Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Whether glaciers float may affect sea-level rise

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.

“We’re seeing more tidewater glaciers retreat,” says Walter. “As they retreat, they thin, and that increases the likelihood that they’ll come afloat.”

The research team conducted their study on Columbia Glacier by installing a seismometer−a sensor that measures seismic waves that are produced by shifts in geologic formations, including earthquakes, landslides, and the calving of icebergs. The scientists studied the seismometer readings from 2004-2005 and 2008-2009, which allowed them to compare size and frequency of icebergs calved by a glacier before and after it became floating.

Calving occurs when fractures in the ice join up and cause a piece of ice to completely separate from the main glacier to form an iceberg. Unlike the floating glaciers, grounded glaciers calve icebergs nearly continuously, which means they generally form smaller icebergs.

The speed at which the Columbia Glacier is receding may also have contributed to a section of its ice coming afloat, says glaciologist Shad O’Neel of the U.S. Geological Survey (USGS), in Anchorage, Alaska, who coauthored the paper. Columbia is one of the fastest-receding glaciers in the world, having retreated 4 kilometers (2.49 miles) since 2004, and nearly 20 km (12.43 mi) since 1980.

This research was funded by a grant from the National Science Foundation.

Scripps Institution of Oceanography is a graduate school of the University of California at San Diego.

Notes for Journalists
As of the date of this press release, the paper by Walter et al. is still “in press” (i.e. not yet published). Journalists and public information officers (PIOs) of educational and scientific institutions who have registered with AGU can download a PDF copy of this paper in press at
Or, you may order a copy of the paper by emailing your request to Kathleen O’Neil at Please provide your name, the name of your publication, and your phone number.

Neither the paper nor this press release are under embargo.

Iceberg calving during transition from grounded to floating ice: Columbia Glacier, Alaska
Fabian Walter, Helen Amanda Fricker: Institute of Geophysics and Planetary Physics, University of California, San Diego, La Jolla, California, USA;

Shad O’Neel: United States Geological Survey, Alaska Science Center, Anchorage, Alaska, USA;

Daniel McNamara: United States Geological Survey, Golden, Colorado, USA;

Tad Pfeffer: Institute of Arctic and Alpine Research, University of Colorado, Boulder, Colorado, USA USA;

Jeremy Bassis: Geological Sciences, University of Michigan, Ann Arbor, Michigan, USA.

Contact information for the authors:
Fabian Walter, UCSD – Dr. Walter is in the field in Switzerland, but can be reached by cell phone: +41 79 657 8087 Shad O’Neel, USGS: 907-786-7088,

Kathleen O’Neil | American Geophysical Union
Further information:

More articles from Earth Sciences:

nachricht UCI and NASA document accelerated glacier melting in West Antarctica
26.10.2016 | University of California - Irvine

nachricht Ice shelf vibrations cause unusual waves in Antarctic atmosphere
25.10.2016 | American Geophysical Union

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Greater Range and Longer Lifetime

26.10.2016 | Power and Electrical Engineering

VDI presents International Bionic Award of the Schauenburg Foundation

26.10.2016 | Awards Funding

3-D-printed magnets

26.10.2016 | Power and Electrical Engineering

More VideoLinks >>>