Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Major climate change occurred 5,200 years ago: Evidence suggests that history could repeat itself

16.12.2004


Glaciologist Lonnie Thompson worries that he may have found clues that show history repeating itself, and if he is right, the result could have important implications to modern society.

Thompson has spent his career trekking to the far corners of the world to find remote ice fields and then bring back cores drilled from their centers. Within those cores are the records of ancient climate from across the globe. From the mountains of data drawn by analyzing countless ice cores, and a meticulous review of sometimes obscure historic records, Thompson and his research team at Ohio State University are convinced that the global climate has changed dramatically. But more importantly, they believe it has happened at least once before, and the results were nearly catastrophic to emerging cultures at the time. He outlined his interpretations and fears today at the annual meeting of the American Geophysical Union in San Francisco.

A professor of geological sciences at Ohio State and a researcher with the Byrd Polar Research Center, Thompson points to markers in numerous records suggesting that the climate was altered suddenly some 5,200 years ago with severe impacts. He points to perfectly preserved plants he discovered that recently emerged from the Quelccaya ice cap in the Peruvian Andes as that glacier retreats. This monstrous glacier, some 551 feet (168 meters) deep, has shown an exponentially increasing rate of retreat since his first observations in 1963. The plants were carbon-dated to determine their age and tests indicated they had been buried by the ice for perhaps 5,200 years. That suggests that somehow, the climate had shifted suddenly and severely to capture the plants and preserve them until now.



In 1991, hikers found the preserved body of a man trapped in an Alpine glacier and freed as it retreated. Later tests showed that the human – dubbed Oetzi – became trapped and died around 5,200 years ago. Thompson points to a study of tree rings from Ireland and England that span a period of 7,000 years. The point in that record when the tree rings were narrowest – suggesting the driest period experienced by the trees – was approximately 5,200 years ago.

He points to ice core records showing the ratio of two oxygen isotopes retrieved from the ice fields atop Africa’s Mount Kilimanjaro. A proxy for atmospheric temperature at the time snow fell, the records are at their lowest 5,200 years before now. He lists the shift by the Sahara Desert from a habitable region to a barren desert; major changes in plant pollen uncovered from lakebed cores in South America, and the record lowest levels of methane retrieved from ice cores from Greenland and Antarctica and all occurred at the same time – 5,200 years ago.

“Something happened back at this time and it was monumental,” Thompson said. “But it didn’t seem monumental to humans then because there were only approximately 250 million people occupying the planet, compared to the 6.4 billion we now have. “The evidence clearly points back to this point in history and to some event that occurred. It also points to similar changes occurring in today’s climate as well,” he said.“To me, these are things we really need to be concerned about.”

The impact of a climate change of that magnitude on a modern world would be tremendous, he said. Seventy percent of the population lives in the world’s tropics and major climate changes would directly impact most of them.

Thompson believes that the 5,200-year old event may have been caused by a dramatic fluctuation in solar energy reaching the earth. Scientists know that a historic global cooling called the Little Ice Age, from 1450 to 1850 A.D., coincided with two periods of decreased solar activity.

Evidence shows that around 5,200 years ago, solar output first dropped precipitously and then surged over a short period. It is this huge solar energy oscillation that Thompson believes may have triggered the climate change he sees in all those records. “The climate system is remarkably sensitive to natural variability,” he said. “It’s likely that it is equally sensitive to effects brought on by human activity, changes like increased greenhouse gases, altered land-use policies and fossil-fuel dependence. “Any prudent person would agree that we don’t yet understand the complexities with the climate system and, since we don’t, we should be extremely cautious in how much we ‘tweak’ the system,” he said.

“The evidence is clear that a major climate change is underway.”

Lonnie Thompson | EurekAlert!
Further information:
http://www.osu.edu

More articles from Ecology, The Environment and Conservation:

nachricht Litter is present throughout the world’s oceans: 1,220 species affected
27.03.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

nachricht International network connects experimental research in European waters
21.03.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)

All articles from Ecology, The Environment and Conservation >>>

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

Big data approach to predict protein structure

27.03.2017 | Life Sciences

Parallel computation provides deeper insight into brain function

27.03.2017 | Life Sciences

Weather extremes: Humans likely influence giant airstreams

27.03.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>