1.0 Introduction
In the ancient world, many civilizations thrived for hundreds of years and had cities with large populations (Smith, 2007). These cities existed before the development of contemporary formal urban planning practices (which started around the industrial era, when they emerged for the betterment of urban cities by improving the quality of life of the working class) (Filion et al., 2015).
However, many ancient cities around the world showed non-geometric planning and degrees of coordination to the layout of their structures well before the industrial revolution (Smith, 2007). These ancient cities flourished for hundreds of years (Smith, 2007).
One reason that large populations would establish in an urban settlement is that there was a surplus amount of resources to support the continuing growth in population due to agricultural development and animal husbandry (Diamond, 1999). These large settlements often developed from smaller, agricultural settlements that were able to support an increased population, like the city of Tikal (in modern day Guatemala) during the Mayan civilization and Chaco Canyon (in modern day New Mexico, USA) during the Anasazi civilization.
However, the absence of ecological resiliency in their planning had also contributed to the downfall of these cities belonging to these great ancient civilizations (Diamond, 2005). In this context, resiliency refers to the ability of the urban systems to be ecologically adaptive and sustainable so they are able to maintain or return to their desired state following a disturbance or chronic stress that ensues from resource usage in the environment, or a natural disaster (Pickett et al., 2013),
There are essential properties of ancient urban areas that can be used to understand and classify them (Filion et al., 2015). One of them is production, as settlements with large populations have a large surplus in food from resources like agriculture and animal husbandry (Filion et al., 2015; Diamond, 1999).
The production of food allowed for human reproduction, as children would be able to survive to older ages and be able to help support the city’s labour (Filion et al., 2015). Because of the surplus of food in ancient cities, citizens did not have to be limited to farming and instead could be involved and specialized in other forms of production and income generation, such as ceramic, stonemasonry, or carpentry (Filion et al., 2015). Trade routes also helped in the flouring of larger populations in urban centres as goods were imported and exported with other settlements (Filion et al., 2015).
Once the populations became large enough, the need for some form of governance emerged in order to manage (and control) the masses, including their spatial distribution (such as, through planning for and constructing plazas, towering monuments, and broader streets that display power, whether military, political, or religious) (Filion et al., 2015).
The act of building these significant monuments served to display the wealth from the agricultural surplus and give citizens a sense of place (Smith, 2007; Filion et al., 2015). In a sense, these are common factors between ancient cities and contemporary ones (Lynch, 1981).
2.0 Tikal
Tikal is an example of a prosperous ancient city (Smith, 2007). Part of the Mayan civilization from approximately 2000 BC to 900 AD, Tikal was able to grow because the communities could feed, house, and protect a large number of citizens, which in turn could work and fight for their community (Haviland, 1970; Smith, 2007; Lentz et al., 2014; Diamond, 2015).
Tikal was one of the largest cities in the Americas with massive palaces, pyramids, and many residences for its large population (Haviland, 1970). Food was readily available through crops such as the traditional squash, corn, and beans in the lowlands, as well as breadnut trees found on citizen properties near the centre (Haviland, 1970).
Due to the availability of food production, and by consequence trade of luxury goods, salt, and cacao (Lentz et al., 2014)., evidence of Tikal’s wealth is displayed in many luxury archeological artifacts from daily life, including necklaces made of jade and shell ornaments (Haviland, 1970).
Furthermore, the prosperity in agriculture allowed for a complex religion and political structure, which symbolized higher meaning in the built urban form (Haviland, 1970; Smith, 2007). Although there are no records of how Tikal was developed and planned, evidence on its formal planning exist through the thoughtful coordination of buildings and spaces in its urban core (Smith, 2007).
In Tikal, there was an epicentre, which had monumental architecture, a grand plaza, and elaborate ceremonial structures (Haviland, 1970). The urban core was the administrative and power centre of the city, indicating where elites, like rulers and priests, would reside (Haviland, 1970; Smith, 2007). As the city become more powerful, it had more control over the growing population due to increases in resources and complex higher form structures, which led to the city growing outward from the centre (Haviland, 1970).
As the distance from the centre and its public architecture increased, however, the areas of residential housing for the ordinary working-class citizens began to take the form of unplanned growth (Haviland, 1970; Smith, 2007). Indeed, there seems to have been little planning or coordination in these outer residential areas, in contrast to the monumental and coordinated epicentre (Smith, 2007).
