"The Great Dying of the Indigenous Peoples of the Americas resulted in a human-driven global impact on the Earth System in the two centuries prior to the Industrial Revolution"............."The arrival of Europeans in the Americas in 1492 CE marks the onset of disease epidemics resulting in the loss of up to 90% of indigenous people living in the Americas over the subsequent century"............"There is wide agreement about the effects of diseases and epidemics associated with European contact".............."The first well-documented, widespread epidemic in what was to become New Mexico was smallpox in 1636"..............."Shortly thereafter, measles entered the area, and many Pueblos lost as many as a quarter of their inhabitants"................."After the founding of Spanish settlements and missions, there was substantially more contact, and throughout the 17th century, epidemic disease was repeatedly imported"................"It should be noted that Osteologic data demonstrate that native groups were most definitely not living in a pristine, disease-free environment before contact".........."Diseases such as treponemiasis and tuberculosis were already present in the New World, along with diseases such as tularemia, giardia, rabies, amebic dysentery, hepatitis, herpes, pertussis, and poliomyelitis, although the prevalence of almost all of these was probably low in any given group"............."Old World diseases that were not present in the Americas until contact include bubonic plague, measles, smallpox, mumps, chickenpox, influenza, cholera, diphtheria, typhus, malaria, leprosy, and yellow fever"............. "Indians in the Americas had no acquired immunity to these infectious diseases"..............."Europeans began to colonize North America (defined here as the United States of America and Canada) after Central and South America, thus regional and continent wide estimates are largely based on archaeological evidence, tribe-by-tribe counts and environmental carrying capacities"............ "The lower range of population estimates for North America lies between 900,000 and 2.4 million, based on tribe-by-tribe counts for the period 1600 CE to mid-1800 CE"..............."The highest estimate of 18 million, established from analyzing environmental carrying capacities, has been criticized for its assumptions on food acquisition strategies".............."More recent estimates derived from geospatial interpolation of archaeological sites range between 2.8 million and 5.7 million"................."These intermediate figures are supported by a recent comprehensive regional-scale archaeological study"

https://www.sciencedirect.com/science/article/pii/S0277379118307261

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1071659/

Earth system impacts of the European arrival and Great Dying in the Americas after 1492

12/4/2018

Author links open overlay panelAlexanderKochahrisBrierleyaMark M.MaslinaSimon L.Lewis

The population of the Americas in 1492

The first population groups to arrive in North America between 20,000 and 15,000 years ago were of east Asian- and north Eurasian ancestry (e.g. Amick, 2017; Moreno-Mayar et al., 2018; Pedersen et al., 2016). The adoption of a sedentary, agricultural way of life in the Americas began 10,000–8000 BP (Piperno and Dillehay, 2008; Piperno et al., 2009). Large, complex civilizations emerged in North, Central and South America, further increasing population density, with abundant evidence for a large population living in the Americas prior to European arrival (e.g. Bolt and van Zanden, 2014; Canuto et al., 2018; Clement et al., 2015; Cook, 1998; Denevan, 1992a). However, as the epidemics spread, often ahead of the European explorers, pre-European population estimates were never formally documented in colonial censuses (Diamond, 1997; Dobyns, 1993). Hence, Native American populations were only documented in the decades after European contact, necessitating the use of indirect methods to estimate the pre-1492 population of the Americas. Here, we summarize all existing methodologies applied to reconstruct pre-contract indigenous population, and extract published regional estimates to calculate a revised hemispheric population estimate with uncertainty ranges.

2.1. Approaches to estimating the indigenous population at European arrival

Historical anthropologists and archaeologists estimate indigenous population numbers at contact by utilizing a range of documentary evidence, including sizes of armies, number of adult males, census data, tribute records, numbers of buildings, depopulation ratios, and historic clerical chronicles such as the number of baptisms and number of deaths in a community (Borah and Cook, 1960, 1969; Dobyns, 1966, 1983). The conversion from such evidence into population estimates has several limitations. Records of the sizes of armies and the sizes of settlements from just after Spanish arrival may be prone to miscounting and exaggeration (Denevan, 1992a) while the conversion from tributes to population numbers requires contentious assumptions to be made (Henige, 1998; Zambardino, 1980). These include the proportion of a population excluded from tributes, average tribute paid per house, number of people per house, conversion from goods into monetary value, spatial homogeneity of population structure and analogies to present day population structures (Borah and Cook, 1960; Sanders, 1976; Sanders et al., 1979).

