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 NASA finds newly formed tropical storm lan over open waters
17.10.2017 | NASA/Goddard Space Flight Center

nachricht The melting ice makes the sea around Greenland less saline
16.10.2017 | Aarhus 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: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Osaka university researchers make the slipperiest surfaces adhesive

18.10.2017 | Materials Sciences

Space radiation won't stop NASA's human exploration

18.10.2017 | Physics and Astronomy

Los Alamos researchers and supercomputers help interpret the latest LIGO findings

18.10.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>