2.1 Lack of Environmental Sustainability
The ancient civilizations, which were once immensely prosperous and populated, eventually collapsed (Diamond, 2005). From the disintegration of Tikal, it is possible to learn applicable lessons for modern-day cities that might enable them to withstand contemporary environmental challenges like climate change (Diamond, 2005).
Regardless of their innovations, resources, population, and wealth, ancient civilizations still collapsed because of poor environmental sustainability in their cities (Abrams & Rue, 1988; Diamond, 2005). Natural disasters, such as drought, exacerbated by poor environmental planning and the overexploitation of resources, resulted in the collapse of ancient cities and societies (Diamond, 2005; Douglas et al., 2016). The lack of resiliency in planning Tikal led to exceeding the carrying capacity of the surrounding land (Abrams & Rue, 1988; Diamond, 2005).
Specifically, deforestation ensued in Tikal as a result of cutting trees to build houses and monuments, clear land for farmland, and for fuel and was one of an array of other reasons that led to the environmental degradation of land (Abrams & Rue, 1988). According to Lentz et al., 2014, deforestation for fuel (for firewood, ceramics production, and lime manufacturing for plaster to build more housing) were among the root causes for overexploitation of forests as natural resources.
Such deforestation caused an extreme nutrient loss in the soil through erosion, and in turn, resulted in negatively impacting agriculture by yielding far less produce (Abrams & Rue, 1988). Moreover, during heavy rainstorms, the soil, which was weakened by deforestation, easily eroded, thus further ruining harvests and crops (Abrams & Rue, 1988).
There is strong archaeological evidence that these conditions were exacerbated by intense drought that eventually caused societal collapse, indicating that this city was not able to withstand shifts in the climate (Diamond, 2005; Douglas et al., 2016). Tikal’s physical layout (i.e., urban form) was not designed with drought in mind (e.g., no water harvesting to prepare for multiple periods of drought), and because of the deforestation combined with the increased population numbers, it was unable to provide, let alone conserve the necessary resources to recover or be resilient (Diamond, 2005).
Indeed, the ratio of land per capita combined with the ratio of planting per fallow years were insufficient to sustain Tikal’s population (Lentz et al., 2014) rendering this population either at the risk of starvation or with the option of leaving Tikal (Abrams & Rue, 1988; Diamond, 2005). Because Tikal was not a sustainable city (due to the lack of environmental foresight that balances resource consumption vis-à-vis the growing population), it eventually collapsed (Diamond, 2005).
2.2 Warfare
Warfare also contributed to societal disintegration in Tikal (Diamond, 2005). Due to the uncontrolled consumption of resources by the growing population, land became scarce and viable agricultural land eroded with continuing deforestation (Abrams & Rue, 1988; Diamond, 2005).
Infights broke out among the excessively large number of Tikal’s inhabitants due to competition over land and resources – archaeological evidence points to murders committed over food during droughts (Diamond, 2005). Because the land was not planned out in zones designated for specific uses, the residents would compete to utilize any land outside the epicentre for their needs (whether for residential or productive uses), thus resulting in cramped, unhealthy living conditions once the populations became too large (Diamond, 2005; Smith, 2007).
Warfare among the various cities in the Mayan civilization was also frequent (Diamond, 2005), hence leading to the re-allocation of resources away from the citizens towards the armies (Diamond, 2005). Furthermore, during periods of drought, society blamed the king for failing to protect the harvests and therefore, he would be brutally sacrificed (Diamond, 2005).
This lack of long-term sustainability planning for the increasing population and subsequent exploitation of the resources, combined with political upheavals caused the collapse of many great cities during the Mayan civilization, included Tikal (Diamond, 2005).
3.0 Chaco Canyon
The Anasazi civilization existed in the Southwestern United States around 900 to 1350 AD, where they lived in Chaco Canyon, which consisted of an extensive array of stone buildings (Lekson et al., 1988; Diamond, 1994). The community is built of several hundred stone houses, with nine great houses that served as the centre of Chaco Canyon (Lekson et al., 1988).
Before the advent of contemporary formal planning as it is known in the Western world today, the Anasazi civilization had elaborately designed homes, agricultural irrigation, roads, enough food for a growing population, and a form of governance under the rule of the elites who lived in the great houses (Lekson et al., 1988). As a result, the population of the Anasazi grew outstandingly in numbers and became one of the greatest civilizations in North America.
