden, enormous influx of carbon flooded the ocean and atmosphere for reasons that are still unclear to scientists. The PETM is used as an analog to the current warming. The scientists' research may help inform our understanding of current increases in carbon in the atmosphere and ocean and the resulting impact on ecosystems.

This NBC Learn video features climate scientists doing their research on Mt. Kilimanjaro to study the climate of the past. The scientists put the recently observed changes on the glacier into perspective by comparing past climate fluctuations, stressing that the current observed rate of change is unprecedented.
Note: you will need to scroll down the Changing Planet video page to get to this video.

In this activity, students use Google Earth and team up with fictional students in Chersky, Russia to investigate possible causes of thawing permafrost in Siberia and other Arctic regions. Students explore the nature of permafrost and what the effects of thawing permafrost mean both locally and globally. Next, students use a spreadsheet to explore soil temperature data from permafrost boreholes and surface air temperature datasets from in and around the Chersky region for a 50-year time span.

This animation shows the Arctic sea ice September (minimum) extents from 1979-2014.

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