Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Closing the Case on an Ancient Archeological Mystery

29.04.2015

Solving 4,000-year-old mystery helps WSU archeologist find useful resource for a warmer future

Climate change may be responsible for the abrupt collapse of civilization on the fringes of the Tibetan Plateau around 2000 B.C.


Barley cultivation in Jiuzhaigou National Park hasn't changed much in nearly 2,000 years. The park is located in the Min Shan mountain range, Northern Sichuan in South Western China.

Credit: Washington State University

WSU archaeologist Jade D'Alpoim Guedes and an international team of researchers found that cooling global temperatures at the end of the Holocene Climatic Optimum, a 4,000 year period of warm weather, would have made it impossible for ancient people on the Tibetan Plateau to cultivate millet, their primary food source.

Guedes' team's research recently was published online in the Proceedings of the National Academy of Sciences. Her results provide the first convincing explanation for why the area's original inhabitants either left or so abruptly changed their lifestyles.

They also help explain the success of farmers who practiced wheat and barley agriculture in the region 300 years later.

Unlike millet, wheat and barley have high frost tolerance and a low heat requirement, making them ideally suited for the high altitudes and cold weather of eastern Tibet. Guedes argues this made the two crops an important facet of subsistence immediately after their introduction around 1700 B.C.

"Wheat and barley came in at the opportune moment, right when millets were losing their ability to be grown on the Tibetan Plateau," Guedes said. "It was a really exciting pattern to notice. The introduction of wheat and barley really enabled Tibetan culture to take the form it has today, and their unique growth patterns may have played a crucial rule in the spread of these crops as staples across the vast region of East Asia."

One offshoot of the research: The ancient millet seeds that fell out of cultivation on the Tibetan Plateau as the climate got colder might soon be useful again as the climate warms up.

"Right now, these millets have almost become forgotten crops," Guedes said. "But due to their heat tolerance and high nutritional value, they may be once again be useful resources for a warmer future."

An archaeological enigma

At Ashaonao, Haimenkou, and other archeological sites in the Tibetan highlands, researchers for years had noticed a growing trend. An abundance of ancient wheat and barley seeds found at the sites suggested the crops rapidly replaced millet as the staple food source of the region during the second millennium BCE.

The findings were puzzling considering that the scientific consensus of the time was the region's climate would have actually favored millet, due to its shorter growing season, over wheat or barley.

The conundrum intrigued Guedes so she dove into the agronomy literature to investigate. She found agronomists tended to use a different measurement than archaeologists to determine whether crops can grow in cold, high altitude environments like the Tibetan Plateau. They used total growing degree days or the accumulated amount of heat plants need over their lifetime rather than the length of a growing season.

"My colleagues and I created a new model based off what we found in the literature," Guedes said. "It revealed that global cooling would have made it impossible to grow millet in the Eastern Tibetan Highlands at this time but would have been amenable to growing wheat and barley. Our work turned over previous assumptions and explained why millet is no longer a staple crop in the area after 2000 BCE."

Guedes' work points to climate cooling as the culprit behind the collapse of early civilization on the Tibetan Plateau. Ironically, the region is today one of the areas experiencing the most rapid climate warming on the planet. There are some areas in the southeastern plateau where temperatures are 6 degrees Celsius higher than they were 200 years ago.

Rapid temperature increase is making it difficult for the region's inhabitants to raise and breed yaks, a staple form of subsistence in the central Asian highlands, and grow cold weather crops, once again endangering their survival.

"So now we have a complete reversal and climate warming is having a big impact on the livelihood of smaller farmers on the Tibetan Plateau," Guedes said.

Media Contact

Jade D'Alpoim Guedes
jade.dalpoimguedes@wsu.edu
509-335-2304

 @WSUNews

http://www.wsu.edu 

Jade D'Alpoim Guedes | EurekAlert!

Further reports about: Mystery Tibetan barley climate warming crops food source growing season temperatures

More articles from Earth Sciences:

nachricht Live from the ocean research vessel Atlantis
13.12.2018 | National Science Foundation

nachricht NSF-supported scientists present new research results on Earth's critical zone
13.12.2018 | National Science Foundation

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Data use draining your battery? Tiny device to speed up memory while also saving power

The more objects we make "smart," from watches to entire buildings, the greater the need for these devices to store and retrieve massive amounts of data quickly without consuming too much power.

Millions of new memory cells could be part of a computer chip and provide that speed and energy savings, thanks to the discovery of a previously unobserved...

Im Focus: An energy-efficient way to stay warm: Sew high-tech heating patches to your clothes

Personal patches could reduce energy waste in buildings, Rutgers-led study says

What if, instead of turning up the thermostat, you could warm up with high-tech, flexible patches sewn into your clothes - while significantly reducing your...

Im Focus: Lethal combination: Drug cocktail turns off the juice to cancer cells

A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.

The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...

Im Focus: New Foldable Drone Flies through Narrow Holes in Rescue Missions

A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.

Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...

Im Focus: Topological material switched off and on for the first time

Key advance for future topological transistors

Over the last decade, there has been much excitement about the discovery, recognised by the Nobel Prize in Physics only two years ago, that there are two types...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

ICTM Conference 2019: Digitization emerges as an engineering trend for turbomachinery construction

12.12.2018 | Event News

New Plastics Economy Investor Forum - Meeting Point for Innovations

10.12.2018 | Event News

EGU 2019 meeting: Media registration now open

06.12.2018 | Event News

 
Latest News

Data use draining your battery? Tiny device to speed up memory while also saving power

14.12.2018 | Power and Electrical Engineering

Tangled magnetic fields power cosmic particle accelerators

14.12.2018 | Physics and Astronomy

In search of missing worlds, Hubble finds a fast evaporating exoplanet

14.12.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>