The wealth of resources in their homeland enabled the Anasazi to support their large population and create such complex structures (Diamond, 1994). The land where the Anasazi built the Chaco Canyon was once productive forestland that provided timber and fuel for their needs (Diamond, 1994).
The coordination of their stone buildings and agricultural irrigation systems is an acknowledgement of their reputation (Lekson et al., 1988). Control over their resources allowed the Anasazi to utilize them in ways to promote the production of goods and structures for their growing number of citizens (Lekson et al., 1988).
3.1 Lack of Environmental Sustainability
The lack of environmental sustainability, similar to Tikal, also resulted in the collapse of the Anasazi civilization because of land deforestation (Diamond, 1994). The lack of strategies to manage forests in Chaco Canyon decreased its resiliency due to the soil erosion and lack of regrowth of the cleared vegetated areas, which resulted in serious damage to the agricultural lands (Diamond, 1994).
Such environmental degradation that negatively impacted Chaco Canyon’s arable land caused a collapse in its local food supply which, combined with a loss of drinking water, resulted in the community’s loss of resilience (Wills et al., 2014) and eventually led to societal collapse (Haas & Creamer, 1993).
Because the rainfall in the Southwestern United States is highly variable, the Anasazi depended on irrigation for agriculture (Lekson et al., 1988; Diamond, 2005). Chaco Canyon’s planning included storage for surplus food because, originally, their agricultural production was the reason for the substantial increase in population and development of a complex society (Lekson et al., 1988).
However, what planning lacked in Chaco Canyon was long-term water management strategies. Irrigation channels cut deep arroyos that eventually lay below the water table (Diamond, 2005), hence, without groundwater table at field levels, the eventual periods of intense drought resulted in mass starvation and, consequently, the breakdown of their city (Diamond, 2005).
3.2 Warfare
The environmental conditions began to disintegrate, and because of the continued depletion of resources due to poor sustainability planning and increased population numbers, the Anasazi engaged in infights and external warfare to compensate for their lost natural and agricultural resources, including arable land and water (Diamond, 2005, Haas & Creamer, 1993).
There is even evidence of cannibalism at Chaco Canyon in the periods after the drought (Diamond, 2005). Consequently, the lack of resilience that led to starvation and fighting, prompted the citizens of Chaco Canyon to migrate elsewhere, hence, abandoning their once-prosperous city (Diamond, 2005).
4.0 Contemporary Society
In 2018, the human population of the planet had exceeded 7.6 billion, with the highest rising populations occurring in Asia, Africa, and South America (Roser et al., 2019). Concurrently, urbanized areas are increasing in concentration and becoming home to a greater proportion of the world’s growing population (Pickett et al., 2013).
Although the ecological footprints of cities vary, cities generally speaking cover less than 3% of the world’s surface yet consume large quantities of resources and emit approximately three-quarters of the earth’s carbon emissions (Meerow et al., 2016). The increasing urbanization, deforestation, and resource consumption are some of the reasons for the decrease in natural ecosystems and species diversity, which results in instability in the natural equilibrium and the loss of essential services for human well-being (Alberti & Marzluff, 2004; Andersson, 2006).
Socio-ecological systems in urban areas are under the imminent threat of the loss of natural systems and the climate crisis, making urban climate resiliency an essential factor in contemporary city-building (Meerow et al., 2016) and not differently from how it was in ancient cities like Tikal and Chaco Canyon. Similar to these historic cities, contemporary societies are facing an overpopulation crisis as well as extensive resource exploitation.
Contemporary society is also witnessing natural disasters unfold and equilibriums of natural systems changing (IPCC, 2018). Similar climatic stresses are currently affecting millions around the world by altering food security and agriculture because of the varied weather patterns, changes in the growing season, and global temperatures, which result from the increase in carbon emission (USGCRP, 2018).
The increase in carbon emissions from human activities and resource extraction traps heat in the atmosphere and causes a warming effect that is melting the glaciers and ice caps, acidifying the oceans, and consequently destroying marine ecosystems, such as the coral reefs (USGCRP, 2018). The destruction of natural ecosystems damages the climate resiliency of our planet, and especially degrades the services that such ecosystems provide in support of the planet’s human population (USGCRP, 2018).
As the quantity and quality of ecosystems degrade, their equilibrium shifts and many ecosystems cannot withstand such chronic stresses and as such, the system collapses by surpassing a threshold (Alberti & Marzluff, 2004; Picket et al., 2013). This leads to a loss of significant “services” that these ecosystems provide, from the regulation of gas, climate, and disturbances, to the provision of resources like water, nutrients, and food, to the cultural and recreational among others (Bolund & Hunhammar 1999; Costanza et al., 1997).
