Climate shifts drove human innovation 600,000 years ago in China

Geographical distribution of 95 archaeological sites from the Early and Middle Pleistocene with numerical age estimates in China. (CREDIT: MDPI)

Far in the rolling highlands of north China, a serene basin once held one of mankind's best survival stories. The Nihewan Basin, a dry semi-arid region filled with ancient lakebeds, has been a bonanza for archaeologists trying to figure out how early man survived a changed world.

And now, a fresh study of the Jijiazhuang site, or JJZ, brings us a picture of the ingenuity and resourcefulness of our Middle Pleistocene forebears, who inhabited this realm from 630,000 to 490,000 years ago.

Reading Clues in Ancient Sediments

The research team from the Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, pieced together the surrounding environment using a range of methods. The researchers analyzed sediment grains, color changes, elemental composition, and fossilized pollen to create a detailed ecological chronology. They mapped out five broad stages of environmental evolution at the JJZ locality.

Schematic map showing the Nihewan Basin and mentioned Paleolithic sites. (CREDIT: Scientific Reports)

What evolved was a landscape of fluctuating climates. Cold, damp conditions yielded to drier, warmer intervals. Pine and spruce woodlands turned into open grasslands. The water levels in the lakes adjusted with them, generating either a wooded, productive landscape or a rolling, grassy plain. These ever-changing environments posed challenges and advantages to the hominins that inhabited them.

A Window of Opportunity

Archaeologists discovered that people had occupied JJZ during one of the temperate periods, following retreat of the Nihewan paleolake and when woodland grassland blanketed the land. This supported a balanced mix of vegetation and game animals. It also occurred during a prolonged interglacial period known as Marine Isotope Stages 15 to 13, when northern climates were unusually warm and stable.

"By integrating environmental proxies and archaeological remains, our research demonstrates that climate was not just a background factor, but an active driver of human adaptation," concluded lead author Professor Shuwen Pei. He added that the results capture a pivotal moment when early humans adapted their approach to living and surviving in intricate and dynamic conditions.

Marine Isotope Stage (MIS) graph showing the chronology and amplitude of past climate intervals. Stage numbers in red indicate interglacial or interstadial warm episodes. Stage numbers in blue indicate glacial stadials. (CREDIT: Science Direct)

Tools, Bones, and a New Way of Living

The excavation yielded 255 stone implements ranging from precisely shaped cores to retouched tools and sharp-edged flakes. They were not mere rocks but carefully made cutting, scraping, and processing instruments. There were also 464 animal bones, predominantly horses, with clear cut marks and percussion marks. The markings told the tale of skinning, dismembering, and cracking bones to access the marrow.

What was notable about this discovery was raw material procurement. Rocks were brought in from 8 to 10 kilometers away, suggesting that these hominins ventured further afield to acquire premium materials. This wider network of foraging resources shattered the long-standing paradigm that tool manufacture in northern China remained unchanged over hundreds of thousands of years. Instead, it suggested flexibility and forward planning.

These efforts show that humans of that time were not in a rut technologically," the researchers said. "They were able to adapt their method to the world about them."

Climate and Innovation Hand in Hand

The Nihewan Basin has long been East Asia's most important archaeological area. Although previous studies focused on the Early Pleistocene, this new research puts the Middle Pleistocene in the foreground as the key turning point. In the area, Homo erectus and sister clades faced fluctuating climates but were capable of innovating. The extended warmth during interglacial periods created a key window of opportunity to play around with new ideas, from refining stone tools to expanding diets.

Hominin timeline across eras. (CREDIT: Wikimedia / CC BY-SA 4.0)

Collectively, the evidence suggests that long-term mild phases acted as launch pads for human innovativeness. Interglacial "windows of opportunity" created the incentive for experimentation and tenacity, traits which would echo across subsequent human development.

Lessons From the Deep Past

The work done at JJZ helps add to growing evidence that proves environmental change had a direct impact on the path of human history. The research points out the way climatic pressures caused humans not only to develop but also to plan, diversify resources, and come up with their tools.

The story is also relevant today. Just like their ancient counterparts in northern China, modern societies today are faced with the whims of global climate change. The history of resilience in the past drives home the reality that flexibility has always been central to survival.

Practical Implications of the Research

This research demonstrates how protracted periods of climatic stability fostered technological advancement and enhanced survival strategies within early hominins.

By illuminating the ways in which early populations managed to negotiate innovation against environmental adversity, the research provides an example of how modern societies might respond to climatic stress.

These lessons in resilience and adaptability can be applied to resource usage and adaptive tactics in today's rapidly changing world.

Research findings are available online in the Journal of Geographical Sciences.