•Archaeologists and geographers have been trying to estimate the pre-1492 American population for decades. But this is a very difficult task. When Christopher Columbus set foot on the island now known as San Salvador in the Bahamas on Oct. 12, 1492, he encountered the natives who lived there, and who traded with him and other groups living on nearby islands, as he described in his journal. But just a few decades after Columbus’s arrival, the Native Americans, as anthropologist Eric Wolf described them, declined rapidly due to a combination of epidemic disease, warfare and enslavement.
One of the first modern researchers to attempt to quantify the pre-Columbian indigenous population was the anthropologist Dobyns. In one study, Dobyns used estimates of how many people different land types could support and records of epidemics in the 16th century to arrive at an estimated indigenous population of about 112 million — more than 100 times higher than some earlier experts believed. “In summary, Dobyns filled the land to its maximum carrying capacity, so that all similar lands environmentally were populated with the same number of people,” said Milner. “He also assumed that the epidemic was widespread and universal; this would make sense if the land was full.”
In one study, Milner and the geographer Chaplin focused on data from eastern North America; by compiling historical group sizes and the sizes of archaeological settlements, they estimated the location and size of “population communities.” Using this method, their general estimate for eastern U.S. and southeastern Canada was about 1.6 million people. Milner and Chaplin wrote: “Our average estimates suggest that North America, before the dramatic reduction of the indigenous population by European diseases in the early 16th century, contained roughly between 2.8 and 5.7 million people, or ‘best estimate’ of 3.8 million.”
“If you’re going to start calculating specific populations, you have to use measurements that work across regions,” said the researcher, an archaeologist at the University of Wyoming, to Live Science. “People produce things that are ubiquitous, because everyone needs to make fire to keep warm and cook food.”
Charred wood is one of the main human-made things that archaeologists use to date an area with radiocarbon. Radiocarbon data provide a series of dates that suggest the wood was likely used.
In North America, many carbon-14 dates from charred wood, along with animal bones and plant remains from archaeological sites, were recorded in CARD (North American Radiocarbon Data Bank).
In one study, geographer Peros and his co-authors at Bishop’s University mathematically combined the ranges of radiocarbon dates in CARD to produce a single curve that showed how common C-14 dates were at the time. At that time, CARD contained about 25,000 records.
Periods with more people likely produced more material that could be radiocarbon-dated, so the shape of the radiocarbon date curve gave the team an idea of when North America’s population was growing and declining. They found that the North American population grew rapidly around 50 B.C. and peaked around A.D. 1150. Before that, the indigenous population was likely declining; this may have been because people were moving into denser settlements, possibly due to increased deaths from diseases such as tuberculosis.
“The 1150 date was a surprising and interesting finding,” Peros told Live Science. “I was expecting that to be around 1500, following the arrival of Europeans.”
In one study, Kelly and his co-authors found a similar peak time. By that time, CARD’s dataset had grown, making the estimates more robust. In the study, the researchers wrote: “Although the indigenous population was decimated by contact with Europeans, it simply peaked in size around 1500 CE and did not decline thereafter.” In fact, they found evidence of a slight uptick in the population count just before 1500.
“World population has more than doubled in my lifetime; this has never been seen in human existence,” said Milner. “Environmental scientists are trying to look at what happened over long time scales to give us a range of what might happen in the future. We need to make some conscious decisions about how we manage our landscape and adapt to these changes.”
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