Without substantial and sustained reductions disturbances and the reduction of carbon emissions, negative transformative influences will occur on our ecological systems, including, among others, the coral reef and sea ice ecosystems (USGCRP, 2018). As a result, the current functions of these ecosystems, such as air and water purification, protection from coastal flooding, crop pollination, and providing materials for development, will be significantly disrupted and/or cease to exist altogether, and the consequences, which will be cumulative due to the interconnections among these ecosystems, will thereby be enormous (USGCRP, 2018).
Current cities, which are currently facing the degradation of their ecosystems, must draw valuable lessons from ancient cities that underwent collapse due to analogous reasons. The Intergovernmental Panel on Climate Change has prepared numerous reports on climate change. It has assessed the anthropogenic climate crisis as one of the greatest threats to human civilization (IPCC, 2018).
With high confidence, a 1.5ᵒC increase in global temperature will cause increased drought in the Mediterranean region, extreme heatwaves across Central and Eastern North America and Europe, as well as the Mediterranean, Southern Africa, and Western and Central Asia (IPCC, 2018). It is imperative to underscore that current empirical studies have proved, beyond doubt, that these trends are already happening, hence, the change in language from “climate change” to the “climate crisis” and “climate breakdown” (Monbiot, 2017; Carrington, 2019).
For example, the loss of several ecosystems, combined with heavy precipitation events in high-latitude regions, and an increase in the intensity of tropical cyclones and Atlantic hurricanes are also expected to occur with high confidence (IPCC, 2018). Cities, in particular, are anticipated to have life-threatening heatwaves due to the urban heat island effect, an increase in vector-borne diseases, food and water security, and an increase in poverty and inequality (Picket et al., 2013; IPCC, 2018).
These are significant threats to cities across the globe (Pickett et al., 2013). As such, it is critical to understand how modern cities can mitigate these disturbances through climate resiliency planning to avoid becoming a victim of the collapse of civilization.
Striving to build resilient urban systems is essential for the well-being of the population, economy, and environment (Schewenius et al., 2014). Climate resilience planning needs to be analyzed to understand better how it can enrich cities and also determine whether contemporary strategies, such as municipal natural asset inventory management, are beneficial or maladaptive (MNAI, 2017).
In an increasingly globalized world, ramifications for environmentally unjust planning will have global consequences. In contrast, successful environmental planning can be a foundation for other cities and countries to build upon to create a more sustainable world (Schewenius et al., 2014).
5.0 Conclusion
Large cities belonging to ancient civilizations developed and flourished for hundreds of years before the creation of Eurocentric formal urban planning that occurred after the industrial revolution (Smith, 2007). These cities had high coordination in the epicentre to demonstrate the ruler’s power and control and consisted of vast residential areas surrounding the urban centres (Smith, 2007).
Tikal and Chaco Canyon are two cities that had prosperous communities and complex societies for hundreds of years due to wealth in resources and fruitful agricultural production that resulted in production, governance, capitalization, trade routes, and reproduction (Diamond, 2005; Filion et al., 2015). A lack of climate resiliency planning in these cities eventually resulted in uncontrolled growth and overpopulation that resulted in environmental degradation (Diamond, 2005).
The environmental degradation resulted in the loss of their agricultural production and dramatically reduced the living conditions in their city, causing violence among citizens that disintegrated their cities (Diamond, 2005).
Despite the shortcomings of these ancient civilizations, they thrived for hundreds of years. Their cities survived for much longer than the current timeframe of the capitalistic North American society. These cities did not plan for future shifts in climate and did not plan to make their cities climate-resilient (Diamond, 2005).
By destroying the natural environments for short-term gain, these ancient cities were ruined and thus abandoned (Diamond, 2005). However, modern societies can learn from these mistakes and plan for environmentally sustainable communities by ensuring that ecosystem functions are not degraded and that environmentally sensitive lands are protected (Diamond, 2005).
Modern-day cities will need to create long-term climate action policy plans and have initiatives to promote sustainability to protect the well-being of cities and citizens; and to ensure carrying capacity for local ecosystems is not exceeded in order to not fall victim to environmental and societal collapse (Diamond, 2005; IPCC, 2018).
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