When studying the impact of climate change on Greenland’s ice, scientists have primarily focused on the vast ice sheet that covers most of the island. However, little attention has been given to the thousands of peripheral glaciers that exist along Greenland’s coast—until now.

Using a combination of historical aerial photographs and satellite imagery, researchers have examined over 1,000 peripheral glaciers from 1890 to 2022. Unfortunately, the findings are disturbing. The rate of retreat for these glaciers has doubled in the past 20 years.

While peripheral glaciers only make up approximately 4 percent of Greenland’s ice-covered area, they contribute to 14 percent of the island’s current ice loss. This disproportionate impact highlights their significance in the overall problem of rising sea levels. As a matter of fact, if we consider all global glaciers separate from the Greenland and Antarctic Ice Sheet, they have contributed about 21 percent to observed sea level rise in the last two decades.

The discovery and analysis of historical aerial photographs played a crucial role in this study. Prior to the launch of Earth-observing satellites in the 1970s, it was believed that detailed observational records of Greenland’s peripheral glaciers did not exist. However, around 15 years ago, an archive of old photographs was discovered, which included images of Greenland’s coastline taken by pilots in open-cockpit airplanes.

These photographs have expanded the dataset, providing valuable information about glacier responses to climate change over a century. This new insight is vital, considering the rarity of widespread cryosphere observations in the pre-satellite era.

The increased retreat of Greenland’s peripheral glaciers is a concerning trend. Further research and monitoring of these glaciers will be crucial in understanding and mitigating the impact of climate change on the world’s ice masses and sea levels.