Science & Technology

Vulnerable to Climate Change: Huge Antarctic Glacier Melting From the Bottom Up

This {photograph} exhibits ripples in the floor of Denman Glacier in East Antarctica that throw shadows towards the ice. The glacier is melting at a quicker charge now than it was from 2003 to 2008. Credit score: NASA

The form of the floor beneath Denman Glacier, which is melting from the backside up, makes it notably weak to the intrusion of seawater.

Denman Glacier in East Antarctica retreated 3.4 miles (5.4 kilometers) from 1996 to 2018, in accordance to a brand new examine by scientists at NASA’s Jet Propulsion Laboratory and the College of California, Irvine. Their evaluation of Denman — a single glacier that holds as a lot ice as half of West Antarctica — additionally exhibits that the form of the floor beneath the ice sheet makes it particularly prone to climate-driven retreat.

Till just lately, researchers believed East Antarctica was extra secure than West Antarctica as a result of it wasn’t dropping as a lot ice in contrast to the glacial soften noticed in the western a part of the continent. “East Antarctica has lengthy been thought to be much less threatened, however as glaciers similar to Denman have come beneath nearer scrutiny by the cryosphere science neighborhood, we are actually starting to see proof of potential marine ice sheet instability on this area,” stated Eric Rignot, challenge senior scientist at JPL and professor of Earth system science at UCI.

“The ice in West Antarctica has been melting quicker lately, however the sheer dimension of Denman Glacier implies that its potential impression on long-term sea stage rise is simply as vital,” Rignot added. If all of Denman melted, it will end in about 4.9 ft (1.5 meters) of sea stage rise worldwide.

This illustration exhibits a vertically exaggerated picture of the floor beneath Denman Glacier in East Antarctica, together with a deep trough (blue space in the middle) beneath its jap flank. Credit score: NASA’s Scientific Visualization Studio

Utilizing radar information from 4 satellites, a part of the Italian COSMO-SkyMed mission that launched its first satellite tv for pc in 2007, the researchers have been ready to discern the exact location the place the glacier meets the sea and the ice begins to float on the ocean, or its grounding zone. The scientists have been additionally ready to reveal the contours of the floor beneath parts of the glacier utilizing information on ice thickness and its velocity over land.

Denman’s jap flank is protected against publicity to heat ocean water by a roughly 6-mile-wide (10-kilometer-wide) ridge beneath the ice sheet. However its western flank, which extends about 3 miles (4 kilometers) previous its jap half, sits over a deep, steep trough with a backside that’s clean and slopes inland. This configuration might funnel heat seawater beneath the ice, making for an unstable ice sheet. The nice and cozy water is more and more being pushed towards the Antarctic continent by winds known as the westerlies, which have strengthened since the Nineteen Eighties.

“Due to the form of the floor beneath Denman’s western aspect, there may be potential for the intrusion of heat water, which might trigger speedy and irreversible retreat, and contribute to world sea stage rise in the future,” stated lead creator Virginia Brancato, a scientist at JPL.

It’ll even be essential, her colleague Rignot famous, to monitor the a part of Denman Glacier that floats on the ocean, which extends for 9,300 sq. miles (24,000 sq. kilometers) and consists of the Shackleton Ice Shelf and Denman Ice Tongue.

At the moment, that extension is melting from the backside up at a charge of about 10 ft (3 meters) yearly. That’s a rise over its annual soften common of 9 ft (2.7 meters). It’s additionally higher than the common soften charge for East Antarctic ice cabinets between 2003 and 2008, which was roughly 2 ft (0.7 meters) per yr.

The crew revealed their evaluation on March 23 in the American Geophysical Union journal Geophysical Analysis Letters.

Learn for extra on this analysis.

Reference: “Grounding line retreat of Denman Glacier, East Antarctica, measured with COSMO‐SkyMed radar interferometry information” by V. Brancato, E. Rignot, P. Milillo, M. Morlighem, J. Mouginot, L. An, B. Scheuchl, S. Jeong, P. Rizzoli, J.L. Bueso Bello and P. Prats‐Iraolaal, 23 March 2020, Geophysical Analysis Letters.

This challenge was funded by NASA’s Cryosphere Program and acquired assist from the Italian House Company and the German House Company. Knowledge and mattress topography maps are .



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