Alaska's Columbia Glacier has retreated significantly by more than 20 kilometers since the 1980s, with climate change being a major factor. Satellite images from 2023 highlight dramatic changes in the glacier and the advanced technology used to monitor these changes.The Copernicus Sentinel-2 mission takes us over Alaska's Columbia Glacier, one of the fastest-changing glaciers in the world.
This satellite image from the Copernicus Sentinel-2 mission shows the rapid retreat of Alaska's Columbia Glacier. Since the 1980s, the Columbia Glacier has retreated more than 20 kilometers, losing about half its volume. Image source: Contains modified Copernicus Sentinel data (2023), processed by ESA, CCBY-SA3.0IGO
The Columbia Glacier, just above center of the image, is a tidewater glacier that flows down the snow-covered slopes of the Chugach Mountains, which dominate the upper half of the image. The range contains the largest concentration of glaciers in Alaska.
Since the early 1980s, the Columbia Glacier has retreated more than 20 kilometers, losing about half of its total volume. This single glacier accounts for almost half of the ice loss from the Chugach Mountains.
Climate change is thought to be the cause of glacier retreat. Until 1980, when the glacier began its rapid and sustained retreat, the glacier's terminus was observed on the northern edge of Heather Island, near the end of Columbia Bay, where the glacier currently flows through the inlet before emptying into Prince William Sound. This satellite image was taken in September 2023. It shows that the depths of Columbia Bay are basically ice-free, dotted with numerous icebergs and broken sea ice.
Depending on the amount of sediment coming from the Chugach Mountains, the water appears different colors throughout the image: the clear water in the Pacific Ocean appears dark blue, while the turbid water in estuaries and glacial lakes appears light blue or cyan.
Columbia is just one of many glaciers affected by climate change. The quality of most glaciers around the world is declining. Before satellites, however, measuring glacier retreat and studying the extent to which glaciers were vulnerable to climate change was difficult given their size, remoteness and rugged terrain.
Different satellite instruments can now systematically collect information over large areas, providing an effective means of monitoring changes, tracking all calving stages, and quantifying melt rates and their impact on sea level rise.
Compiled source: ScitechDaily