Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Climate Models Overheat Antarctica

08.05.2008
Computer analyses of global climate have consistently overstated warming in Antarctica, concludes a new study. The findings can help scientists improve computer models and determine if the southernmost continent will warm significantly this century, a major research question because of Antarctica's potential impact on global sea-level rise.

"We can now compare computer simulations with observations of actual climate trends in Antarctica," says Andrew Monaghan of the National Center for Atmospheric Research (NCAR) in Boulder, Colo., lead author of the study.

"This is showing us that, over the past century, most of Antarctica has not undergone the fairly dramatic warming that has affected the rest of the globe. The challenges of studying climate in this remote environment make it difficult to say what the future holds for Antarctica's climate."

The study marks the first time that scientists have been able to compare the past 50 to 100 years of Antarctic climate with simulations run on computer models.

The models are a primary method for researchers to project future climate.
Scientists have used atmospheric observations to confirm that computer models are accurately simulating climate for the other six continents.

Antarctica's climate is of worldwide interest, in part because of the enormous water locked up in its ice sheets. If those vast ice sheets were to begin to melt, sea level could rise across the globe and inundate low-lying coastal areas. Yet, whereas climate models accurately simulate the last century of warming for the rest of the world, they have unique challenges simulating Antarctic climate because of limited information about the continent's harsh weather patterns.

Monaghan and his colleagues at NCAR and Ohio State University, in Columbus, published their findings last month in Geophysical Research Letters, a journal of the American Geophysical Union (AGU).

The authors compared recently constructed temperature data sets from Antarctica, based on data from ice cores and ground weather stations, to twentieth century simulations from computer models used by scientists to simulate global climate.

While the observed Antarctic temperatures rose by about 0.2 degrees Celsius (0.4 degrees Fahrenheit) over the past century, the climate models simulated increases in Antarctic temperatures during the same period of 0.75 degrees C (1.4 degrees F). The error appeared to be caused by models overestimating the amount of water vapor in the Antarctic atmosphere, the new study concludes.

The models, however, have correctly captured trends in Antarctic snowfall, including increases in snowfall in the late twentieth century, prior to a decrease over the last decade.

Part of the reason that Antarctica has barely warmed has to do with the ozone hole over the continent. The lack of ozone is chilling the middle and upper atmosphere, altering wind patterns in a way that keeps comparatively warm air from reaching the surface. Unlike the rest of the continent, the Antarctic Peninsula has warmed by several degrees, in part because the winds there are drawing in warmer air from the north.

The study delivered a mixed verdict on Antarctica's potential impact on sea-level rise. The Intergovernmental Panel on Climate Change, which operates under the auspices of the United Nations, has estimated that sea-level rise could amount to 18 to 59 centimeters (7 to 23 inches) this century, in part because of melting glaciers worldwide. The new findings suggest that other effects of warming in Antarctica over the next century could reduce that by about 5 centimeter (2 inches) if the continent warms by 3 degrees C (5.4 degrees F) as computer models have indicated. The reason is that the warmer air over Antarctica would hold more moisture and generate more snowfall, thereby locking up additional water in the continent's ice sheets.

But the authors caution that model projections of future Antarctic climate may be unreliable.

"The research clearly shows that you can actually slow down sea-level rise when you increase temperatures over Antarctica because snowfall increases, but warmer temperatures also have the potential to speed up sea-level rise due to enhanced melting along the edges of Antarctica," says Monaghan, who did some of his research at Ohio State University before going to NCAR. "Over the next century, whether the ice sheet grows from increased snowfall or shrinks due to more melt will depend on how much temperatures increase in Antarctica, and potentially on erosion at the ice sheet edge by the warmer ocean and rising sea level."

"The current generation of climate models has improved over previous generations, but still leaves Antarctic surface temperature projections for the twenty- first century with a high degree of uncertainty," adds co-author and NCAR scientist David Schneider. "On a positive note, this study points out that water vapor appears to be the key cause of the problematic Antarctic temperature trends in the models, which will guide scientists as they work to improve the climate simulations."

This study was funded by National Science Foundation and by the Department of Energy.

Peter Weiss | American Geophysical Union
Further information:
http://www.agu.org
http://dx.doi.org/10.1029/2007GL032630
http://www.ucar.edu/news/releases/2008/antarctica.jsp

More articles from Earth Sciences:

nachricht NASA examines newly formed Tropical Depression 3W in 3-D
26.04.2017 | NASA/Goddard Space Flight Center

nachricht Early organic carbon got deep burial in mantle
25.04.2017 | Rice University

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

Scientist invents way to trigger artificial photosynthesis to clean air

26.04.2017 | Materials Sciences

Ammonium nitrogen input increases the synthesis of anticarcinogenic compounds in broccoli

26.04.2017 | Agricultural and Forestry Science

SwRI-led team discovers lull in Mars' giant impact history

26.04.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>