Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Breakup of glaciers raising sea level concern

21.10.2005


The rapid structural breakdown of some important parts of the ice sheets on Greenland and Antarctica is possible, has happened in the distant past, and some "startling changes" on the margin of these ice masses has been observed in recent years – raising disturbing concerns about sea level rise.



In a new report to be released Friday in the journal Science, researchers from Oregon State University and four other institutions in the U.S. and Europe outline dynamic mechanisms of glacial change that appear to be under way, could significantly speed up the melting of major ice sheets, and have not been considered in current projections for sea level rise.

A possibility, scientists say, is that the melting and collapse of floating ice shelves near the coasts of Greenland and Antarctica will continue and in the process destabilize the ice sheets behind them. This could cause a much more rapid flow of ice to the sea and lead to melting events that transcend those now anticipated due to global warming. Based on this, the researchers say that current projections of sea level rise should be considered a minimum to expect, and the levels could be much higher and happen more quickly.


"Most of the sea level rise we’re now expecting in the next 200 years is due to thermal expansion of water, not the overall loss of ice from Greenland and Antarctica," said Peter Clark, a professor of geosciences at OSU. "But recent events we’ve studied with improved observational systems and computer modeling suggest there may be much more going on."

"We may be more vulnerable to sea level rise than we thought and it may be more rapid than we have anticipated," Clark said. "This is an issue we should take very seriously."

Although they are learning a great deal more about the mechanisms that may lead to more rapid glacial collapse, the scientists cannot yet predict with certainty whether or how fast it might happen, or what the resulting sea level rise may be.

In one event about 14,600 years ago, Earth’s sea level rose about 70 feet in less than 500 years – 20 times faster than the current rate of sea level rise. However, climatic conditions then may have been considerably different than today, and that event may not provide an exact analog to what we might expect from current glacial melting events, Clark said. Nevertheless, that event illustrates the potential for existing ice sheets to cause sea level to rise rapidly, he said.

Current projections in climate models suggest that global warming will cause some melting of glacial ice in Greenland in the next century or two, but that may be largely offset by increased precipitation and glacial buildup in Antarctica. During that period, thermal warming of the Earth’s oceans is expected to increase sea level by about one-half meter, Clark said. The breakdown of glaciers currently being studied could double the sea level rise to a full meter, he said.

Even more problems are anticipated later on. The Greenland ice sheet may disappear within about 1,000 years, raising Earth’s sea level by about 20 feet, and the glacial breakdown mechanisms being studied could speed that up considerably.

What has caught the attention of scientists in recent years is the rapid collapse of some glaciers near the coasts of Greenland and Antarctica.

Jakobshavn glacier in Greenland nearly doubled its flow speed in the past decade. Along the Antarctic Peninsula, warming over the past few decades has caused retreat or near-total loss of several ice shelves, some of which had existed for thousands of years - and surface melting cannot explain most of the losses. In 2002 the Larsen B Ice Shelf in Antarctica collapsed, and major tributary glaciers entering the former ice shelf began to move 2-8 times faster than they had previously. Also in Antarctica, large glaciers feeding the Amundsen Coast thinned and accelerated by up to 26 percent over the last three decades, with repercussions more than 120 miles inland.

It’s become clear, Clark said, that the West Antarctic Ice Sheet, much of which sits on land that’s actually below sea level, is one of the most vulnerable in the world to these types of rapid breakdowns. If it were to melt, that would add another 20 feet to global sea levels.

In future modeling of potential sea level rise, the researchers said in their report, it’s essential that the mechanisms for breakup of major ice sheets in Greenland and Antarctica be more carefully considered in the projections. If these mechanisms continue and prove to be significant, sea level projections will have to be revised upward, the scientists said.

Other collaborators on this study were from Pennsylvania State University, the University of Washington, and institutes or universities in Germany and Belgium.

"The events that have happened so far are pretty small, compared to what we’re concerned about," Clark said. "The real problem would occur if these smaller glacial breakups trigger larger ones, and rising sea levels by themselves might cause a feedback mechanism which would further speed up the process."

Peter Clark | EurekAlert!
Further information:
http://www.geo.orst.edu

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: It’s All in the Mix: Jülich Researchers are Developing Fast-Charging Solid-State Batteries

There are currently great hopes for solid-state batteries. They contain no liquid parts that could leak or catch fire. For this reason, they do not require cooling and are considered to be much safer, more reliable, and longer lasting than traditional lithium-ion batteries. Jülich scientists have now introduced a new concept that allows currents up to ten times greater during charging and discharging than previously described in the literature. The improvement was achieved by a “clever” choice of materials with a focus on consistently good compatibility. All components were made from phosphate compounds, which are well matched both chemically and mechanically.

The low current is considered one of the biggest hurdles in the development of solid-state batteries. It is the reason why the batteries take a relatively long...

Im Focus: Color effects from transparent 3D-printed nanostructures

New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference

Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...

Im Focus: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

LaserForum 2018 deals with 3D production of components

17.08.2018 | Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

 
Latest News

A novel synthetic antibody enables conditional “protein knockdown” in vertebrates

20.08.2018 | Life Sciences

Metamolds: Molding a mold

20.08.2018 | Information Technology

It’s All in the Mix: Jülich Researchers are Developing Fast-Charging Solid-State Batteries

20.08.2018 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>