Nav: Home

Tidewater glaciers: Melting underwater far faster than previously estimated?

July 25, 2019

A tidewater glacier in Alaska is melting underwater at rates upwards of two orders of magnitude greater than what is currently estimated, sonar surveys reveal. The study's results, based on direct measurements, suggest that some glaciers may be in "hotter water" than previously thought. Like vast frozen rivers, tidewater glaciers flow from the land and into the sea, forming a partially submerged ice-ocean boundary. However, unlike terrestrial glaciers, which are often sequestered to high-altitudes, tidewater glaciers can be far more dynamic and subject to ongoing changes driven by underwater melting and iceberg calving where the ocean meets the ice. While it is widely recognized that ice loss from these glaciers influences both the rate of sea level rise and potentially global ocean circulation - a primary driver of global climate - the understanding of the dynamics of tidewater glacier melt, particularly as a response to accelerated warming in high-latitude glacier environments, is largely predicated upon sparse data, indirect inferences and an unconstrained theoretical model of subsurface melting. To date, suggest the authors of this study, no direct measurements of submarine melting at tidewater glacier fronts have been made. To address this lack of direct observations, David Sutherland and colleagues conducted repeat multibeam sonar surveys of the submerged face of the LeConte Glacier in Southeast Alaska. Along with other ocean, ice and atmospheric measurements collected in August 2016 and May 2017, the sonar images were used to document and create a time-variable, three-dimensional record of changes in the glacier face that could be linked to melting and calving patterns. Sutherland et al. discovered seasonally increasing submarine melt across the glacier face and at rates far greater than theory-based predictions. Their results, they say, suggest a pressing need to reevaluate existing models of tidewater glacier ice loss.
-end-


American Association for the Advancement of Science

Related Glaciers Articles:

Saying goodbye to glaciers
Glaciers around the world are disappearing before our eyes, and the implications for people are wide-ranging and troubling, Twila Moon, a glacier expert at the University of Colorado Boulder, concludes in a Perspectives piece in the journal Science today.
Glaciers rapidly shrinking and disappearing: 50 years of glacier change in Montana
The warming climate has dramatically reduced the size of 39 glaciers in Montana since 1966, some by as much as 85 percent, according to data released by the U.S.
Polar glaciers may be home to previously undiscovered carbon cycle
Microbes in streams flowing on the surface of glaciers in the Arctic and Antarctic may represent a previously underestimated source of organic material and be part of an as yet undiscovered 'dynamic local carbon cycle,' according to a new paper published by researchers supported by the National Science Foundation.
Study shows planet's atmospheric oxygen rose through glaciers
A 'Snowball Earth' event actually took place 100 million years earlier than previously projected.
Researchers find seafloor valleys below West Antarctic glaciers
Glaciologists have uncovered large valleys in the ocean floor beneath some of the massive glaciers flowing into the Amundsen Sea in West Antarctica.
Mountain glaciers are showing some of the strongest responses to climate change
Tying an individual glacier's retreat to climate change has been controversial.
Most meltwater in Greenland fjords likely comes from icebergs, not glaciers
Icebergs contribute more meltwater to Greenland's fjords than previously thought, losing up to half of their volume as they move through the narrow inlets, according to new research.
Receding glaciers in Bolivia leave communities at risk
A new study published in The Cryosphere, an European Geosciences Union journal, has found that Bolivian glaciers shrunk by 43 percent between 1986 and 2014, and will continue to diminish if temperatures in the region continue to increase.
Technique could assess historic changes to Antarctic sea ice and glaciers
Historic changes to Antarctic sea ice could be unravelled using a new technique pioneered by scientists at Plymouth University.
Cosmopolitan snow algae accelerate the melting of Arctic glaciers
The role of red pigmented snow algae in melting Arctic glaciers has been strongly underestimated, suggests a study to be published in Nature Communications on June 22.

Related Glaciers Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Anthropomorphic
Do animals grieve? Do they have language or consciousness? For a long time, scientists resisted the urge to look for human qualities in animals. This hour, TED speakers explore how that is changing. Guests include biological anthropologist Barbara King, dolphin researcher Denise Herzing, primatologist Frans de Waal, and ecologist Carl Safina.
Now Playing: Science for the People

#SB2 2019 Science Birthday Minisode: Mary Golda Ross
Our second annual Science Birthday is here, and this year we celebrate the wonderful Mary Golda Ross, born 9 August 1908. She died in 2008 at age 99, but left a lasting mark on the science of rocketry and space exploration as an early woman in engineering, and one of the first Native Americans in engineering. Join Rachelle and Bethany for this very special birthday minisode celebrating Mary and her achievements. Thanks to our Patreons who make this show possible! Read more about Mary G. Ross: Interview with Mary Ross on Lash Publications International, by Laurel Sheppard Meet Mary Golda...