Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Past Antarctic ice sheet development linked to ocean temperatures and carbon dioxide

17.09.2004


New research published in the September 17 issue of the journal Science sheds light on the evolution of Earth’s climate system by identifying changes in temperature, ocean circulation, and global carbon cycling associated with the rapid growth of Antarctic ice sheets approximately 14 million years ago.


View of East Antarctic Ice Sheet from Australia’s Mawson Station. Photo credit Katharine Burgdorff


Iceberg, Davis Sea, East Antarctica. Photo credit Robert Dunbar



By studying chemical changes in deep sea sediments, scientists at the University of California, Santa Barbara discovered that high-latitude Southern Ocean cooling helped to trigger this major expansion of Antarctic ice sheets, which have since become a permanent feature of the global climate system. These results document ice sheet history and supply crucial insight into the dynamics of the global climate system.

Scientists have long recognized that the Southern Ocean and the development of Antarctic ice sheets play a major role in the evolution of Earth’s present climate system. Only now have researchers been able to obtain a clearer picture of the relationship between high-latitude temperatures, global carbon cycling and the size of Antarctic ice sheets.


Southern Ocean temperature data exhibits a rapid 7 degree cooling of surface waters around 14 million years ago and suggests a strengthening of the Antarctic Circumpolar Current in response to changes in the geometry of Earth’s orbits. As a result, Antarctica became increasingly isolated from tropical heat and moisture sources. Records of Antarctic ice volume indicate that following this cooling ice sheets expanded rapidly to near present-day size, which suggests that changes in the Southern Ocean directly influence the size of the Antarctic ice sheet.

UCSB researchers speculate that the climate system responded quickly to orbital variations because of generally low atmospheric carbon dioxide levels and plate tectonic changes north and south of Australia. "Our study indicates that the sensitivity of Earth’s climate system can shift rapidly when climate boundary conditions, such as atmospheric greenhouse gas levels or the configuration of the continents, change," said Amelia Shevenell, the lead author of the Science study and a Ph.D. candidate at UCSB. "Our results suggest that scientifically it is somewhat incidental whether these boundary conditions are altered via natural or human-induced processes," she said. "If the boundary conditions change, we should expect Earth’s climate system to respond."

Shevenell and co-authors Jim Kennett and David Lea, both professors of Geological Sciences at UCSB, developed the records of Southern Ocean sea surface temperature change, Antarctic ice volume, and global carbon cycling by measuring chemical changes in the fossilized skeletal remains of marine plankton contained in deep-sea sediments. Shevenell and Kennett collected these sediments south of Tasmania when they sailed as scientists on the Ocean Drilling Program’s drill ship, the JOIDES Resolution.

Gail Gallessich | EurekAlert!
Further information:
http://www.ucsb.edu

More articles from Earth Sciences:

nachricht NASA examines Peru's deadly rainfall
24.03.2017 | NASA/Goddard Space Flight Center

nachricht Steep rise of the Bernese Alps
24.03.2017 | Universität Bern

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>