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Eriksson et al. 10.1073/pnas.1209494109 SI Text Net primary productivity (NPP) was estimated from mean Climate and Net Primary Productivity Reconstructions. We used the annual temperature and total annual precipitation (interpolated HadCM3 model to build a detailed reconstruction of worldwide over a 1° grid from the predictions by the climate model) using climate for the last 120 ky. HadCM3 is a general circulation model the Miami model shown in the work by Leith (16) and described consisting of a coupled atmospheric, ocean, and sea ice model in the work by Adams et al. (17). This approach takes the min- (1, 2). The resolution of the atmospheric model is 2.5° latitude imum of the temperature- and precipitation-limited rates of NPP by 3.75° longitude by 19 unequally spaced levels in the vertical. as the predicted annual NPP. The two limiting rates are calculated The resolution of the ocean is 1.25° by 1.25°, with 20 unequally independently as simple empirical functions of the appropriate spaced layers in the ocean extending to a depth of 5,200 m. The climate variable. The temperature function describes a sigmoidal model contains a range of parameterizations, including a detailed increase in NPP with temperature, with the strongest increase radiation scheme that can represent the effects of minor trace between 10 °C and 25 °C. The precipitation function describes an gases (3). The land surface scheme includes the representation asymptotic increase in NPP with precipitation, with positive NPP of the freezing and melting of soil moisture, and terrestrial evap- at all nonzero precipitation values. The model does not treat oration includes the dependence of stomatal resistance on tem- seasonality explicitly or the effects of CO2, humidity, light capture, perature, vapor pressure, and CO2 concentration (4). The ocean or plant and soil types, but it does provide a simple estimate of model uses the Gent–McWilliams mixing scheme (5). The sea NPP based on observations; hence, it is a good first-order charac- ice model uses a thermodynamic scheme and contains parame- terization of the major climatic controls on ecosystem productivity. terizations of ice drift and leads (6). In this version of the model, interactive vegetation is not included. Notes on Fossil and Archaeological Evidence for Anatomically Modern Multiple snapshot simulations covering the last 120,000 y have Human Colonization Outside of Africa. Arrival dates for anatomi- been performed with HadCM3. The boundary conditions and setup cally modern humans (AMHs) in different regions around the of the original set of simulations have been previously documented world were used to compare fossil and archaeological evidence in detail in ref. 7. The snapshots were done at intervals of every 1 ky with predictions from the model. We summarize the current state from the preindustrial (PI) to the last glacial maximum (LGM; 21 of knowledge of human arrival in different regions in Fig. S7 and ky B.P.), every 2 ky from LGM to 80 ky B.P., and every 4 ky from Tables S1 and S2. Although accurately dated and taxonomically 80 to 120 ky B.P. Boundary conditions are variable between diagnostic human remains are the only unequivocal evidence of snapshots but constant for each simulation. Orbital parameters are the arrival of AMHs in a region, artifacts in the same sites are taken from the work by Berger and Loutre (8). Atmospheric often used to support modern human settlement preceding the concentrations of CO2 were taken from the works by Petit et al. (9) date of the fossils. Niah artifacts, for example, are dated to at and Loulergue et al. (10), and CH4,andN2O were taken from least 46 ky B.P. (18), whereas human occupation at Lake Mungo European Project for Ice Coring inAntarctica(EPICA)(11).All has well-supported dates going back to 50–46 ky B.P. (19). Al- ice-core data were on the EDC3 timescale (12). though Lake Mungo is the only Australian site with human re- The PI to LGM (21 ky B.P.) snapshots use the ICE-5G ice- mains older than 40 ky B.P., archaeological remains from several sheet reconstructions in the work by Peltier (13) as described in other sites confirm human settlements in different Australian ref. 7. The prescription of ice-sheet evolution from LGM to 120 – – ∼ ky B.P. differs slightly from the original simulations. The pre- regions as old as 44 48 ky B.P. (20 22). Older dates of 60 ky B.P. vious study (7) assumed that, during glaciations, the area of the have been suggested for sites of Nauwalabila and Malakunanja continents covered by ice remains similar to the LGM coverage in Northern , but they have been criticized on the basis and ice thickness rises synchronously with d18O [the SPECMAP of possible bioturbation (23, 24). 18 In the , signs of human occupation in both North and record of d O history in the work by Martinson et al. (14) was ∼ used to constrain the evolution of the volume of land ice]. South America by 14 ky B.P. are suggested by several sites that However, this assumption results in unrealistically large extents do not include fossil remains (Table S2). fi of Northern Hemisphere ice sheets during the initial glaciation. In Eurasia, it is more dif cult to use archaeological evidence to fi To attempt to resolve this problem, another set of snapshot sim- infer the arrival of AMHs in speci c regions because of the ulations was performed, in which the ice extent and height pro- presence of archaic hominin species that could, in principle, be ducing a particular ice volume for PI to LGM were mapped onto the makers of artifacts not directly associated with modern human similar ice volumes for LGM to 120 ky B.P. as given by the remains. SPECMAP dataset [i.e., the total volume of ice prescribed in Recently reported skeletal remains at (South the simulations in the work by Singarayer and Valdes (7) is the ) have been suggested as evidence of AMH settlement in same used here, but the evolution of ice extent and height dif- East Asia at least 100 ky B.P. (25). However, the remains exhibit fers]. The ice sheets used in these simulations are closer in areal a mosaic of archaic and derived features, which leaves doubt evolution to those ice sheets derived using ice-sheet models (15). regarding their genuine taxonomic status (26, 27). Other fossil The initial conditions for the snapshot simulations were taken remains of AMHs in China have been associated with dates from the end of each of the simulations in the work by Singarayer older that 50 ky B.P. [for example, the Liujiang remains in and Valdes (7). The simulations were spun up to adjust to the Southern China >68 ky B.P. (28)], but the dates are considered ice-sheet boundary conditions for 470 y. The climate means problematic because of uncertainty in their stratigraphic context described here are averages of years 470–500. (ref. 29, p. 620).

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Eriksson et al. www.pnas.org/cgi/content/short/1209494109 1of7 3. Edwards JM, Slingo A (1996) Studies with a flexible new radiation code. 1. Choosing 17. Adams B, White A, Lenton TM (2004) An analysis of some diverse approaches to a configuration for a large-scale model. Q J Roy Astron Soc 122:689–719. modelling terrestrial net primary productivity. Ecol Modell 177:353–391. 4. Cox PM, et al. (1999) The impact of new land surface physics on the GCM simulation of 18. Barker G, et al. (2007) The ‘human revolution’ in lowland tropical Southeast Asia: The climate and climate sensitivity. Clim Dyn 15:183–203. antiquity and behavior of anatomically modern humans at Niah Cave (Sarawak, 5. Gent PR, McWilliams JC (1990) Isopycnal mixing in ocean circulation models. J Phys Borneo). J Hum Evol 52:243–261. Oceanogr 20:150–155. 19. Bowler JM, et al. (2003) New ages for human occupation and climatic change at Lake 6. Cattle H, Crossley J (1995) Modeling arctic climate change. Philos Transact A Math Mungo, Australia. Nature 421:837–840. Phys Eng Sci 352:201–213. 20. Fifield LK, et al. (2001) Radiocarbon dating of the human occupation of Australia 7. Singarayer JS, Valdes PJ (2010) High-latitude climate sensitivity to ice-sheet forcing prior to 40 ka BP: Successes and pitfalls. Radiocarbon 43:1139–1145. over the last 120 kyr. Quat Sci Rev 29:43–55. 21. Gillespie R (2002) Dating the first Australians. Radiocarbon 44:455–472. 8. Berger A, Loutre MF (1991) Insolation values for the climate of the last 10 million 22. O’Connell JF, Allen J (2004) Dating the colonization of Sahul (Pleistocene Australia- years. Quat Sci Rev 10:297–317. New Guinea): A review of recent research. J Archaeol Sci 31:835–853. 9. Petit JR, et al. (1999) Climate and atmospheric history of the past 420,000 years from 23. O’Connell JF, Allen J (1998) When did humans first arrive in greater Australia and why the Vostok ice core, Antarctica. Nature 399:429–436. is it important to know? Evol Anthropol 6:132–146. 10. Loulergue L, et al. (2008) Orbital and millennial-scale features of atmospheric CH4 24. Roberts RG (1997) Luminescence dating in archaeology: From origins to optical. over the past 800,000 years. Nature 453:383–386. Radiat Meas 27:819–892. 11. Spahni R, et al. (2005) Atmospheric methane and nitrous oxide of the Late Pleistocene 25. Liu W, et al. (2010) Human remains from Zhirendong, South China, and modern from Antarctic ice cores. Science 310:1317–1321. human emergence in East Asia. Proc Natl Acad Sci USA 107:19201–19206. 12. Parrenin F, et al. (2007) The EDC3 chronology for the EPICA dome C ice core. Clim Past 26. Dennell R (2010) Palaeoanthropology: Early Homo sapiens in China. Nature 468: 3:485–497. 512–513. 13. Peltier WR (2004) Global glacial isostasy and the surface of the ice-age earth: The ice- 27. Kaifu Y, Fujita M (2012) Fossil record of early modern humans in East Asia. Quat Int 5G (VM2) model and grace. Annu Rev Earth Planet Sci 32:111–149. 248:2–11. 14. Martinson DG, et al. (1987) Age dating and the orbital theory of the ice ages—development 28. Shen G, et al. (2002) U-Series dating of Liujiang hominid site in Guangxi, Southern of a high-resolution 0 to 300,000-year chronostatigraphy. Quat Res 27:1–29. China. J Hum Evol 43:817–829. 15. Zweck C, Huybrechts P (2005) Modeling of the northern hemisphere ice sheets during the 29. Klein RG (2009) The Human Career: Human Biological and Cultural Origins (Univ of last glacial cycle and glaciological sensitivity. J Geophys Res Atmos, 10.1029/2004JD005489. Chicago Press, Chicago). 16. Leith H (1975) Modeling the primary production on the world. Primary Production of the Biosphere, eds Leith H, Whittaker R (Springer, New York).

Fig. S1. Schematic representation of the approach used to estimate the effect of past climate on human demography through time and space.

Eriksson et al. www.pnas.org/cgi/content/short/1209494109 2of7 Fig. S2. Map showing the locations of the populations in the HGDP-CEPH panel.

Fig. S3. Schematic representation of the demographic model on hexagonal lattice. (A) An initial deme is seeded with cK0 individuals (representing a hypo- thetical ancestral population) at time Tstart.(B) This initial deme grows at rate r until it reaches carrying capacity K, at which point it sends out cK colonists to each neighboring deme. (C) Neighboring demes exchange mNmin migrants (where Nmin is the smaller population size of the two cells), whereas each deme grows at rate r until it reaches its carrying capacity K.(D) After a deme reaches carrying capacity, it is able to send cK colonists to any neighboring unoccupied deme, and the expansion continues. Note that, for the purpose of illustrating the model, all demes are shown here as having the same carrying capacity.

Eriksson et al. www.pnas.org/cgi/content/short/1209494109 3of7 Fig. S4. Posterior distributions of the model parameters estimated using approximate Bayesian computation–generalized linear model (GLM). The model selected for a relatively old expansion time Tstart (A; thousands of years ago) from a relatively small initial population size K0 in sub-Saharan Africa (B). The maximum carrying capacity Kmax was relatively large (C), with comparatively small number of individuals colonizing new demes cKmax (D) and migrating between adjacent populations mKmax (E). Populations in colonized demes grew rapidly (F;larger). The lower NPP threshold, NPPlow (below which human persistence is not possible), is sharply defined (G); in contrast, the upper threshold, NPPhigh (above which the carrying capacity is equal to Kmax), can take a broad range of values without affecting the model fit(H).

Eriksson et al. www.pnas.org/cgi/content/short/1209494109 4of7 Fig. S5. Map showing the locations of modern hunter–gatherers that were used in Fig. 1.

NPP2 ) t ( NPP Interpolated

NPP 1 t t 1 Time t 2

Fig. S6. Interpolation function for NPP between two snapshots (t1 and t2).

Eriksson et al. www.pnas.org/cgi/content/short/1209494109 5of7 Fig. S7. Key dates for early presence of AMH outside Africa. Dates associated with human remains are bold; other dates refer to archaeological evidence of occupation. The shaded region in North America marks the extent of the Clovis technocomplex.

Table S1. Widely supported dates for early arrival of AMHs in Eurasia and Sahul Remains Location Latitude Longitude Minimum date Refs.

Skhul and Qafzeh ca. 32°40′ N ca. 35° E 130–90 ky B.P. 1, 2 North China 39°39′ N 115°52′ E 42–39 ky B.P. 3 Niah Cave 3°49′ N 113°47′ E 45–40 ky B.P. (>46 kya, archaeological)4 Yamashita-Cho Cave Okinawa, 26°12′ N 127°40′ E 33–32 ky B.P. 5 Bobongara Point, Huon peninsula New Guinea ca. 6° 25′ S ca. 147° 30′ E >44 ky B.P. (archaeological) 6 Devil’s Lair Southwest Australia 30°9′ S 115°4′ E44–46 ky B.P. (archaeological) 6, 7 Lake Mungo Southeast Australia ca. 33°45′ S ca. 143°08′ E 42–38 ky B.P. (50-46 kya, archaeological)8 40°09′ N 17°57′ E 45–43 ky B.P. 9 50°28′ N 3°30′ W 44–41 ky B.P. 10

Dates in bold refer to AMH skeletal evidence; other dates refer to archaeological evidence.

1. Grün R, et al. (2005) U-series and ESR analyses of bones and teeth relating to the human burials from Skhul. J Hum Evol 49:316–334. 2. Valladas, et al. (1988) Thermoluminiscence dating of Mousterian “Proto-Cro-Magnon” remains from Israel and the origin of modern man. Nature 331:614–616. 3. Shang H, et al. (2007) An early modern human from Tianyuan Cave, , China. Proc Natl Acad Sci USA 104:6573–6578. 4. Barker G, et al. (2007) The ‘human revolution’ in lowland tropical Southeast Asia: The antiquity and behavior of anatomically modern humans at Niah Cave (Sarawak, Borneo). J Hum Evol 52:243–261. 5. Takamiya H, et al. (1975) Excavation report of Yamashita-Cho cave site Naha-Shi Okinawa. J Ant Soc Nippon 84:125–130. 6. O’Connell JF, Allen J (2004) Dating the colonization of Sahul (Pleistocene Australia-New Guinea): A review of recent research. J Archaeol Sci 31:835–853. 7. Fifield L, et al. (2001) Radiocarbon dating of the human occupation of Australia prior to 40 ka BP—Successes and pitfalls. Radiocarbon 43:1139–1145. 8. Bowler JM, et al. (2003) New ages for human occupation and climatic change at Lake Mungo, Australia. Nature 421:837–840. 9. Benazzi S, et al. (2011) Early dispersal of modern humans in Europe and implications for Neanderthal behaviour. Nature 479:525–528. 10. Higham T, et al. (2011) The earliest evidence for anatomically modern humans in northwestern Europe. Nature 479:521–524.

Eriksson et al. www.pnas.org/cgi/content/short/1209494109 6of7 Table S2. Overview of key evidence for first arrival of AMH in the Americas Remains Location Latitude Longitude Minimum date Refs.

Paisley Caves Oregon ca. 42°47′ N ca. 120°40′ W 14.5–14 ky B.P. (human DNA 1, 2 extracted from coprolites) 41°30′ S 73°06′ W14.6–14.2 ky B.P. (archaeological) 3, 4 Clovis technocomplex North America ——13 ky B.P. 5 Buttermilk Creek (Friedkin site) Texas 30°57′ N 97°32′ W15.5–13.2 ky B.P. (archaeological) 6 Meadowcroft Rockshelter Pennsylvania 40°17′ N 80°29′ W 14.5v14 ky B.P. (archaeological) 7, 8

Dates in bold refer to AMH remains; other dates refer to archaeological evidence associated with AMH.

1. Gilbert MTP, et al. (2008) DNA from Pre-Clovis Human Coprolites in Oregon, North America. Science 320:786–789. 2. Poinar H, et al. (2009) Comment on “DNA from Pre-Clovis Human Coprolites in Oregon, North America.” Science 325:148. 3. Dillehay TD (1997) Monte Verde, a Late Pleistocene Settlement in Chile (Smithsonian Institution Press, Washington, DC), Vol 2. 4. Dillehay TD, et al. (2008) Monte Verde: Seaweed, food, medicine, and the peopling of South America. Science 320:784–786. 5. Waters MR, Stafford TW (2007) Redefining the age of Clovis: Implications for the peopling of the Americas. Science 315:1122–1126. 6. Waters MR, et al. (2011) The and the origins of Clovis at the Debra L. Friedkin site, Texas. Science 331:1599–1603. 7. Adovasio JM, et al. (1990) The Meadowcroft rockshelter radiocarbon chronology 1975–1990. Am Antiq 55:348–354. 8. Adovasio JM, Page J (2002) The First Americans. In Pursuit of Archaeology’s Greatest Mystery (Random House, New York).

Movie S1. Animated reconstruction of a representative scenario with parameter estimates close to the most supported values. The hue of the color represents the carrying capacity; the α-channels gives occupancy by humans (transparent cells are unoccupied; full colors show inhabited cells).

Movie S1

Dataset S1. Within- and between-population time to most recent common ancestor for the HGDP-CEPH populations (in thousands of years ago) as estimated using di- and trinucleotides only

Dataset S1 (XLS)

Eriksson et al. www.pnas.org/cgi/content/short/1209494109 7of7