One hour presentation to the American Geophysical Union by Dr.Richard Alley, Professor of Geosciences at Penn State. Very informative and worth the watch.
http://www.agu.org/meetings/fm09/lectures/lecture_videos/A23A.shtmlDr. Alley's fields of expertise include glaciology, climate change and ice core analysis, and he has done extensive field work on ice sheets and the climate in Antarctica and Greenland. Dr. Alley also has been involved with the National Academy of Sciences and the Intergovernmental Panel on Climate Change, or IPCC, and was one of the prime movers in the latest IPCC report in 2007 that described the state of climate change on Earth and the role of human activities.
"The history of climate is recorded in ice," said Dr. Alley, whom Penn State honored in 2000 as an Evan Pugh professor. "Most of the potential for changing sea levels is in ice sheets."
Sea levels are on the rise, and there is "strong scientific evidence that humans are at least partially responsible" for the changes in climate, he said. "Almost all pieces of land ice are shrinking."