Could climate change have influenced the rise of a mysterious civilization over 5,000 years ago?

In 2001, archaeologists uncovered an astonishing discovery in Peru: enormous man-made structures, spanning hundreds of feet, constructed from stone and dirt. These massive mounds were scattered across the dry valleys of Peru's Norte Chico region, stretching from the Andes Mountains to the Pacific coast.

While mounds have been discovered in Peru before, these ones stand out. They could change the way we understand the origins of civilization in the Americas.

The mounds resemble flat-topped pyramids, some reaching up to 85 feet (26 meters) tall [source: ScienceDaily]. Though these structures may not rival the grandeur of the pyramids built by the Maya or the Incas—being smaller and less imposing—they are actually older than any large-scale structures associated with these empires. These mounds are even older than the Egyptian pyramids, suggesting that the builders of Norte Chico may have been the first complex civilization in the Americas.

The recently uncovered mounds, estimated to be around 5,000 years old, predate the early Mayan civilization by possibly a thousand years [sources: Joyce, Lovgren]. What is even more striking, however, is their location in Peru. Civilizations typically rise in places rich with resources, where access to water and food supplies is abundant. But the Norte Chico region of Peru is barren. The archaeologists were working in an area that seems entirely uninhabitable. The land is dry, with scarce water sources and virtually no vegetation in sight.

Why would an advanced civilization emerge in such a lifeless region? How could the builders of these mounds have not only survived but thrived, even creating a new way of life in the Americas?

According to the team of archaeologists who uncovered the mounds, the answer might lie in something we are all familiar with today: climate change.

The story begins with the discovery of seashells in a nearly waterless expanse of Peru.

The Mound Builders

When a group of archaeologists uncovered dozens of massive mounds hidden in the arid valleys of Norte Chico, it raised a flurry of questions.

Archaeologists not only struggled to link the mounds to any known South American civilizations, but they also found no other usual traces of a civilization with architectural sophistication. This might explain why this mysterious culture went unnoticed for so long.

However, they did discover something that opened up an entirely new mystery: seashells and fish bones.

Why would there be traces of marine life in a desert landscape? One plausible explanation is a theory regarding the origins of the mound-building civilization 5,000 years ago: The mound builders were fishermen who were forced to migrate inland when climate change disrupted their way of life.

The archaeologists behind this discovery are continuing their work to support the climate-change hypothesis. They are examining the rings in seashells to gather proof of shifting ocean temperatures. The proposed theory is as follows:

Around 5,000 years ago, fishermen flourished along Peru's coastline, roughly 10 miles (16 kilometers) from the Norte Chico area. These hunter-gatherers relied on the ocean for sustenance. However, something shifted abruptly around 3000 B.C. [source: Joyce]. A change in the climate, linked to altered interactions between the atmosphere and the sea, jeopardized the sustainability of their fishing lifestyle.

The change likely occurred through a rise in the frequency of El Niño weather systems. El Niño is a cyclical climate phenomenon that brings heavy rainfall and warmer ocean temperatures to South America. This event is linked to the timing and duration of hurricane seasons and can impact flooding, temperatures, and marine life. If it occurs more often than usual, it can have severe effects on coastal communities. Rising ocean temperatures would disrupt the distribution of sea life, while the relentless rains would cause flooding.

As a result, the fishermen moved inland, abandoning their hunter-gatherer way of life. To adapt, they sought new sources of food. What appears today as barren land was once fertile, thanks to the climate changes. With an abundance of water, irrigation became a simple solution, and they turned to farming. They traded their crops with those who remained on the coast and continued fishing, which explains the fish bones and seashells found in the area.

This form of organized food production and resource trading likely led to the development of a centralized society. They built permanent homes and sunken plazas for communal gatherings. The mound builders appeared to have had a structured government and religion.

The civilization flourished for approximately a thousand years [source: ScienceDaily]. Geological evidence suggests its downfall mirrored its rise: a climatic shift that made irrigation increasingly difficult, prompting the mound builders to relocate to more fertile regions, leaving their once-thriving world behind.

With the entire world facing the potential consequences of climate change, the discovery of the mound builder civilization may offer valuable insights. This isn't the first society believed to have been drastically affected by changes in weather patterns. The collapse of China's Tang Dynasty in 907 A.D. is thought to be connected to a shift in the monsoon, leading to prolonged drought. Around the same period, the Mayan civilization fell due to a series of droughts that drained their water sources. The common factor seems to be a resistance to adaptation. It’s a straightforward conclusion: an agriculture-dependent society falters in the face of water scarcity, while a society that adapts – perhaps shifting from agricultural practices to trade – stands a better chance of surviving a climate crisis that threatens its survival.