Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Past climate of the northern Antarctic Peninsular informs global warming debate

10.11.2009
Past Antarctic climate

The seriousness of current global warming is underlined by a reconstruction of climate at Maxwell Bay in the South Shetland Islands of the Antarctic Peninsula over approximately the last 14,000 years, which appears to show that the current warming and widespread loss of glacial ice are unprecedented.

"At no time during the last 14 thousand years was there a period of climate warming and loss of ice as large and regionally synchronous as that we are now witnessing in the Antarctic Peninsula," says team member Dr Steve Bohaty of the National Oceanography Centre, Southampton (NOCS), home of the University of Southampton's School of Ocean and Earth Science (SOES)."

The findings are based on a detailed analysis of the thickest Holocene sediment core yet drilled in the Antarctic Peninsula. "By studying the climate history of the past and identifying causes of these changes, we are better placed to evaluate current climate change and its impacts in the Antarctic," says Dr Bohaty.

As part of a 2005 research cruise aboard the American icebreaker RV/IB Nathanial B. Palmer, the scientists drilled down through the sediments at Maxwell Bay, a fjord at the northwest tip of the Antarctic Peninsula. They drilled down as far as the bedrock, obtaining a nearly complete 108.3-metre sediment core.

Back in the lab, they performed a battery of detailed sedimentological and geochemical analyses on the core. Radiocarbon dating showed that the oldest sediments at the bottom of the core were deposited between 14.1 and 14.8 thousand years ago, and sedimentation rates at the site varied from 0.7 to around 30 milimetres a year through the Holocene; that is, the geological period that began around 11,700 years ago, continuing to the present.

They conclude that ice was grounded in the fjord during the Last Glacial Maximum – the height of the last ice age – and eroded older sediments from the fjord. Later, the grounded ice retreated, leaving a permanent floating ice canopy.

The evidence points to a period of rapid glacial retreat from 10.1 to 8.2 thousand years ago, followed by a period of reduced sea-ice cover and warm water conditions occurring between 8.2 and 5.9 thousand years ago. An important finding of the study is that the mid-Holocene warming interval does not appear to have occurred synchronously throughout the region, and its timing and duration was most likely influenced at different sites by local oceanographic controls, as well as physical geography.

Following the mid-Holocene warming interval, the climate gradually cooled over the next three thousand years or so, resulting in more extensive sea-ice cover in the bay. But the researchers find no evidence that the ice advanced in Maxwell Bay during the so-called Little Ice Age in the sixteenth to mid-nineteenth century.

The Antarctic Peninsula area has warmed 3 °C in the past five decades, with increased rainfall and a widespread retreat of glaciers. "Atmospheric warming trends linked to global climate change are an obvious culprit for the observed regional climate changes," say the researchers.

The study was supported by the US National Science Foundation Office of Polar Programs.

The authors are: K. T. Milliken and J. B. Anderson (Rice University), J.S. Wellner (University of Houston), S.M. Bohaty (NOCS/SOES) and P.L. Manley (Middlebury College, Vermont).

Publication:

Milliken, K. T., et al. High-resolution Holocene climate record from Maxwell Bay, South Shetland Islands, Antarctica. Geological Society of America Bulletin 121, 1711-1725 (2009).

http://gsabulletin.gsapubs.org/content/121/11-12/1711

The National Oceanography Centre, Southampton is the UK's focus for ocean science. It is one of the world's leading institutions devoted to research, teaching and technology development in ocean and Earth science. Over 500 research scientists, lecturing, support and seagoing staff are based at the centre's purpose-built waterside campus in Southampton along with over 700 undergraduate and postgraduate students.

The National Oceanography Centre, Southampton is a collaboration between the University of Southampton and the Natural Environment Research Council. The NERC royal research ships RRS James Cook and RRS Discovery are based at NOCS as is the National Marine Equipment Pool which includes Autosub and Isis, two of the world's deepest diving research vehicles.

Dr. Rory Howlett | EurekAlert!
Further information:
http://www.soton.ac.uk

More articles from Earth Sciences:

nachricht 558 million-year-old fat reveals earliest known animal
21.09.2018 | Max-Planck-Institut für Biogeochemie

nachricht Glacial engineering could limit sea-level rise, if we get our emissions under control
20.09.2018 | European Geosciences 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: Scientists present new observations to understand the phase transition in quantum chromodynamics

The building blocks of matter in our universe were formed in the first 10 microseconds of its existence, according to the currently accepted scientific picture. After the Big Bang about 13.7 billion years ago, matter consisted mainly of quarks and gluons, two types of elementary particles whose interactions are governed by quantum chromodynamics (QCD), the theory of strong interaction. In the early universe, these particles moved (nearly) freely in a quark-gluon plasma.

This is a joint press release of University Muenster and Heidelberg as well as the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt.

Then, in a phase transition, they combined and formed hadrons, among them the building blocks of atomic nuclei, protons and neutrons. In the current issue of...

Im Focus: Patented nanostructure for solar cells: Rough optics, smooth surface

Thin-film solar cells made of crystalline silicon are inexpensive and achieve efficiencies of a good 14 percent. However, they could do even better if their shiny surfaces reflected less light. A team led by Prof. Christiane Becker from the Helmholtz-Zentrum Berlin (HZB) has now patented a sophisticated new solution to this problem.

"It is not enough simply to bring more light into the cell," says Christiane Becker. Such surface structures can even ultimately reduce the efficiency by...

Im Focus: New soft coral species discovered in Panama

A study in the journal Bulletin of Marine Science describes a new, blood-red species of octocoral found in Panama. The species in the genus Thesea was discovered in the threatened low-light reef environment on Hannibal Bank, 60 kilometers off mainland Pacific Panama, by researchers at the Smithsonian Tropical Research Institute in Panama (STRI) and the Centro de Investigación en Ciencias del Mar y Limnología (CIMAR) at the University of Costa Rica.

Scientists established the new species, Thesea dalioi, by comparing its physical traits, such as branch thickness and the bright red colony color, with the...

Im Focus: New devices based on rust could reduce excess heat in computers

Physicists explore long-distance information transmission in antiferromagnetic iron oxide

Scientists have succeeded in observing the first long-distance transfer of information in a magnetic group of materials known as antiferromagnets.

Im Focus: Finding Nemo's genes

An international team of researchers has mapped Nemo's genome

An international team of researchers has mapped Nemo's genome, providing the research community with an invaluable resource to decode the response of fish to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

"Boston calling": TU Berlin and the Weizenbaum Institute organize a conference in USA

21.09.2018 | Event News

One of the world’s most prominent strategic forums for global health held in Berlin in October 2018

03.09.2018 | Event News

4th Intelligent Materials - European Symposium on Intelligent Materials

27.08.2018 | Event News

 
Latest News

Astrophysicists measure precise rotation pattern of sun-like stars for the first time

21.09.2018 | Physics and Astronomy

Brought to light – chromobodies reveal changes in endogenous protein concentration in living cells

21.09.2018 | Life Sciences

"Boston calling": TU Berlin and the Weizenbaum Institute organize a conference in USA

21.09.2018 | Event News

VideoLinks
Science & Research
Overview of more VideoLinks >>>