Colonial census estimates are generally considered more reliable (Denevan, 1992a), but do not capture population levels before European contact (Borah and Cook, 1960). Accepting such censuses as representative of pre-contact populations led to studies from the early and mid-20th century giving very low 1492 CE population estimates (e.g. Kroeber, 1939; Rosenblat, 1954). Some estimate of the population loss on contact is necessary to provide more robust population numbers.

Archaeological data can also be used to estimate pre-contact population size, but again involves several assumptions, such as the number of houses in a settlement that are occupied at one time (Schacht, 1984). But in contrast to historical documents, new archaeological sites are regularly discovered and new and innovative multidisciplinary approaches are being applied to the data, adding new constraints on regional pre-contact population sizes (e.g. Canuto et al., 2018; Goldberg et al., 2016; Liebmann et al., 2016; Storey, 2012). Population densities can be inferred from the number of archaeological sites (Heckenberger et al., 2003), the number of archaeological features such as pottery, charcoal and fertile anthropogenic soils known as Amazonian Dark Earth (ADEs Heckenberger et al., 1999; Meggers, 2001). Expanding on this, the “habitat density method” projects well-studied local population densities to other regions with similar environmental characteristics to calculate the total population under the assumption that population densities in different locations with the same habitat are similar (e.g. Denevan, 1970, 2003; Newson, 1996). Thus, all 1492 CE population estimates require data to be combined with assumptions to arrive at estimates.

Fig. 2. Regions known to have been affected by disease outbreaks by 1600 CE and pre-Columbian land use. Disease outbreak data derives from Dobyns (1993) and Cook (1998). Land use extent is based on high densities of archaeological sites, earthworks and Amazonian Dark Earths occurrence (Clement et al., 2015; De Souza et al., 2018; McMichael et al., 2014; Whitmore and Turner, 1992). The locations of sites and records referred to in the text and later figures are also shown. 

2.2. New pre-Columbian population estimates

We summarize the existing evidence for pre-Columbian populations using seven geographical regions: the Caribbean, Mexico, Central America, the Inca Territory, Amazonia and contiguous forested area, North America and the Rest of the Americas. The Inca Territory at contact encompassed Peru, Bolivia, Ecuador, Colombia, Chile and parts of north-western Argentina; the Rest of Americas is composed of Venezuela, Uruguay, Paraguay and the rest of Argentina. We complied 129 estimates from 82 studies (Caribbean, n = 18; Mexico, n = 17; Central America, n = 23; Inca Territory, n = 26; Amazonia, n = 20; North America, n = 9; Rest of Americas, n = 6; total hemisphere, n = 10; Table 1). Below we discuss the range of estimates for each region and use them to calculate a total population estimate of the Americas in 1492 CE based on all existing data available at the time of this review.

Caribbean. The first contact between Europeans and Amerindians occurred when Columbus arrived in 1492 CE on the Caribbean island of Hispaniola (what is now Haiti and the Dominican Republic). The primary source for most modern estimates of the contact population is a contemporary eyewitness report by the Dominican friar Bartolomé de las Casas who reported a Hispaniola population of 4 million at the time of contact (Denevan, 1992a). However, studies based on this same report range from 60,000 that neglects contemporaneous reports of post-contact deaths (Verlinden, 1973, in Henige, 1978), to acknowledging some degree of depopulation with initial populations estimated at between 100,000 (Amiama, 1959; Rosenblat, 1976) and 8 million (Cook and Borah, 1971, Table S1).

