Dr. Pfeffer is a glaciologist at the Institute of Arctic and Alpine Research and professor of civil, environmental, and architectural engineering at the University of Colorado at Boulder. His research areas include the mechanics and dynamics of glaciers and heat and mass transfer in snow. He has worked on glaciers for 30 years, traveling to Alaska, Arctic Canada, Greenland, Antarctica, and mountain locations in North America and Europe. He has done fieldwork on Alaska’s Columbia Glacier for two decades. Tad is also active in photography and photogrammetry of glaciers and landscapes, using imagery for both description and analysis of glacier changes. In addition to scientific publications, his photographic work has appeared in exhibitions in the Boulder/Denver area, in American Scientist, GEO (Germany), Geotimes, BBC television productions, and in the movie and book, An Inconvenient Truth, by Nobel laureate Al Gore. Tad’s book, The Opening of a New Landscape: Columbia Glacier at Mid-Retreat, was published by the American Geophysical Union in December 2007.