Sustainable Cities: Water, Trade, and the Human Population

As we work towards a sustainable landscape in our current world, cities around the world have shown variable amounts of sustainability. Examples in early Mesoamerica show similar limitations. The Olmec civilization based around agriculture in fertile soils deposited in floodplains and slash and burn agriculture. One of their cities, La Venta, was built on in island the drainage basin of a river with associated farming on nearby fertile fields (Renfrew and Bahn 1018). After about 1000 years of existence, La Venta declined, corresponding to a rise in Maya power and shifting river channels possibly affecting transportation (1022). Although the causes of the decline are not very well understood, it is possible that a decline in trading power led to an inability to trade for enough food to sustain the population of the island. At the same time as changing water availability, these socioeconomic relations could have significantly contributed to the decline.

Parts of Mayan civilization decline was likely also based around water scarcity. Mayas used intensive agricultural techniques including reservoir systems and agroforestry (Lentz et al.). The Maya city of Tikal was inhabited from 500BCE to 900AD (“Tikal National Park”). These farming techniques, along with some agricultural adaptations, allowed the city to survive a drought (Douglas et al.). However, at about 850 AD, the system began to fail (Douglas et al.). Reservoir systems were essential in watering crops, but also decreased the rechargeof springs. This created a system dependent almost entirely on rainwater for both agriculture and drinking water. Deforestation and forest thinning then caused a feedback loop lowering the amount of rain in the area. Combined with having a population near or exceeding the carrying capacity of the land, a drought became an issue too big to adapt to.

Map of reservoir system in Tikal

Left: A pyramid erected during the peak of Tikal
Right: The last artifact erected in Tikal in 869 AD, showing the deterioration of social functions in the city.

Previous cycles of collapse had seen the lands abandoned repopulated after the natural resources were replenished (Masson), however this was not the case in this instance. Maya culture continued in the north, shifting importance to maritime trade and alliance making in the Caribbean (Masson), but the south was mostly abandoned.

Both of these cities faced issues partially based on population size. In La Venta, the location of the city likely made it challenging to support a large population without external trade. In Tikal, the agriculture was more exploitative of the land, and while able to support people for a while, eventually led to climate change. In both areas, increasing population size led societies unable to adapt to changing environmental and socioeconomic factors.

Human populations are currently at an all-time high and are climbing. At the same time, we are rapidly diminishing standing reserves of many resources and there is relatively rapid climate change. All of these factors are leading to changing socioeconomic and political relationships between people, which could potentially lead to conflict. In the US, there is no one location where everything necessary to our way of life is produced, all foods, technologies, etc., and many of our current solutions closely match those used by these two cities. La Venta warns of the dangers of over-reliance on trade and external influence, and the possible consequences of being unable to produce enough of a product within one’s own people. Tikal emphasizes that our nation cannot become stagnant. Even though one solution may have worked in the past, a novel approach may be needed for us to continue in the future.

Sources:

Douglas, P. M., M. Pagani, M. A. Cantuo, M. Brenner, D. A. Hodell, T. I. Eglinton, and J. H. Curtis. “Drought, agricultural adaptation , and sociopolitical collapse in the Maya Lowlands.” Proceedings of the National Academy of Sciences of the Unites States of America, vol. 112, no. 18, 5 May, 2015, pp. 5607-5612., doi:10.1073/pnas.1419133112

Lentz, D. L., N. Dunning, V. L. Scarbourough, K.S. Magee, K. M. Thompson, K.Weaver, C. Carr, R. E. Terry, G. Islebe, K. B. Tankersley, L. G. Sierra, J. G. Jones, P. Buttles, F. Valdez, and C. E. Ramos. “Forests, fields, and the edge of sustainability at the ancient Maya city of Tikal.” Proceedings of the National Academy of Sciences of the Unites States of America, vol. 111, no. 52, 30 Dec. 2014, pp. 18513-18518., doi:10.1073/pnas.1408631111.

Masson, M. A. “Maya Collapse Cycles.” Proceedings of the National Academy of Sciences of the Unites States of America, vol. 109, no. 45, 6 Nov. 2012, pp. 18237–18238., doi:10.1073/pnas.1213638109.

Renfrew, Colin, and Paul G. Bahn. The Cambridge World Prehistory. Vol. 2, Cambridge University Press, 2014.

“Tikal National Park.” UNESCO World Heritage Centre, United Nations, whc.unesco.org/en/list/64.

Photo sources:

b3_010_011. 18 Oct. 2006, mayaruins.com/tikal/b3_010_011.jpg. 

Kollecting-Koordinates-Tikal-6. 19 Feb. 2017, www.kollectingkoordinates.com/wp-content/uploads/2017/02/Kollecting-Koordinates-Tikal-6.jpg.

urn:cambridge.org:id:binary:2659:20160526051323287-0663:02793fig2_1. 16 May, 2016, https://static.cambridge.org/resource/id/urn:cambridge.org:id:binary:2659:20160526051323287-0663:02793fig2_1.png?pub-status=live

For future reading:

Scarborough, Vernon L, et al. “Water and Sustainable Land Use at the Ancient Tropical City of Tikal, Guatemala.” Proceedings of the National Academy of Sciences of the United States of America, vol. 109, ser. 31, 31 July 2012, pp. 12408–12413. 31, doi:10.1073/pnas.120881109.http://www.pnas.org/content/109/31/12408.full?sid=d3df8792-8d88-4136-be4a-d4660368c11b

Salazar, Cristian. “How New York City Gets Its Water: From Resevoir to Tap.” Am New York, News Day, 22 Mar. 2017, www.amny.com/lifestyle/how-nyc-gets-its-water-1.9205765.

Leave a Reply