Under climate stress, human innovation set stage for population surge
Research highlights importance of social resilience in Bronze Age China


Date:
February 26, 2021
Source:
Washington University in St. Louis
Summary:
Aridification in the central plains of China during the early Bronze
Age did not cause population collapse, a result that highlights
the importance of social resilience to climate change. Instead of
a collapse amid dry conditions, development of agriculture and
increasingly complex human social structures set the stage for
a dramatic increase in human population around 3,900 to 3,500
years ago.



FULL STORY ========================================================================== Climate alone is not a driver for human behavior. The choices that
people make in the face of changing conditions take place in a larger
human context. And studies that combine insights from archaeologists and environmental scientists can offer more nuanced lessons about how people
have responded -- sometimes successfully -- to long-term environmental
changes.


==========================================================================
One such study, from researchers at Washington University in St. Louis and
the Chinese Academy of Sciences, shows that aridification in the central
plains of China during the early Bronze Age did not cause population
collapse, a result that highlights the importance of social resilience
to climate change.

Instead of a collapse amid dry conditions, development of agriculture
and increasingly complex human social structures set the stage for a
dramatic increase in human population around 3,900 to 3,500 years ago.

"In China, especially, there has been a relatively simplistic view of the effects of climate," said Tristram R. "T.R." Kidder, the Edward S. and
Tedi Macias Professor of Anthropology in Arts & Sciences. The new study
was posted online in Environmental Research Letters.

"Our work shows that we need to have a nuanced appreciation of human
resilience as we consider the effects of climate and its effects on
human societies," Kidder said. "We have remarkable capacity to adapt. But
part of the lesson here is that our social, political and technological
systems have to be flexible.

"People in the past were able to overcome climate adversity because they
were willing to change," he said.



==========================================================================
The new study is one of the first attempts to quantify the types and rates
of demographic and subsistence changes over the course of thousands of
years in the central plains of China.

By combining information about climate, archaeology and vegetation, the
authors mapped out an ambitious story about what changed, when it changed
and how those changes were related to human social structures at the time.

Researchers used pollen data from a lake sediment core collected in Henan Province to interpret historical climate conditions. In this area, they
found that a warm and wet climate about 9,000 to 4,000 years ago shifted
to a cool and dry climate during the Neolithic-Bronze Age transition
(about 4,000 to 3,700 years ago). The researchers then used radiocarbon
dating and other archaeological data to determine what people were growing
and eating during periods of significant population surges and declines
in this timeframe.

Confronted with the fluctuation and limitation of resources caused
by episodes of climatic aridification, people expanded the number of
plants they cultivated for food, the researchers found. They embraced
new diversity in agriculture - - including foxtail millet, broomcorn
millet, wheat, soybean and rice -- all of which reduced the risks of
food production.

This also was a time marked by innovations in water management approaches
for irrigation, as well as new metal tools. Social structures also shifted
to accommodate and accelerate these examples of human adaptive ingenuity.



========================================================================== "Certainly, by 4,000 years ago, which is when we see this change in the
overall environmental condition, this is a society with complicated
political, social and economic institutions," Kidder said. "And what
I think we are seeing is the capacity of these institutions to buffer
and to deal with the climatic variation. When we talk about changes in subsistence strategies, these changes didn't happen automatically. These
are human choices." With this and other related research work, Kidder
has argued that early Chinese cities provide an important context that
closely resembles modern cities, where high-density urbanism is supported
by intensive agriculture. They provide a better historical analog than
the Maya world or those in southeast Asia, notably Angkor Wat and the
Khmer Kingdom. Those were cities where lower density and food production
did not put the same sorts of demands on the physical environment.

Lead author Ren Xiaolin, assistant professor at the Institute for the
History of Natural Sciences at the Chinese Academy of Sciences in Beijing, worked closely with Kidder and others in his laboratory to develop the
theory and framework for how to think about environmental changes and
urbanism in China.

"Climate change does not always equal collapse -- and this is an important point in both a prehistoric and modern context," said Michael Storozum,
another co-author and research fellow at The Hebrew University of
Jerusalem. Storozum is a PhD graduate of Washington University, where
he studied under Kidder.

"Humans have been heavily modifying their environments for thousands of
years, often in the pursuit of increasing food production which grants societies a higher degree of social resilience," Storozum said.

He draws connections between the findings from this paper and his current research as part of The Wall project, a study of people and ecology in
medieval Mongolia and China.

"As more environmental scientists and archaeologists work together,
I expect that our understanding of what makes a society resilient to
climate change in prehistoric and historical times will grow as well,"
Storozum said.

Kidder added: "We need to think carefully about how we
understand the capacity of people to change their world." ========================================================================== Story Source: Materials provided by
Washington_University_in_St._Louis. Original written by Talia
Ogliore. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Xiaolin Ren, Junjie Xu, Hui Wang, Michael Storozum, Peng Lu,
Duowen Mo,
Tuoyu Li, Jianguo Xiong, Tristram R. Kidder. Holocene fluctuations
in vegetation and human population demonstrate social resilience
in the prehistory of the Central Plains of China. Environmental
Research Letters, 2021; DOI: 10.1088/1748-9326/abdf0a ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/02/210226121247.htm

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