The 8 million estimate has drawn criticism for the worker-to-population ratio used, the assumption of a logarithmic population decline during 1492–1496 CE, and the inclusion of a controversial tribute count from 1496 CE (Henige, 1978). Most estimates are between 300,000 and 500,000 people in the Caribbean before European contact (Córdova, 1968; Dobyns, 1966; Morison, 1948; Moya Pons, 1979; Williams, 1970).

Mexico. Europeans arrived in what is now Mexico in 1519 CE. Yet, the first comprehensive census only took place in 1568 CE, and tribute records are only available as documentary evidence from the late 1540s (Cook and Borah, 1960; Whitmore, 1991). For central Mexico (the most populous region in Mexico) a population of 25.3 million in 1519 CE has been estimated from tribute records (Borah and Cook, 1969), which would make it one of the most populous regions in the world at the time. Zambardino (1980) highlights the uncertainties in Borah and Cook's approach and arrived at a population between 2.2 and 28 million. Dobyns (1966, 1983) suggests the highest numbers, up to 52 million for central Mexico, based on an extrapolation of depopulation ratios from the Valley of Mexico. These values are higher than some estimates for all of Mexico. For the other region with a substantial pre-Columbian population, the Yucatan peninsula, estimates range between 2.3 million (historic documents, Lange, 1971) and 13 million (extrapolation from number of houses, Morley, 1968). Considering all of Mexico, the lowest estimates, which either outright reject (Rosenblat, 1954) or question the accuracy (Sanders, 1972) of the early tribute records, are between 4.5 and 6 million. Intermediate estimates are ∼16 million, based on a linear extrapolation from results of a modelling study incorporating a combination of population, agricultural and epidemiological models for the Valley of Mexico (Fig. 2, near Valle de Mezquital, Whitmore, 1991) and 17.2 million as a best-estimate based on a synthesis of previous estimates by (Denevan, 1992a). Pre-contact population estimates for central Mexico and Yucatan combined, which is considered representative for all of Mexico, range from less than 3 million to over 52 million with many at around 20 million (Table S1).

North America. Europeans began to colonize North America (defined here as the United States of America and Canada) after Central and South America, thus regional and continent wide estimates are largely based on archaeological evidence, tribe-by-tribe counts and environmental carrying capacities (Milner and Chaplin, 2010, see Table S1). The lower range of population estimates for North America lies between 900,000 and 2.4 million, based on tribe-by-tribe counts for the period 1600 CE to mid-1800 CE (Kroeber, 1939; Ubelaker, 1976, 2006). The highest estimate of 18 million, established from analysing environmental carrying capacities (Dobyns, 1983), has been criticized for its assumptions on food acquisition strategies (Milner and Chaplin, 2010). More recent estimates derived from geospatial interpolation of archaeological sites range between 2.8 million and 5.7 million (Milner and Chaplin, 2010). These intermediate figures are supported by a recent comprehensive regional-scale archaeological study (Liebmann et al., 2016).

Table 1. Population and land use at 1500 CE and 1600 CE in P08 (Pongratz et al., 2008a), HYDE 3.1 (Klein Goldewijk et al., 2010), KK10 (Kaplan et al., 2011), and this study. Also shown are their implied net global carbon uptakes as published in Pongratz et al. (2011) (for P08) and Kaplan et al. (2011) (for KK10 and HYDE 3.1) and the calculated net global carbon uptake from this study.

	P08	HYDE 3.1	KK10	This study (IQR)
Population at 1500 CE (million)	41.1	41.2	60	60.5 (44.8–78.2)
Land use per capita (ha per capita)	0.18	0.67	6.25	1.04 (0.98–1.11)
Land use area at 1500 CE (million ha)	7.5	27.7	372	61.9 (43.3–87.1)
Depopulation (%)	65%	76%	90%	90%
Population at 1600 CE (million)	14.2	9.7	6	6.1 (4.5–7.8)
Land use area at 1600 CE (million ha)	4.9	8.7	123	6.1 (4.8–7.4)
Land use change 1500–1600 CE	4	−6.9	−249.9	−55.8 (−38.5–79.7)
Net global carbon uptake (Pg C)	0.009	<0 .1="" td="">	40	7.4 (4.9–10.8)