From the American Geophysical Union, a press release about a paper not yet published: Glaciers that detach from the seafloor and begin floating create larger icebergs than glaciers that stay on the sea floor, researchers have found. Floating glaciers also produce icebergs more erratically. These new observations may help researchers better understand and predict iceberg production from glaciers and ice sheets, improving estimates of sea-level rise due to climate change.“If we want to have accurate predictions of sea-level rise, we need to understand how to model iceberg calving,” says Fabian Walter, a glaciologist at the Scripps Institution of Oceanography, in La Jolla, Calif. Walter is lead author of the study, which has been accepted for publication in Geophysical Research Letters, a journal of the American Geophysical Union (AGU). “Calving” is the term for icebergs breaking off from glaciers.
This study presents the first detailed observation of a glacier undergoing a transition from grounded (resting on the ocean floor) to floating, as is currently happening to a section of Columbia Glacier, one of Alaska's many tidewater glaciers. Tidewater glaciers flow directly into the ocean, ending at a cliff in the sea, where icebergs are formed. Prior to this study, Alaskan tidewater glaciers were believed to be exclusively grounded and unable to float without disintegrating.
Icebergs are a leading source of water for the global ocean basin. Despite this, iceberg calving is one of the least understood processes involved in ice mass loss and the corresponding sea-level rise. This study is part of a larger effort to understand the formation of icebergs from glaciers and to include that process in large-scale glacier models….
Columbia Glacier, in the Chugach National Forest, Chugach Mountains, Prince William Sound. Photo by the US Fish and Wildlife Service
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