e. Based on evidence from tree rings, other natural records, and scientific observations made around the world, Earth's average temperature is now warmer than it has been for at least the past 1,300 years. Average temperatures have increased markedly in the past 50 years, especially in the North Polar Region.

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 animation depicts global surface warming as simulated by NCAR's Community Climate System Model (CCSM) Version 3. It shows the temperature anomalies relative to the end of the 19th century, both over the entire globe and as a global average. The model shows the temporary cooling effects during 5 major volcanic eruptions and estimates future temperature trends based on different amounts of greenhouse gas emissions.

This is a classroom activity about the forcing mechanisms for the most recent cold period: the Little Ice Age (1350-1850). Students receive data about tree ring records, solar activity, and volcanic eruptions during this time period. By comparing and contrasting time intervals when tree growth was at a minimum, solar activity was low, and major volcanic eruptions occurred, they draw conclusions about possible natural causes of climate change and identify factors that may indicate climate change.

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.

In this activity, students chart temperature changes over time in Antarctica's paleoclimate history by reading rock cores. Students use their data to create an interactive display illustrating how Antarctica's climate timeline can be interpreted from ANDRILL rock cores.

This video segment describes climate data collection from Greenland ice cores that indicate Earth's climate can change abruptly over a single decade rather than over thousands of years. The narrator describes how Earth has undergone dramatic climate shifts in relatively short spans of time prior to 8000 years ago. The video and accompanying essay provide explanations of the differences between weather and climate and how the climate itself had been unstable in the past, with wide variations in temperature occurring over decadal timescales.

This NASA animation of the Five-Year Average Global Temperature Anomalies from 1881 to 2009 shows how temperature anomalies have varied in the last 130 years. The color-coded map displays a long-term progression of changing global surface temperatures from 1881 to 2009. Dark red indicates the greatest warming and dark blue indicates the greatest cooling.

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.

This short video examines the recent melting ice shelves in the Antarctica Peninsula; the potential collapse of West Antarctic ice shelf; and how global sea levels, coastal cities, and beaches would be affected.