We’ve known for some time that the Greenland ice sheet is melting at an alarming rate. But a new study from Northwestern University and the University of Copenhagen found that thousands of Greenland’s peripheral glaciers have entered a new and widespread state of rapid retreat.
In their research, the team used satellite imagery and rarely seen historical aerial photographs of Greenland’s coastline to map the thousands of glaciers that are not part of the island’s vast central ice sheet. To complete the study, the researchers removed the distortion of the terrain and used georeferencing techniques to identify the exact locations where the photos were taken. The unique data allowed the researchers to document and compare over a thousand glaciers and how they have changed over the past 130 years.
According to Yarrow Axford, senior author of the Northwestern study, some of the historic photos were taken from open-cockpit aircraft during the first Greenland mapping missions. “These old pictures extend the dataset from before the satellite era, when widespread observations of the cryosphere were rare. It is remarkable that we can now provide long-term records for hundreds of glaciers, finally enabling us to document the response of Greenland’s glaciers to climate change over more than a century.
The multi-year study concluded that the rate of glacier retreat has doubled since 2000, and that rising air and ocean temperatures due to human-induced climate change are responsible for this negative record. “Our activities over the next few decades will significantly affect these glaciers. Any increase in temperature really matters,” said Laura Larocca, first author of the study.