Alaska’s Columbia glacier has retreated rapidly over the last four decades. This false-color image was taken in July 2014. Photo: Lauren Dauphin / NASA Earth Observatory
Alaska’s Columbia glacier has retreated rapidly over the last four decades. This false-color image was taken in July 2014. Photo: Lauren Dauphin / NASA Earth Observatory

By Carolyn Gramling
10 December 2019

SAN FRANCISCO (Science News) – A mesmerizing new series of images shows the retreat of Alaska’s Columbia glacier over the last 47 years in gorgeous, excruciating detail. The images were presented December 10 at the American Geophysical Union’s annual meeting.

Landsat satellites operated by NASA and the U.S. Geological Survey have been collecting images of Earth since 1972, making the program the longest space-based observer of Earth’s land surface. That record provides an unprecedented opportunity to watch the movement of ice through time: the flow and rapid retreat of glaciers, the calving off of large chunks of ice and when landslide debris gets caught up in the action, says glaciologist Mark Fahnestock of the University of Alaska Fairbanks.

Alaska’s Columbia glacier began rapidly retreating around 1980, and its leading edge has moved more than 20 kilometers inland. These images, captured by the joint NASA / U.S. Geological Survey Landsat satellites, were stitched together into a video to show the glacier’s dynamic evolution from 1972 to 2019. Video: Mark Fahnestock / University of Alaska Fairbanks

To illustrate the dynamic dance of the ice over time, Fahnestock and colleagues selected annual Landsat images of several of Alaska’s glaciers, including fast-retreating Columbia glacier on Prince William Sound, and turned them into mini movies. The images show how Columbia glacier has retreated by more than 20 kilometers since about 1980.

See how an Alaskan glacier has shrunk over time