Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Climate dents in humankind´s family tree: new correlations discovered

06.12.2011
Climate changes in Earth’s history have influenced the fate of modern man´s ancestors, but until now it has not been clear why some evolutionary variations developed or disappeared.

Scientists of the Potsdam Institute for Climate Impact Research (PIK) and Potsdam University have now provided a novel view on human evolution during the past five million years. A nonlinear statistical analysis of sediments taken from the seafloor near Africa indicates that abrupt changes in climate variability could have had a significant impact on human evolution. In the first instance, the scientists have spotted three primeval tipping points.

“It has long been assumed that climate changes are significant for the history of humankind, but until now this has not been statistically proven,” says Jonathan Donges from PIK, lead author of the study published this week in the renowned Proceedings of the National Academy of Sciences. Now some evidence has been demonstrated. “For the first time we can show that the concurrence between changes in climate variability and those in early human evolution were probably not arbitrary,” says Donges. The transition between times of little and strong climatic fluctuations – “the changes within changes”– is crucial. Apparently they raise selection pressure.

Dust from the ocean bottom supplies data

Instead of long-term trends, the scientists examined comparably short-term changes that still cover a few thousand years. The mathematical analysis of time series spanning millions of years was based on data already published several years ago by marine geologists. The data is derived from drill cores from the seafloor of the Indian and Atlantic Oceans as well as the Mediterranean. The deposits of desert dusts contained in these sediments allow conclusions on what kind of climate prevailed at certain points in time.

In the process, the scientists were able to identify some of the mechanisms that possibly triggered climate changes. For example, the warm waters flowing from the Pacific towards Africa diminished due to shifting landmasses in the region of today´s Indonesia. Since ocean currents are conveyers of heat, as a result regional temperatures and rainfall over Africa changed. This in turn had impacts on the local vegetation and therefore also animal populations as well as early humans like Australopithecus, who became extinct about a million years ago. In contrast, other ancestors of man could suddenly flourish under the changed conditions, because they were more adaptive. “As an allrounder, Homo had better chances in a fluctuating climate than more specialized hominids,” says Donges.

Look into the past sharpens that into the future

To look into the past can help sharpen our view into the future. “Climate changes have impacts on the living conditions of humankind – and what took many hundreds of thousands of years in the past could now happen in fast motion because of the man-made greenhouse effect,” explains Jürgen Kurths, head of the research team and co-author of the study. Regarding temperatures, one of the three relevant periods about three million years ago can be considered a counterpart to a world with unabated CO2 emissions, such as may exist by the end of this century. “This is not a one-to-one equivalence, but about understanding essential mechanisms of climate changes,” says Kurths. “So-called paleoclimatology often serves to verify assumptions about the climate of today and tomorrow.”

“It is a big step ahead. Finally the methods of nonlinear physics are being utilized for research on the evolution of humankind,” says Hans Joachim Schellnhuber, PIK director and also one of the study´s co-authors. He is one of the pioneers in the application of this discipline – known as chaos theory – to Earth system research. “We are succeeding better and better in understanding complex dynamic systems,” says Schellnhuber. “It is becoming ever more clear that this is not a glass bead game, but an extraordinarily relevant field of research – especially in regard to climate change.”

Article: Donges, J., Donner, R.V., Trauth, M.H., Marwan, N., Schellnhuber, H.J., Kurths, J.: Nonlinear detection of paleoclimate-variability transitions possibly related to human evolution. Proceedings of the National Academy of Sciences [doi:10.1073/pnas.0709640104] (Early Edition)

The article is available in PNAS's Early Edition online the day it gets published this week. Until then it is available only on a protected website of PNAS/Eurekalert or via email: pnasnews@nas.edu.

For further information please contact the PIK press office:

Phone: +49 331 288 25 07
E-mail: press@pik-potsdam.de

Jonas Viering | PIK Potsdam
Further information:
http://www.pik-potsdam.de
http://www.pnas.org/content/early/recent

More articles from Earth Sciences:

nachricht Less radiation in inner Van Allen belt than previously believed
21.03.2017 | DOE/Los Alamos National Laboratory

nachricht Mars volcano, Earth's dinosaurs went extinct about the same time
21.03.2017 | NASA/Goddard Space Flight Center

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

Pulverizing electronic waste is green, clean -- and cold

22.03.2017 | Materials Sciences

Astronomers hazard a ride in a 'drifting carousel' to understand pulsating stars

22.03.2017 | Physics and Astronomy

New gel-like coating beefs up the performance of lithium-sulfur batteries

22.03.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>