Summit County Citizens Voice

New research helps pinpoint future ice loss and sea-level rise

Collapsing ice shelves lead to long-term loss of glacial ice. PHOTO BY BOB BERWYN.

By Summit Voice

SUMMIT COUNTY — A new studies from Antarctica shows how collapsing ice shelves speed up ice loss on adjacent glaciers. The data will lead to more accurate predictions about ice loss and sea level rise resulting from ongoing changes along the Antarctic Peninsula.

“Not only do you get an initial loss of glacial ice when adjacent ice shelves collapse, but you get continued ice losses for many years, even decades, to come,” said researcher Christopher Shuman. “This further demonstrates how important ice shelves are to Antarctic glaciers.”

The research team included Ted Scambos, from the Boulder-based National Snow and Ice Data Center at the University of Colorado.

“This study shows where the tracking of sea level rise is heading in terms of the level of detail possible and the instrumentation that can be brought to bear,” Scambos said. “We’re showing that glacier changes can start fast, with a single climate or ocean ‘bang’, but they have a long persistence.”

An ice shelf is a thick floating tongue of ice, fed by a tributary glacier, extending into the sea off a land mass. Previous research showed that the recent collapse of several ice shelves in Antarctica led to acceleration of the glaciers that feed into them.

The team used satellite data and other measurements to produce detailed ice loss maps from 2001 to 2009 for the main tributary glaciers of the Larsen A and B ice shelves, which collapsed in 1995 and 2002, respectively.

The analysis reveals rapid elevation decreases of more than 500 feet for some glaciers, and it puts the total ice loss from 2001 to 2006 squarely between the widely varying and less certain estimates produced using an approach that relies on assumptions about a glacier’s mass budget. The authors’ analysis shows ice loss in the study area of at least 11.2 gigatons per year from 2001 to 2006. Their ongoing work shows ice loss from 2006 to 2010 was almost as large, averaging 10.2 gigatons per year.

“The approach we took drew on the strengths of each data source to produce the most complete picture yet of how these glaciers are changing,” Berthier said, noting that the study relied on easy access to remote sensing information provided by NASA and CNES. The team used data from NASA sources including the Moderate Imaging Spectroradiometer (MODIS) instruments and the Ice, Cloud, and land Elevation Satellite (ICESat).

The international group included scientists from the Boulder-based National Snow and Ice Data Center (University of Colorado), the University of Maryland, Baltimore County and the Laboratoire d’Etudes en Géophysique et Océanographie Spatiales, Centre National de la Recherche Scientifique at the University of Toulouse, France.

Filed under: climate and weather, Environment, global warming, Summit County news Tagged: | Antarctic Peninsula, climate change, Glacier, global warming, Ice shelf, ICESat, Larsen Ice Shelf, National Snow and Ice Data Center, sea level rise