Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

NASA Eyes Ice Changes Around Earth’s Frozen Caps

15.12.2004


At 32 degrees Fahrenheit, or 0 Celsius, ice changes to water. This simple, unique fact dominates the climate in Earth’s polar regions. Using satellites to detect changes over time, NASA researchers and NASA-funded university scientists have found that Earth’s ice cover is changing rapidly near its poles. Recent studies point to new evidence of relationships between climate warming, ice changes and sea level rise.



Two researchers from NASA Goddard Space Flight Center (GSFC), Greenbelt, Md., and a glaciologist from the University of Colorado’s National Snow and Ice Data Center, Boulder, Colo., will discuss new findings related to Earth’s ice cover at a press conference on Dec. 14 at the 2004 meeting of the American Geophysical Union in San Francisco, Calif.

Waleed Abdalati, a NASA GSFC researcher, has worked with colleagues on a slew of recent papers on glaciers and ice sheets in the Northern Hemisphere. Bill Krabill of NASA Wallops Space Flight Center, Wallops Island, Va., Abdalati and others calculated that Greenland’s contributions to sea level rise nearly doubled in recent years, from 0.13 millimeters (mm) (.005 inches) per year in the mid 1990s, to 0.25 mm (.01 inches) per year from 1997 to 2003. Krabill’s study measured steady thinning in the region’s lower elevations near the coasts.


A recent NASA paper in Nature found that the world’s fastest glacier, called the Jakobshavn Isbrae, nearly doubled its speed from 1997 to 2003. The speedy ice stream’s quickening coincided with a break up of the floating ice that extends from the glacier out into the ocean, called an ice tongue. In 2003, this one glacier added to the world’s oceans an amount of water equal to about 4 percent of the estimated rate of sea level rise.

Abdalati also published a paper in the Journal of Geophysical Research assessing the contributions of the Canadian ice caps to sea level rise. During the late 1990s they contributed an estimated 0.065 mm (0.002 inches) per year, which, while not as large as those of Greenland and neighboring Alaska, is still quite significant. Perhaps more significant is the fact that like Greenland and Alaska the rate of ice loss appears to have accelerated in recent years.

Meanwhile, the Arctic Ocean’s perennial sea ice, or the sea ice that lasts all year long, continues to decline. Floating sea ice blankets the ocean surface, and does not contribute to sea level rise. But it is an important part of the climate system because the expansive white ice reflects the sun’s heating rays, prevents the oceans beneath it from absorbing more heat, influences ocean circulation, and regulates Earth’s climate. Between 2002 and 2004, Arctic sea ice has been exceptionally low. 2002 set a record for the lowest amount of late summer sea ice since satellite measurements of the area began in 1978. Josefino Comiso of NASA’s GSFC reported that between 1978 and 2000, the Arctic perennial sea ice declined by 8.9 percent per decade. The trend is now 9.2 percent per decade. These low levels continue to be sustained in 2003 and 2004.

While a few abnormally cold summers would help sea ice survive the summer melt, Comiso’s studies have found that on average, during the past 22 years, the Arctic warming rate is about 8 times higher than estimates of warming rates over the last 100 years.

In much of the Antarctic, a general cooling has been observed and sea ice has mostly increased over the last 30 years but the Antarctic Peninsula has been an exception since it has warmed and similar rapid changes as those found in the northern hemisphere have been observed.

For example, in the eastern Antarctic Peninsula, very rapid climate warming began in the 1950s, causing mean temperatures to increase by about 2.5 degrees Celsius (4.5 Fahrenheit), according to Scambos. As temperatures have warmed, land and sea ice have melted. In March 2002, the Rhode-Island-sized Larsen B ice shelf collapsed, the largest in a series of such retreats that began to take place around 1985 and have steadily increased.

In the aftermath of this collapse, two NASA studies, one led by Scambos, showed that glaciers flowing into the bay areas behind the Larsen ’B’ ice shelf accelerated by 3- to 8-fold in just 18 months after the breakup. This finding points to similar mechanisms as those discovered by Abdalati and colleagues in Greenland’s Jakobshavn ice stream. Satellite images revealed that the Antarctic glaciers’ speed-up began almost immediately after the collapse of the shelf. Data from NASA’s new ICESat satellite indicate that the trunk of one glacier decreased in elevation by over 30 meters in just six months.

Krishna Ramanujan | EurekAlert!
Further information:
http://www.nasa.gov/vision/earth/lookingatearth/icecover.html
http://www.nasa.gov

More articles from Earth Sciences:

nachricht New research calculates capacity of North American forests to sequester carbon
16.07.2018 | University of California - Santa Cruz

nachricht Scientists discover Earth's youngest banded iron formation in western China
12.07.2018 | University of Alberta

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Subaru Telescope helps pinpoint origin of ultra-high energy neutrino

16.07.2018 | Physics and Astronomy

Barium ruthenate: A high-yield, easy-to-handle perovskite catalyst for the oxidation of sulfides

16.07.2018 | Life Sciences

New research calculates capacity of North American forests to sequester carbon

16.07.2018 | Earth Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>