This video describes the role that dendrochronology plays in understanding climate change, especially changes to high elevation environments at an upper tree line. Dendrochronologists from the Big Sky Institute sample living and dead trees, describe how correlations between trees are made, and explain how tree cores record climate changes.

This video explores the work of environmentalist John Hart, a Professor of Environmental Science at U.C. Berkley. In the Rocky Mountains of Colorado, Dr. Hart has established an experimental laboratory in which he has artificially created and maintained a 3-degree increase in surface temperature of a plot of land, and documented the impact on plant species occupying the plot.

This video highlights a team of scientists who work on reconstructing the mass extinction that occurred 250 million years ago, the end of the Permian Period. This event wiped out the majority of life on our planet, resetting the evolution of life. Clues suggest that deadly bacteria might have set off a chemical chain reaction that poisoned the Permian seas and atmosphere.

In this video segment, adapted from a student video produced at Northwest Indian College in Bellingham Washington, Native American elders discuss the impact of climate change on salmon populations and the importance of restoring balance in the natural world.

In this video, students learn that the Exxon Valdez oil spill in Alaska in 1989 was not the sole cause of the decline of species in the local ecosystem. Rather, an explanation is posited for why some animal populations were already in decline when the spill occurred. Many of these animals share a common food: the sand lance, a fish whose populations have shrunk with the steady rise in ocean temperature that began in the late 1970s.

A short video that discusses how changing climate is affecting the population of AdÃlie penguins.

This video and accompanying essay review the impacts of rising surface air temperatures and thawing permafrost on ecosystems, geology, and native populations in Alaska.

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.

This is a photo essay linked to a New York Times story about climate-related stressors on forests -- including mountain pine beetles, forest fires, forest clearance, and ice storms -- and the importance of protecting forests as an important carbon sink.

This is a collection of five short videos that show how climate change is affecting fishing, native populations and access for the oil and gas industry in the Arctic. The videos include personal reflections by writers Andrew C. Revkin and Simon Romero, scientists, and residents about their experience of the impacts of the climate change in the Arctic.

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