Free Newsletters - Space News - Defense Alert - Environment Report - Energy Monitor
. 24/7 Space News .




ICE WORLD
Warm Climate - Cold Arctic?
by Staff Writers
Kiel, Germany (SPX) Jun 19, 2012


The average Sea Surface Temperatures (SST) of the modern northern Atlantic and the Norwegian Sea. The map clearly shows the heat transport into the high latitudes. Graphic: H. Bauch, AdW Mainz/GEOMAR.

The Eemian interglacial period that began some 125,000 years ago is often used as a model for contemporary climate change. In the international journal "Geophysical Research Letters" scientists from Mainz, Kiel and Potsdam (Germany) now present evidence that the Eemian differed in essential details from modern climatic conditions.

To address the question about how climate may develop in the future, earth scientists direct their attention to the past. They look for epochs with similar conditions to today. The major identified climatic processes are then simulated with numerical models to further test possible reactions of the Earths' system.

An epoch which is often regarded suitable for such an undertaking is the Eemian warm period, which began around 125,000 years ago following the Saalian ice age. For about 10,000 years, average temperatures on Earth in the Eemian were rather enhanced - probably several degrees above today's level. This seems to be well documented in both ice cores as well as terrestrial records from land vegetation.

Substantial parts of the Greenland ice had melted, and global sea level was higher than today. "Therefore, the Eemian time is suited apparently so well as a basis for the topical issue of climate change", says Dr Henning Bauch, who works for the Academy of the Sciences and the Literature Mainz (AdW Mainz) at GEOMAR | Helmholtz Centre for Ocean Research Kiel.

However, in a study which appears in the recent issue of the international journal "Geophysical Research Letters" Dr Bauch, Dr Evgeniya Kandiano of GEOMAR as well as Dr Jan Helmke of the Institute for Advanced Sustainability Studies in Potsdam now show that the Eemian warm period differed from the present day situation in one critical aspect - the development in the Arctic Ocean.

In our current warm period, also called Holocene, oceanic and atmospheric circulation delivers large amounts of heat northward into the high latitudes. The most well known heat conveyer is the Gulf Stream and its northern prolongation called the North Atlantic Drift. The currents provide not only the pleasant temperatures in Northern Europe, they also reach as far as the Arctic.

Studies in the last years have shown that the oceanic heat transport to the Arctic has even increased, while the summer sea ice cover in the Arctic Ocean seems to be decreasing continuously. It has long been assumed that such conditions also prevailed 125,000 years ago. Accordingly, the Arctic should have been by and large ice-free in the Eemian summers.

Dr Bauch's group examined sediment cores from the seabed in which information about the climate history of the past 500,000 years is stored. These come from the Atlantic to the west of Ireland and from the central Nordic Seas to the east of the island of Jan Mayen.

The sediments contain minute calcite tests of dead microorganisms (foraminifers). "The type of species assemblage in the respective layers as well as the isotopic composition of the calcitic tests give us information about temperature and other properties of the water in which they lived at that time", explains Dr Bauch.

The samples from the Atlantic delivered the higher-than-Holocene temperature signals so typical for the Eemian. The tests from the Nordic Seas, however, tell quite another story. "The found foraminifers of Eemian time indicate comparatively cold conditions". The isotope investigations of the tests, in combination with previous studies of the group, "indicate major contrasts between the ocean surfaces of these two regions ", according to Dr Bauch.

"Obviously, the warm Atlantic surface current was weaker in the high latitude during the Eemian than today." His explanation: "The Saalian glaciation which preceded the Eemian was of much bigger extent in Northern Europe than during the Weichselian, the ice age period before our present warm interval. Therefore, more fresh water from the melting Saalian ice sheets poured into the Nordic Seas, and for a longer period of time.

This situation had three consequences: The oceanic circulation in the north was reduced, and winter sea ice was more likely to form because of lower salinity. At the same time, this situation led to a kind of 'overheating' in the North Atlantic due to a continuing transfer of ocean heat from the south."

On the one hand, the study introduces new views on the Eemian climate. On the other hand, the new results have consequences for climatology in general: "Obviously, some decisive processes in the Eemian ran off differently, like the transfer of ocean warmth towards the Arctic. Models should take this into consideration if they want to forecast the future climate development on the basis of past analogues like the Eemian ", says Dr Bauch.

Bauch, H. A., E. S. Kandiano, J. P. Helmke (2012): Contrasting ocean changes between the subpolar and polar North Atlantic during the past 135 ka. Geophysical Research Letters, 39, 2012, http://dx.doi.org/10.1029/2012GL051800. Related News: Atlantic Water Warms the Arctic Files: pm_2012_46_Eem-NorwegianSea_en.pdf41 K

.


Related Links
GEOMAR
Academy of the Sciences and the Literature Mainz (AdW Mainz)
The Institute for Advanced Sustainability Studies Potsdam
Beyond the Ice Age






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





ICE WORLD
Spanish Scientist Participate in the Most Comprehensive Study Ever Done on Ice
Viernes, Spain (SPX) Jun 19, 2012
A group composed of 17 scientists from 11 different countries has published the most comprehensive study ever done on ice in the world. The study addresses the most important contemporary issues in a field of research that is "red hot", in authors' words. This study, which was recently published in the prestigious journal Reviews of Modern Physics reviews recent international research stud ... read more


ICE WORLD
Nanoparticles found in moon glass bubbles explain weird lunar soil behaviour

UA Lunar-Mining Team Wins National Contest

NASA Lunar Spacecraft Complete Prime Mission Ahead of Schedule

NASA Offers Guidelines To Protect Historic Sites On The Moon

ICE WORLD
Opportunity Faces Slow Going Due To Communication Issues

Test of Spare Wheel Puts Odyssey on Path to Recovery

Impact atlas catalogs over 635,000 Martian craters

e2v imaging sensors launched into space on NASA mission to Mars

ICE WORLD
West must cut appetite for cars and TVs, says UN official

Flying to space is also women's work: Russian cosmonaut

Data From Voyager 1 Points To Interstellar Future

The pressure is on for aquanauts

ICE WORLD
Liu Yang: China's first female astronaut

Contingency plans to address 700 space scenarios

China's manned space mission "hits target": Russian expert

China astronauts enter space module for first time

ICE WORLD
Varied Views from the ISS

Strange Geometry - Yes, It's All About the Math

Capillarity in Space - Then and Now, 1962-2012

Dragon on board

ICE WORLD
NASA Administrator Bolden Views Historic SpaceX Dragon Capsule

NASA's NuSTAR Mission Lifts Off

Orbital Launches Company-Built NuSTAR Satellite Aboard Pegasus Rocket for NASA

NuSTAR Arrives at Island Launch Site

ICE WORLD
Extremely little telescope discovers pair of odd planets

Alien Earths Could Form Earlier than Expected

Planets can form around different types of stars

Small Planets Don't Need 'Heavy Metal' Stars to Form

ICE WORLD
Lockheed Martin ATC Delivers Flight Hardware For Magnetospheric Multiscale Mission

Boeing Completes CDR of MEXSAT Geomobile Satellite System

Panasonic's first Android-based 'toughpad' unveiled in Asia

Microsoft tablet computer a big bet on future: analysts




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement