Video: Climate, Water, and the Evolution of Early Societies: From the Tropical Maya Lowlands to the Arid Puebloan Southwest

The earliest complex societies found in the Western Hemisphere developed under very different environmental conditions. The Maya, for instance, emerged in the tropical lowlands of the Yucatan Peninsula, a region with high seasonal rainfall and rich biodiversity. The Puebloans, in contrast, developed in the semiarid region of what is today Arizona and New Mexico, an area with limited rainfall and biodiversity. Vernon Scarborough will discuss two important archaeological sites from these different ecological and cultural zones—Tikal in Guatemala and the Chaco Canyon in New Mexico—to illustrate how the availability of water and climate influence the evolution of societies and what we can learn from these historical precedents.

Gordon R. Willey Lecture Series recorded 10/18/2016

Vernon L. Scarborough, Distinguished University Research Professor and Charles P. Taft Professor, Department of Anthropology, University of Cincinnati


[00:00:05.34] So good evening, everybody. Welcome. Thanks for coming out on a lovely fall evening. So now for something completely different. My archaeologist, who is a distinguished comparativist and applied anthropologist and a good citizen of the world, not too many people like Vern Scarborough. As Jeff mentioned, he's a distinguished university research professor and a Charles Taft professor in anthropology at the University of Cincinnati.

[00:00:37.71] Before I go further, I'd like to also thank our sponsor, many years ago, a graduate of our PhD program and before that an undergraduate student here. In many ways a mentor to me, he was four years ahead of me in the graduate program at Harvard, Richard Leventhal was the one who donated the funds for the Gordon R. Willey lecture to bring distinguished scholars of Mesoamerica like Vern here to tell us about their research. So Richard apologized that he wasn't going to be able to make it. His class meets tomorrow morning at 9:00, so you can understand he wouldn't be up partying hardy with all of us to celebrate Vern's talk, but he's here in spirit.

[00:01:26.01] Dr. Scarborough's interests are settlement land use, and water management in the context of the archaic state. By looking at ancient engineered water systems and landscapes, he addresses societal sustainability issues from a comparative ecological perspective. To achieve that, he emphasizes cross-disciplinary exchange and international fieldwork.

[00:01:53.03] So he's presently editing a volume called Water and Humanity, a historical overview for UNESCO, a major initiative of their international hydrological program based in Delft. He's also a member of the scientific steering committee with, I hope, integrated history for the future of the people of Earth, an effort of the International Geosphere and Biosphere Program at the Stockholm Resilience Center.

[00:02:25.21] Since 1992, Vern has been co-director of the program for Belize Archeological Project, a large annually, very active research program in Northwestern Belize. His most recent field work focuses on water and the engineered landscape at the great ancient Maya center of Tikal in Guatemala. But he and his University of Cincinnati geographer colleague, the marvelous Nicholas Dunning, also just got another very large NSF grant to apply the information that they learned on that project to a new area in nearby Campeche, Mexico.

[00:03:04.12] So I first became acquainted with Vern's work with his still heavily cited book that he edited with David Wilcox called The Mesoamerican Ballgame, riding on the ball courts of Copan, and it was a great resource, still is. Vernon was telling me the other day he still gets a $15 check in royalties from the University of Arizona, every year like clockwork. It's a great book, published in 1991. Imagine that, 25 years later, enough for a pizza.

[00:03:37.95] And then in 2003, The Flow of Power, tour de force, on the subject of Ancient Water Systems And Landscapes, published by a School of American Research Press in Santa Fe. 2007, another very heavily cited volume, The Political Economy of Ancient Mesoamerica, Transformations During the Formative and Classic Periods, University of New Mexico book that he edited with the redoubtable John Clarke.

[00:04:06.40] So he's published in all sorts of journals as you can imagine, given the interests I've just been mentioning. So all of the big journals in archeology and Mesoamerican archeology, but there are also others like water history. So an interesting title published there was The Non-Hierarchical Development of Complexity in the Semitropics, Water and Cooperation. In American antiquity, Complexity and Sustainability, Perspectives from the Ancient Maya and the Modern Balinese. There's the comparative element.

[00:04:40.18] In 2009, Future of Planet Earth, Seminar Proceedings, impressive. Sponsored by UNESCO. He also wrote the conclusions of a magnificent book on pre-Colombian water management that was co-edited by a member of our audience. Vern is a great colleague to everyone. This is something universally acknowledged, a marvelous friend and as the Yukatec Maya would say, [SPEAKING MAYAN], a true human.

[00:05:12.83] So please join me in welcoming Vern Scarborough.

[00:05:17.36] Well, what do you say after an introduction like that? Well, thank you for being here, and thank you for the invitation, Jeff. Of course, the Fashes-- Barbara and Bill-- for the invitation and being here, it's just a real privilege. I want to acknowledge at the outset what Bill alluded to with regard to my just great colleagues that I have been surrounding me for the better part of 30 years. And being at Cincinnati, Nick Dunning, a geographer, and David Lentz, a biologist, we worked together with regularity.

[00:06:01.35] The work you'll see tonight presented on Chaco Canyon pulls in Steve Plog in Virginia. He's instrumental in any success it may have. And then Liwy Graziaso at Guatemala City, for the work at Tikal. And that's just a brief overview of the many people that have influenced what you'll see this evening. I'm just a conduit really in many ways.

[00:06:24.65] Again, at the outset, I wanted to mention that Harvard has a very long-- it's not long, it's early history of working in the American Southwest and the Maya Lowlands. And what I'll venture to do is try to connect these in a way that maybe hasn't been done in the past using climate as a vehicle.

[00:06:49.52] In that context, we have Kidder, Morally, Bollard, who do have also on that list, Tosser, Shepherd. These were real luminaries that identified the role of archeology in the new world. And they went from the southwest to the Yucatan and back.

[00:07:11.49] The other element I want to get into and just really focus on now is this wet and the dry. And of course, that's set up by those two extremes I just mentioned, but it's a global. And how a dollop of water here or a rainstorm there affects our world view over the long dure is really influential. And I think sometimes we are not aware of that or don't put that in our psyche enough. And their different. When you have a lot of water in one place, you make different kinds of decisions, and I think you'll see that this evening and in the past.

[00:07:50.15] This illustration is just to emphasize. The origins of agriculture, of course, we associate the Near East, certainly very dry, semi-arid for sure. And the kinds of plants and animals that were domesticated were naturally concentrated. So you had large, long, or sizable, maybe even vast fields of wild grasses that consciously and unconsciously humans could manipulate if they were predisposed in terms of their biology or genome.

[00:08:26.49] And that's true of animals too. You think of cattle and goats and sheep, these are herd animals. And again, if they have a constitution that allows them to be domesticated, it can happen. But they are gregarious animals and they're sizable groups. And that model is very different when you move into the tropics. That's not a luxury really available to people, even though we're social creatures and would gravitate towards research concentrations that are there and this magnified in if we can leading ultimately to the early state and that kind of concentration.

[00:09:06.74] But tropics have this wonderful diversity of plants and animals that we're all very aware of. Perhaps 40%, maybe max of the surface to the Earth, at least the land surface of the Earth, is part of this semi-tropical build. Within that reach, there are probably 60% of the diversity on this planet, maybe more.

[00:09:32.10] And we could end it there, that's interesting, but it turns out that it's a very different distribution of plants and animals. They don't naturally congregate or concentrate. So it's a lot of work for humans to pull us together in terms of concentrations that we assume will lead us forward if we're going into levels of complexity that we associate with the early state.

[00:09:56.76] You have a jaguar here, a kindred maybe several kilometers away. You have a mahogany over here a few meters away, maybe further, another mahogany. So the ability to concentrate these animals and plants is a different realm, and in that context, the wet in the dry, humans see the world differently. Their infrastructures are differently, and I do think it affects your world view differently.

[00:10:23.93] Let me see how I advance things here. Oh, this is just to illustrate grains, wheat on your left, Catalhoyuk this great site about 5500 BC and the concentration of people on location on that mound. And then juxtaposed in the tropical setting, being yams where Southeast Asia has been depended upon them, a root crop to accommodate storage. Big problem in tropics that you might well expect. And then the site of Angkor, this marvelous site about 8th to the 12th century, we have a very dispersed settlement pattern, a mimicking that rhythms of this part of the world. Even though there are 3/4 of a million people there at that period time, it was probably the largest pre-industrial site in the world, but not concentrated by our definition of urbanism or the Near East.

[00:11:22.51] Let's see here. Just to summarize, that first slide, basically, and some of the points I hope to run through at the presentation, the dry, concentrated resources, of course. Settlement density. You have these sizable populations concentrated. Canal systems tend to be what is supported in these settings in semi-arid, arid, and good preservation. So storage is a problem, but it's not like it could be as we flip over to the other side with the wet where you have disbursed arrangement, mimicking the rhythms, the biological, the biophysical rhythms of this setting.

[00:12:02.84] Reservoirs seem to be the case holding water. It's semi-tropical. It doesn't rain all the time. And because of that drought-like period, we'll see, particularly in the Mayan area, you want to hold water otherwise you'll lose it. And it's really a different kind of definition to water control and resource control.

[00:12:21.11] And poor preservation. And that's where these guys come in handy. This is manioc, a root crop. And you don't have to take it out of the ground right away. It can go annually two, three years, mature, but it's stored, very different adaptation. That's possible in tropical settings.

[00:12:38.87] That's Tikal in the center field here. And then the flip side, actually, those are sites in the Southwest where you do see this resource concentration in a different way. Storage is much easier in the storage rooms and then canals, that's Snaketown. So the Hohokam really did invest in that kind of reality in that very dry setting.

[00:13:04.82] Both views with this wet and dry, from our vantage point, it's good temperate occupants is marginalized. They're difficult places to make a living from our vantage point. Of course, we're buffered by years of technological advancement. But in the good old days, we're talking about now, and they were livable. They made them livable. And they had to work to do it, of course, but in a different way than we do. They didn't have technological advantages.

[00:13:33.83] We do focus on the arid for the most part in archeology, I mean years, years, years. I think it's a comfort zone, in part. Ease of access to a degree if you're in the Near East, European, of course, Egypt, even along the Indus. But that being the case, there's more to the picture.

[00:13:59.60] Continuing along that theme with regard to the dry, we have the earliest agriculture, as I mentioned, perhaps at a place called Abu Hureyra, but it's one of probably many, say 12,000 years ago. And then with these advances about 5,500 years ago a place called Choga Mami that's close to 5500 BCE. And that is where we get this canalization work, the change in the landscape, moving water into zones that were wasteland. And basically, desert is a bloom, and that can affect population right away and resorts concentration right away.

[00:14:41.33] The fellow that really pushed a lot of this, and not the ecological component that I've emphasized here today, was a fellow called Wittfogel. And under his umbrella of looking for lawful statements that was something anthropology was very keen on doing back in the '50s and '40s and '60s, he came up with a rather dense and some turgid explanation for triggering social organization at this most complex level, the early state. And he thought water was what dictated it and particularly canalization efforts and primarily in semi-arid settings.

[00:15:24.71] He worked on that in China, but he spread this view across the Earth explaining the archaic state. And these are some of the attributes that he was big on. And the one with regard to bureaucracies led to the kind of social divisioning that led to the social complexity and structure of the state, bureaucracies, in part, to monitor to move a finite resource, water, and fundamental resource to folks elsewhere. And timing that and controlling it took on another level of social order.

[00:16:04.16] Also, and I think it's of interest and many times associated with these early states in these very dry settings, they have these investments in water. They're very public and very visible. It's a way of symbolically and politically emphasizing control.

[00:16:23.42] So beyond the immediacy of the water itself, if you're able and you're in a controlling position, and can basically, conspicuously consume it given the evaporation rates and given a limitation of the resource, you are showing a bit of control of the resource. And these are some of the features. This Grenaa, Mohenjo Daro, those great aqueducts from Italy to Spain.

[00:16:55.08] So why the Southwest? I mean, wouldn't I be best advised to look at the Near East or some other place to try to get at this notion of dry when we're talking about state? Because we don't have state, at lease in the same way that we've defined it elsewhere in the world and at levels of social complexity in the US Southwest.

[00:17:20.40] The extreme aridity, I think, is one of the principle components for the difficulty to push it, for folks to have developed much the way they did in Highland, Mexico or the Maya or Peru. But they're very complex and very clever, and they pushed it about as far as you could given the resources, particularly limitations of water, that they were able to. And clearly the whole calm were magnificent in pushing it that way.

[00:17:55.15] That problem has limited what we can do in the Southwest in terms of these models for the archaic state. However, I might suggest to those that do work in that part of the world where you have archaic state, particularly in Near East, that the Halafians, the Sumerians, maybe the early Ubaid periods where we don't have the kind of control. And what really happened there with regard to landscape development might have some lessons from the Southwest.

[00:18:24.39] The beauty of the Southwest is you have dendrochronology, dendroclimatological data. So you can look at things almost hourly. I mean, we're talking yearly by these annual rains. And coordinating that rain flow, and I'm looking at the material culture that's left in its wake, is a marvelous control. And how these environments changed with that kind of control ought to be helpful in looking at other parts of the world that are arid and looking at the trajectory that ultimately comes or is associated with the early state elsewhere.

[00:19:01.19] Our work is looking at Chaco Canyon specifically of late. And we have this meteoric growth of these Puebloan towns there. It's really unusual for the Southwest too, particularly the ancestral Pueblo in Southwest, that Four Corners area.

[00:19:19.45] It's in New Mexico, of course. The heyday is featured there, about 800 to 1130 or so. And then there is a relatively abrupt abandonment. By 1200, the place is pretty much empty. There are a few folks, but not many. Most of them move up into the Four Corners area, Mesa Verde.

[00:19:37.72] The interesting thing about this marvelous period is the size of some of these sites. They're really huge. Pueblo Benito down here has estimates around 600 rooms. And it's built, again, in that modular apartment-like building, concentrated. And you'll see when I look at the tropics, it's a very different model. They did build in stone, but much of the Southwest builds in adobe, clay, not a good idea in the tropics.

[00:20:04.85] So what ends up happening in settings like this is that you can and do build on top of one another. And that's, again, a different worldview, a different way of organizing. And really it's our model, our trajectory out of the Near East that we live today. That is the model.

[00:20:21.94] The tropics are this other world, and we really haven't investigated in the matter that the human trajectory, I think, necessitates. It's continuing like this, very uncertain environment. Rainfall is erratic. When it comes, you've got to be on top of it. And it erodes things rapidly, aggrades things in other locations.

[00:20:45.28] And moving populations around to accommodate that, I think, was one of the principle components for why these folks orchestrated their environment the way they did. They had to have these super families or groups that began to coordinate others to make sure water did get to where it had to go to make an environment workable.

[00:21:04.99] The canyon itself is about 30 kilometers in length, maybe a kilometer and a half wide, but you can have a cloudburst even a kilometer away that won't affect you. It's that erratic nature, and having people on call to move rapidly makes a difference about scheduling and movement.

[00:21:25.77] I might mention that affects world view. And the way you can center people and provide some kind of certainty in a very uncertain landscape is ritual and ideology and politics. And you can provide that to people, then you can begin doing the kinds of things with regard to these great houses that they call them that you can't in other contexts.

[00:21:51.46] Chaco Canyon. This is just the geology of it, if you will, geomorphology. Unique in many ways. This panel on here to your right just shows this cutting aggrading period's base level changing. That is, it changes the flow through time, and this can be done climatically with more or less rain, or can be induced anthropogenically by humans having unintended consequences in their environment.

[00:22:19.43] Both those things work in tandem make it very difficult to tease out, which is causal, which is really the case today with our questions about climate change. But this is a neat model to try to unravel that. That year-to-year change could really affect one's world view. And I'm of the opinion that looking for that kind of certainty was what kicked in the infrastructure, but also a new way of looking at things.

[00:22:51.25] Fred Eggan, a rather prominent ethnographer, once said that the Puebloan population currently was the most ritualized society in the world. Wow. This is a very smart man. Now, if that were the case, it may a bit of exaggeration, they're doing something to try to figure out how to live in this environment.

[00:23:17.76] Our recent work, associated, these are the kind of things we do as archaeologists, and many of you are quite empathetic, I think. And we're not working at the great houses. We're working in the fields, literally, away from what was the community back then, trying to figure out how they fed themselves, how they organized in that space, and how it may have affected their social organization by extension.

[00:23:42.04] Dating as a real troublesome area for any archaeologist and particularly where we're working, one of the things that we found is something called optical stimulated luminescence, dating sand. Because the incidence of trash debris, midden debris, charcoal is really slight in these settings, and it's probably moved pretty far away from its source too. So it's troublesome.

[00:24:07.72] That said, we have about 30 to 40 dates now to help us coordinate this ebb and flow of the environment, that is the aggradation and erosional rates as they come and go. And we're trying to coordinate that with our dendrochronological information and in turn, look at when the heyday of that is the architectural pivot points that they induced for their own social organization. All that trying to get out what's generated by humans and what's generated by the environment and teasing that through. It's tricky, and I don't know if we'll ever get there in a convincing manner, but we're trying.

[00:24:50.52] A couple of ways of looking at the Southwest, and particularly Chaco Canyon, it's very tail, as it moves into this other wash called the Escovada right here. This is Chaco Canyon, the rift may be, I don't know, probably a kilometer here. And then the present incised course, the Chaco Wash that cuts through the canyon was responsible for its incision from the Cretaceous or something, a long time ago.

[00:25:17.91] But what we're really interested in is a theory that some folks, Gordon Vivian and Eric Force, and other, that at one point, this dune, which they suggest was there when the Puebloans were there, so contemporaneous with these great houses. And I think there's one you may be able to see, Penasco Blanco here. That's from the aerial. This is called LIDAR. It's a very useful imagery that allows you to get very settled topographic information from the surface of where of it's being photographed or taken.

[00:25:51.32] One of the things, this is about a 150, 200 meter of dune that projects out from a mesa that's solid rock and then probably 30 make it 50 meters wide, maybe 9 meters high. And these dunes do migrate, so we're not sure. Our OSL dates suggest it's rather recent.

[00:26:14.63] If that's the case, the notion of a dune hypothesis where this was projecting out during the fluorescence of the Pueblo and great houses could have been closed off. That's the scenario. And that they would have closed off and then produced a bit of a lake in its wake, back behind it. That would be really fortunate for them if that was played out. We don't have clear evidence for it right now.

[00:26:41.48] We're working at it because all these lines, alignments are cores we take. I showed an earlier slide of one of these things, trying to figure out-- it goes down about three or four meters and brings out this, if you will, a biopsy of Mother Earth. And we correlate them with excavations to better understand what's going on. That's pending, something we're working on. I do think we'll get some kind of resolution on that relatively soon.

[00:27:08.15] The other element that we're finding at the same area is looking at watersheds. What would be the source for any [? camp ?] canals that we might discover feeding these fields? They could come off these ringcones and these are all catchments, these different colors are where water is being trained just off the surface naturally into the same area you just saw. And this is the incised wash today. The dune is like so.

[00:27:38.57] And the idea here is, is it possible that's not just coming off the ring cones haphazardly with every cloudburst or even being diverted from the main course of the wash up into this area? Or is it possible the Escovada itself is a completely different drainage, a completely different watershed being routed around? That's a hypothesis we're playing with, introduced about 40 years ago by Gordon Vivian, the first director at the monument, Chaco canyon.

[00:28:11.57] And if you look really hard, you can of see a scar like so. And of course, we have this dune to contend with which would be later in our scenario bringing water right in to a zone right here. I'm going to show you some canals that we've excavated. That's what they look like in reality, but we clean them up, Nick Dunning.

[00:28:34.36] The holes are where you have to take this canister to remove the soot, the sand to date the sediments there, and they bracket the canals. That discoloration or clay lenses, those clay lenses are ancient canals, and we're curious about where that came from.

[00:28:53.42] There is what Nick Dunning who runs this. He's a sedimentology, really great. I mentioned it at the outset. And he's been able to reconstruct what that is about with regard to our sediment history. The really interesting thing we're getting to now is there's a technique called the x-ray fluorescence. And it's a wonderful technique, and it allows you to look at the elemental constitution of clays.

[00:29:22.22] And so what we did is, we collected from all of these sources, potentially, the ring cones, I mentioned these are basically royal heads, the watersheds, along the Escovada, the top there, along the Chaco Wash itself and try to tie them back to the same fingerprint associated with these clays. Where are they coming from?

[00:29:42.11] Right now it's up in the air. We're getting close. We do know that some of the clays are coming from the Chaco Wash. So somehow they routed that lower-lying stream into that area. Today it's uphill, and it would be very difficult to do. So again, it suggests a fair amount of meandering.

[00:30:05.91] The incision, if you visit Chaco Canyon there and you see that deeply incised Chaco Wash, it's something that's only happened in the last 100 years. So we know there's a lot of change overall.

[00:30:18.43] That's the dry. We'll end it there. The wet, also marginal for us in this room. But what happen there? This is Tikal, of course, that most of you have visited. And these are some raised fields that I worked in years ago. These are elevated almost like Chinampas, the floating gardens of Highland, Mexico in proximity to the area I work in Belize with Red Valdez, also a very close colleague.

[00:30:47.00] And I want to make sure you understand that my argument isn't dichotomous. It's not wet and dry. It's a complicated picture, of course. It's a continuum and not linear. The shot down below are the Marsh Arabs just north of Basra in present-day Iraq.

[00:31:14.32] And they're pretty much gone now, thanks to Saddam and then since government problems. But it indicates that the Sinagas Swamps and swamp people, if you will, were around for a long time even in dry places. So wetlands may have been tapped early on, even for the origins of agriculture, very high water table. We'll see.

[00:31:40.39] Wetlands suggest a couple of things, and they're more than a couple there-- a different order of planning. I'm juxtaposing us with our friend, Wittfogel, and those dry settings. And I'm not going to belabor this just because of time, but these attributes seem to be something that from my purview are repeated globally in various wetland settings where you have humans managing them and where you begin to have these attempt at the concentration of resources.

[00:32:10.70] One thing I will emphasize is the still water versus the flow system. This means canal systems versus the quiet, slow movement of water in these wetlands. It's a very different kind of control. What you have in those settings, of course, is investment in maintenance big time. It's unlike the planning association to a degree when you find canal systems laid out for sometimes kilometers.

[00:32:41.50] These acquire because the soil is so saturated, weekly attention to make sure they're properly mucked, you get the matrix on top of the platform to grow your crops. I think you've heard that story. Tend to be centralized as communities would be in this model that's mimicking to a degree the biological rhythms all around you, very different definition.

[00:33:05.74] Low-density urbanism, we'll see more of that with the Maya. And then rural settings just don't quit. People continue to occupy the interstices between sizable urban nodes. I mean, there's more people in a node as you might well expect, but it doesn't drop off markedly, whereas it can in a place like Teotihuacan, for instance, did.

[00:33:29.77] In the village-level order definition of community, I'm not going to have time to really convey that. Maybe later on we'll talk about "tragedy of commons" because I do think there's an interesting association with canal people versus wetlands people.

[00:33:47.31] Maya Lowlands, the size of UK, just the geography of it, extremely long lived. The mire or the Maya. Amazing thought. 1,500 years maybe better. Well, better. They're there today. And they maintain still that culture identity of the Maya. That's pretty unusual when you look at the Near East. I mean, we're talking about just a few hundred years in many cases. The Persian, the Medes, the Arabs. You just name it. Babylonians. That's not the case with the staying power of this group.

[00:34:22.15] 90% of the rainfall, seven to eight minutes. So it's truly a semi-tropical setting, and that affects how you live because that drought period is a problem. And then these great bajos, these lowland areas, 40% maybe more in certain areas, for sure, are just inundated for about seven months, and then the rest of the time they're very dry.

[00:34:47.11] The Maya and this group, in fact, it's a new world myth or world view that water mountains for the Zuni clear down to northern Chile, the notion that water is somehow captured and held in mountains. And caves are particularly attractive areas because they have seeps and springs, and it just confirms the fact that you have this reservoir inside a mountain. And indigenous people today believe this, many of them. There's pilgrimages throughout Highland, Mexico to these places. And there's a very nice chapter, actually in the UNESCO book that Bill was mentioning to you that looks at this work.

[00:35:33.21] The interesting thing is that the Maya took that worldview and made it functional. No other group really has done that in the new world that I'm aware of to this, the same extent. And the way they did it they started off with something I'm referring to in the classic and the pre-classic period, which is I'd say about 400 to maybe 200 CE, the current era. So 600 period something like that at that transitional point, they went into those bajos, those low-lying areas and they began to modify them because the water was elevated, but they needed to hold water for the year round.

[00:36:11.85] And the way they did that was to begin to dig into the margins of those bajos or maybe a little bit further upslope and produce matrix, material that would then be used to build their centers. So what goes down goes up. And I joke with many of my colleagues that these marvelous architectural features are an afterthoughts. What they were really after those water containers, the quarry. And you had to put the fill somewhere.

[00:36:43.23] Well, anyway, these areas you see in this schematic were being dug deeper to hold more water and to a degree effect the surface area for evaporation and held water for extended periods of time. With time, the late-great classic folks were extremely successful in this landscape. And that's apparent when you look at the iconography, you look at the architecture, they were good at what they did, but some things happened.

[00:37:15.19] One, we have evidence now for a drought. That was pretty serious. And drought affects vegetation. It can affect then the routing of the vegetation, which in turn affects erosion. And that coupled with the higher density of people that were successful in these settings, they began to incur erosion with some degree of concern. And it began to infill their depressions where they just opened them up. And it became an endless battle near as we can tell.

[00:37:46.53] Eventually the system is troubled. It could have been the end of the Maya, but they were very clever, very clever. And they had already colonized the upper reaches of these depressions, and they began then to utilize the more elevated settings and using the same model. But now they are inventing source, water mountains.

[00:38:10.71] They're capturing the water by digging out quarry scars and damming up elevated arroyo settings, holding water in those locations using the fill from expanding those depressions, those quarry sites, to build their pyramids. The areas on the summit, the ridge itself where this city is being developed, are paved. Again, it's a karstic environment. If you don't, you're going to have water loss for sure. It's pervious. It's porous. You can lose water on that surface getting washed up.

[00:38:45.18] So you pave it, you cant it, and water is directed into the corries that you're building your pyramids. Very clever. Very active. If this is a passive system, this is very active. If this tends to be less centralized, this tends to be more so.

[00:38:59.37] Resource concentration is their interest, not only in terms of the water supply, but the human supply. You're bringing people together, organizing in a different way, and I would suggest that water is a big part of the picture. Not entirely. Now, don't get me wrong. I'm not terribly deterministic, but I do think it's part of the landscape effort that's changing the reality.

[00:39:24.27] This is recent work Bill suggested or slightly introduced. This is that schematic or isotopic--

[00:39:36.43] Reconstruction.

[00:39:37.83] Reconstruction-- thank you-- of Tikal and a bird's eye view if you're flying through it. And the blue, of course, the reservoir spaces, and the arrows indicate how water is coming off that surface. In that context, again, this is all paved up here and that convex micro watershed idea water shedding down store down after being opened up by various dams and such during the dry season that fills up incredibly during the wet season.

[00:40:06.72] In fact, in this area, the major catchment zone for the surface, which they carved out, capitalized on, took the natural forms and then accented them, in that area, it's about 62 hectares, if it rains 1,500 millimeters a year, about a million cubic meters of water will collect. Well, can't. It shed. A quarter of it, though, is held in the voluminous reservoirs up here for that dry season follow up.

[00:40:32.43] And by simple gravity flow, they open the sluice gates and out it comes and services the population that rings around this center. The center is pretty much private space in many ways, not that people don't come in there for pilgrimages, markets, all that's going on. Nevertheless, most of the really influential folks are up there, but the supporting population, although it's mixed, are around this concentric zone and then off into the hinterlands.

[00:41:02.01] These are some of the elements. I'll look at them quickly. This reservoir business you'll see in a moment, coffer dams, ancient springs linked to initial colonization, the sands filtration.

[00:41:16.77] Romans probably or did have the market on early definitions of potable water that we all know everything from there line-lead pipes. They didn't suffer from lead poisoning because they had a certain kind of environment very similar to the Maya that coated it with a calcium carbonate. But these guys had sand filtration, we think, which, again, people padding around during market days up here at the summit and you're moving water off the surfaces, then you're going to have a bit of a problem.

[00:41:50.32] You can boil it. No doubt they did with some regularity, but they didn't have the kinds of technologies we have, and putting it through a sand filter had a lot of appeal, and we'll see how that might be argued. Switching stations, it's a very intricate system.

[00:42:08.85] This is just a reconstruction of one of the dams, Palace Dam. Very clever. Again, that's one thing Maya were very good at. That's a gravity dam, meaning it's bulky. It's holding the water back, but it appears to have a series of stacked orifices, sluices that run horizontally one under the other.

[00:42:32.22] And the idea there is if you had a large opening that you had to open up, which would have been very difficult with technology, it could blow the whole thing out. But having a series of small orifices or sluices lined up with some kind of plug you pulled when you're at the surface level, you can reduce it. You can see what the idea is.

[00:42:51.75] That's something only reported elsewhere in the world at this time in Yemen, interesting, about 700 AD. So the Maya were on top of things, and I don't think there were spacemen generating this kind of interaction.

[00:43:11.55] This is another kind of reservoir we found there. There were these bajo-margin swamp, margin reservoirs. And water here in the late pre-classic was coming in in a very slight matter. That's that drought period.

[00:43:27.00] So it looks like they were moving water to maximize capacity. We find, subsequently, it gets complicated even for me, so I'm not going to get into this too much, but you get an idea of the system. During the classic period where we can find more rainfall, this conduit here, this canal is completely filled up with plaster.

[00:43:52.86] Actually, it looks like it's a matrix that they would have used to cement their buildings, and it's completely filled. And the reason they did that is that there was too much water. They were routing water away from this location.

[00:44:07.75] So climates having an effect, and they are coordinating your activities to accommodate it. This other little schematic here, this profile, again, as a consequence of Nick Dunning-- we couldn't do what we could do without Nick-- he indicates that you see the sand levels. Well, sand at Tikal is just not around. You've got to go at the nearest source, according to Nick who scouted out these things, is about 50 kilometers away.

[00:44:36.99] And once you get it to the foot of Tikal, you've got to go up another 50 meters. So it's not there easily. In fact, it's being brought in. And why it's there, we're assuming, maybe it's a bit of a stretch, it's there because they are filtering. And these are actually the smoking gun, the berms that water was filtered through at the ingress to these reservoirs has blown out with regularity. Because it did rain hard and replaced.

[00:45:05.73] Highly ritualized definition of water allocation. Pretty clear. This is a true bird's eye view, I guess a plan map, and the discolorations represent the districts that water was being moved off in the various areas from the summit. And the center here, this is that 62 hectare area. It's internally draining, and then the reservoirs at its margin is being opened up and allow it to move laterally and down slope.

[00:45:35.91] You'd basically use the water, potable presumably. And then as it moved through, it befouled and by the time it got down to these bajo margin tanks, in some cases, it would be a gray water, but you have a dry period for those four months or so at places like Tikal and elsewhere, you could get a third crop. It's gray water, but it's perfectly unusable. And by capturing it and then releasing it from that location into these bottles, that's what this discoloration is, you could plant again, and that would be very useful. Clever people. Clever people.

[00:46:13.89] This is a CELA 22, and Robert, you know a lot more about this than I do, but the argument has been that bloodletting, as you all are aware in the Maya area is a major force in their ideology and world view. Perhaps those beads according to the David Stuart, who I'm sure you have here in the past and an alumnus, may be water.

[00:46:42.52] And the reason I go there is my work in Bali where you have kings or certainly rich, old leaders that walk around water temples and basically our cultural extension officers this too. You have to be many hats to govern as we all know, and we hope there will be one woman that does that well in the future.

[00:47:09.88] This is some closing points to a degree. Tropical environments tend to be ones that have heavy precipitation, but, of course, are fragile and require dispersion. I mentioned that already. The biophysical pathways are very complicated and mobile. They rapidly move. It's a food webs, basically, and things change really quick.

[00:47:35.71] The jungle, if you will, the tropical rhythms are alive. They are heaving with organic breath, and that requires a certain kind of human constitution to deal with it. And you must be flexible. That's the clever nature of this marvelous group.

[00:47:55.04] Intensification. Social organic storage. Great problem as I mentioned at the outset, but we have these root crops. That's a possibility, likelihood. Recently there's been some work at a place called Ceren in Salvador, and they've got these great casts of manioc. It's there, and they're probably using it really a lot. I'll come back to Surin too in a moment, but you still have a problem.

[00:48:21.73] So calendars, which really translated into scheduling, if you look at it economically, may be more than just political or ideological. That's where we've gone for years. But perhaps there's something embedded that we're not seeing. It will be very difficult, and I'm the last person to tease this out, that is going on with regard to calendars. This has to do with timing, the movement of things, people, ideas, and scheduling them in an environment that needs flexibility. Predictable.

[00:48:53.14] And these kings and queens and their entourage may be involved in a complicated game of trade and movement too. If that's the case, you've got to move it on some thing. Roads. We're finding roads are much more widespread in the Mayan area than we thought. At Ceren, there is a marvelous sacbe It's about that thick. The only reason it's preserved is because of four meters of tephra that's buried it.

[00:49:19.63] Now, if that's the case, how many of these are we losing? Now, there's one enigmatic road. It runs about 100 kilometers, east to west, Yashu Ne to Coba. People just scratch their hands. 100 kilometers. That is an indication of the interest these folks had in moving stuff. And I think this and that produce a different kind of consumption practice, in coordination that may be embedded as we move through with future-- it's a hypothesis, but I think it's going to work.

[00:49:54.94] Labor was fundamental. No wheel. No beast of burden. No sail. No metal tools. How in the heck did they do this? They organized in a very skillful way their labor pool, and I could talk about that later.

[00:50:16.09] Closing. Promise. One thing, these are elements that I've looked at so far and the community element with water globally around waterholes is well known, ethnographically and historically. A community is defined by these places many times. So you go to West Africa, East Africa, great gossip occurs around the watering hole. You put in a standpipe somewhere and they may close it off because you can't talk to your neighbor.

[00:50:42.16] We're into being antiseptic, and that's it. No doubt about it. I means that people are dying because of waterborne disease. But to maintain social coordination, we have to think beyond that or in concert with that.

[00:51:00.22] The illness I want to mention in closing are that on the Earth right now, there are two things that are really going affect us by 2100, one is population density. Most recent estimations for population on this planet are four billion more people than 100 years. We're already at seven billion. Where do they go? They gravitated towards these nucleated centers, these great cities.

[00:51:26.87] The other part of this is that sea levels will rise, most recently argued it used to be about a meter by 2100, now estimates are close to two meters. Those are two significant variables that are converged in the next 100 years.

[00:51:43.96] Right now there are 23 megacities on the planet. That's something in order of a million or better people in a megacity, probably a lot bigger than that. 16 of them are coastlines. You just saw what happened with Matthew, and you've got Sandy and Katrina and the Philippines and Japan. It's a changing world.

[00:52:09.08] So how are we going to adjust to all this? Just a simple corrosion of excess salt water, never mind a storm surge. What's that going to do to our coastlines? What's it going to do to those cities? How are we going to redefine them? This is where archeology has a place at the table.

[00:52:24.73] We've got this dispersed adaptation that many semi-tropical parts of the world have demonstrated, and they get along really well. Maya 1500 years or better. Perhaps using that kind of modeling and the notion too that there are seven million cell phones out there. There are more cell phones in this world than are people right now.

[00:52:50.05] Think of that. Well, maybe you could turn that a quarter turn in the sense that more people can work at home. People can work in a rural area. And if you disperse your population, a-la our low-density, urban aggregates from the past, the Angkor, Maya, West Africa, Sri Lanka, these are all places where you have high civilization and they didn't live on the landscape in that manner, then what do you do?

[00:53:14.89] Well, maybe you lower the size of our urban hubs, have people work at home, but out in the hinder lands where the resources are, and we basically take those villages, give them a different kind of definition than they had in the past. It raises the level of community, and they can communicate.

[00:53:37.91] Now, how do you get goods back and forth? Light rail. New ways of catalyzing, moving goods differently. Archaeologists ought to be at the table when we start discussing this new world. Well, I'd better close. I'm talking too much. Thank you.